Yodl 4.03.03

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# Chapter 4: Macros and Document types

The macro package distributed with `Yodl` is described in this chapter. The macro package consists of a number of definition files, which convert a Yodl document that follows a certain syntax to an output format. The main output formats, currently supported, are:

- HTML;
- LaTeX (plain LaTeX, no `latex2e`);
- The `groff` `man' format which is used for man pages;
- The `groff` `ms' format which is more expressive;
- Basic, plain text

The following conversion format is in an experimental stage:

- XML, as used by the University of Groningen's so-called `webplatform'.

Currently discontinued conversion formats are:

- SGML, although the basic macros are available. SGML can probably be reactivated fairly quickly. Contact the maintainer if support for SGML should be reinstated
- texinfo, mainly due to the fact that the current maintainer doesn't know what the required post-processing actions are.
- tely, since this conversion format is unknown to the current maintainer.

Other formats may be available, but maybe in an unstable state. Contact the the maintainer if you have a new format to add, or want to reanimate formats that were previously available.

## 4.1: General structure of a Yodl document

This section describes the general format of a Yodl document.

First of all, a Yodl document needs a preamble. This part of the document must be at the top, and must define the modifiers and the document type. Modifiers, when present, must appear first.

Modifiers are often specific for a particular target document type (e.g., `latexoptions` or `mailto`), but may also have a general nature (e.g., `affiliation` or `abstract`). All modifiers are used to modify parameters of document types. Therefore, they must be specified before the document type is defined.

All modifiers are listed in section 4.3.7. In general, you should use as many modifiers as appropriate. E.g., you should define a `mailto` even when you're not planning to convert your document to HTML. The reason is twofold: first, you might later decide that a HTML version isn't a bad idea after all. Second, later versions of the converters might use `mailto` even for non-HTML output formats.

Following the modifiers, the document type is defined. The document type is either `article`, `report`, `book`, `plainhtml` or `manpage`. Except for the `manpage` document type, which is a highly specialized document type, described in section 4.1.2, the following rules apply:

A decision about the document type to use should be based on its complexity. If the document's organization becomes too complex, it is probably a good idea to use a document type supporting a more complex organization. E.g., a complex article might be written as an accessible report, combining related sections into chapters. Similarly, the structure of a report having 30 chapters might improve when it's re-organized as a book having parts. To offer a rule of thumb: a document should have no more than approximately ten top-level sections, and each top-level sectioning should have no more than approximately ten subsections, etc..

The document type influences the way Yodl formats the output. An `article` (or `plainhtml`) results in one output file. E.g., one final document when converting to HTML. If your article is way too long, then the loading of the HTML document also requires much time. When converting to HTML, Yodl splits `report`s and `books` into files each holding a chapter. These can be accessed through the table of contents. So, the document length can also be relevant when you contemplate switching to a `report` or `book`.

Documents using special macros, must have defined these macros before they are used. An appropriate location for these macros is immediately beyond the preamble. E.g., see the file `Documentation/manual/manual.yo` distributed with the Yodl package. This is the main file of this manual, showing the preferred organization of Yodl files.

To answer yes-but-what-if oriented minds, here are two results of the wrong order of text, preamble and modifiers:

- If you put text before the preamble, i.e., before stating the document type, chances are that Yodl happily translates the file, but subsequent states probably fail. E.g., the `<html>` tag would come too late in a HTML conversion, causing the HTML browser to become confused. Or, the `\documentstyle` definition would be seen too late by the LaTeX typesetter.
- If you put modifiers, such as `latexoptions`, beyond the document type, then these modifiers have no effect; though Yodl won't complain either. The reason for this being that the definitions of such modifiers are encountered only after the stage where they were needed....

### 4.1.1: Document types

As distributed, Yodl supports four document types: article, report, book and the manual page. Note that document types are essentially unrelated to output formats; a book can be converted to each of the output formats, and a manual page can be converted to a `.html` file. Nevertheless, some formats are particularly useful for some document types. A book converted to the `man` output format to be processed later with `groff` won't look too good. Its looks would greatly improve when the document would be converted to ASCII using the `ms` output format.

Following the preamble and the definition of specialized macros symbols and counters, documents start by specifying the document type. The available macros are:

- `article(title)(author)(date)`: The `article` document type should be used for short documents. Its arguments specify the document's title, author and date.

  In articles, the title page is numbered and the table of contents is on the title page. The sectioning commands `sect`, `subsect` etc. are available.

- `report(title)(author)(date)`: The `report` document type differs from an `article` in that it has a separate unnumbered title page, a table of contents on a page of its own, and it supports the sectioning command `chapter` in addition to the ones supported by `article`s. A `report` should be used fir larger documents.
- `book(title)(author)(date)`: The `book` type is for even larger documents. In addition to the sectioning commands supported by `report` it supports the sectioning command `part`.
- `plainhtml(title)`: This document type is typically used in HTML output. It's implemented for situations where you only need to create a HTML file, but want to use Yodl to help you by providing useful macros. This document type is similar to `article`, but does not require you to specify `author` and `date` arguments (In fact, you can emulate `plainhtml` by using an `article`, using empty author and date arguments).
- `manpage(title)(section)(date)(source)(manual)`: The `manpage` document type should only be used to write Unix-style manual pages. It uses its own sectioning commands to reflect the necessary sections in a manual page. This document format is described separately in 4.1.2.

These macros provide, globally, three functions: First, the macros generate any commands that need to appear before `real' text is sent to the output file. E.g., the LaTeX output needs a `\documentstyle` preamble, HTML output needs `<html>` and `<body>` tags.

Second, the macros define appropriate document-dependent settings. E.g., the LaTeX converter defines the title, author and date using `\title` etc..

Third, the actual document is started. E.g., for LaTeX this means a `\begin{`type`}`, followed by the appropriate commands to generate a the document title and the table of contents. The `title` setting in the above macros defines the document title which always appears on the front page of the document. For HTML output, this is also the title of the HTML file (or files), as appearing in the HTML `<title>` tag.

The fact that the macros defining the document type perform many functions means that once the macro is started, nothing `extra' can be inserted between, e.g., the generated title and the table of contents. Sometimes this is not what you'd like; as is the case with an abstract. Yodl therefore uses modifiers, appearing before the document type macros, to insert information between the various elements of a document definition.

### 4.1.2: The manpage document type

The manpage document type was implemented to simplify the construction of Unix-style manual pages. `Yodl` mapage documents can be converted to `groff` documents (using `yodl2man`), to `html` documents (using `yodl2html`), or to plain ascii text documents (using `yodl2txt`).

A manpage document must be organized as follows:

1. The manual page itself is defined, using the macro

       manpage(short title)
                   (section)
                   (date)
                   (source)
                   (manual)

   Its arguments are:
   Short title:
   This should be the program name or something similar; i.e., whatever the manpage is describing.
   Section:
   A number, stating the manpage section. The Linux man (7) page recognizes the following manpage sections:
   - Section 1 is for commands, like `ls`;
   - Section 2 is for system calls, like `fork()`;
   - Section 3 is for library calls, like `strdup()`;
   - Section 4 is for special files (like devices);
   - Section 5 is for file formats, (like `syslog.conf`);
   - Section 6 is for games;
   - Section 7 is for macro packages and conventions;
   - Section 8 is for system management commands;
   - Section 9 is for other types of manpages, such as kernel commands.
   Date:
   The date of release.
   Source:
   The package where the manpage belongs to.
   Manual:
   The manual to which the package belongs.
   The arguments of the manpage macro define, e.g., the headers and footers of the manual page. The `date`, `source` and `manual` arguments can be empty.
2. The subject of the manpage is defined using

           manpagename(name)(short description)

   The `name` argument should be a short name (e.g., the program name), and the `short description` should state the function. The descriptive argument is used by, e.g., the `whatis` database.
3. The synopsis starts after:

           manpagesynopsis()

   Following this, an abbreviated usage information is presented. This information should show, e.g., the possible program flags and required arguments; but no more.
4. The description is given after:

           manpagedescription()

   This is followed by some descriptive text. The descriptive text can e.g. show what the program (function, file, game, etc.) is supposed to do.
5. Options are expected after:

           manpageoptions()

   The options are typically a descriptive list of possible flags and their meaning. This section lists the information of the synopsis, but also gives an in-depth description. The `manpageoptions()` section is optional.
6. Necessary files are listed after:

           manpagefiles()

7. The `see also' entry is defined by:

           manpageseealso()

   This is then followed by a list of related manual pages. Here, use the format `bf(topic)(sectionnr)`, e.g., `Yodl`(1).
8. Diagnostics are described after:

           manpagediagnostics()

   Diagnostics can state, e.g., what error messages are produced by the program and what the cure is.
9. Known bugs should be mentioned after:

           manpagebugs()

   This section is optional.
10. Finally, the author is stated after:

            manpageauthor()

The `manpage` document type requires you to follow the above order of commands strictly and to state all the necessary sections (and optionally, to state the not required sections but in their proper sequence). Furthermore, sectioning commands that are available in other document types (`sect`, `subsect` etc.) are not allowed in a `manpage`. You can however insert other sections in the manual page with the macro `manpagesection`. This macro takes one argument: the title of the extra section. It is suggested that you type the section name in upper case, to conform to the standard.

As an example, the manual page for the `yodl` program follows (the actual manual page may differ):

        manpage(yodl)
               (1)
               (1996)
               (The Yodl Package)
               (Yet oneOther Document Language)

        manpagename(yodl)(main Yodl converter)

        manpagesynopsis()
        YODL [-DNAME] [-IDIR] [-oFILE] [-PCMD] [-pPASS] [-t] [-v] [-w] [-h]
        [-?]  inputfile [inputfile...]

        manpagedescription()
        This manual page describes the YODL program, the main converter of the
        Yodl package. This program is used by the bf(yodl2....) shell scripts,
        e.g., bf(yodl2tex) or bf(yodl2html).

        manpageoptions()
        description(
        dit(-DNAME) Defines symbol em(NAME).
        dit(-IDIR) Overrules the standard include directory (default
    em(/usr/local/lib/yodl)) with em(DIR).
        dit(-oFILE) Specifies em(FILE) as the output file (default is stdout).
        dit(-PCMD) `Preloads' command em(CMD), as if em(CMD) was the first line
    of the input.
        dit(-pPASS) Defines em(PASS) as the maximum number of `passes'; when this
    number is exceeded, YODL aborts.
        dit(-t) Enables tracing mode. Useful for debugging.
        dit(-v) Raises the verbosity mode. Useful for debugging.
        dit(-w) Enables warning. When enabled, YODL warns when it encounters
    inconsistencies.
        dit(-h, -?) Shows usage information.
        dit(inputfile) File to process, use em(-) to instruct YODL to read
    from stdin.
        )

        manpagefiles()
        The YODL program requires no files, but `normal' usage of the Yodl package
    requires macro files installed (usually in bf(/usr/local/share/yodl)). The
    files in this directory are included by the converters bf(yodl2txt) etc..

        manpageseealso()
        bf(yodl2tex), bf(yodl2html), bf(yodl2man), etc..

        manpagediagnostics()
        Warnings and errors of YODL are too many to enumerate, but all errors
    are printed to em(stderr) after which YODL exits with a non-zero
    status.

        manpagebugs()
        There may be bugs in the YODL program, but that's not very likely.
    More likely you'll encounter bugs or omissions in the macro package
    itself.

        manpageauthor()
        Karel Kubat

## 4.2: Predefined macros

This section describes all macros defined by default. Altering or removing these macros may produce unexpected results when converting `Yodl` documents to other formats. Furthermore, these macros often depend on macros or other symbols defined for internal use.

Many predefined macros depend on symbols start with `XX`. Therefore, it is strongly advised not to start any locally defined symbol with `XX` as doing so, or undefining existing symbols starting with `XX`, may also produce unexpected results.

Here are the default macros, alphabetically ordered:

### 4.2.1: abstract(text)

Defines an abstract for an article or report type of document. Abstracts are not implemented for books or manpages. Must appear before starting the document using the `article` or `report` macro.

### 4.2.2: addntosymbol(symbol)(n)(text)

Adds `text` `n` times to `symbol`. The value `n` may also be the name of a defined counter (which is not modified).

### 4.2.3: affiliation(site)

Defines an affiliation, to appear in the document titlepage below the author field. Must appear before starting the document with `article`, `report` or `book`. The affiliation is only printed when the author field is not empty. When converting to html the way the affiliation is displayed can be tuned using CSS id selector specifications. The affiliation has `id="affiliation"`.

### 4.2.4: AfourEnlarged()

Enlarges the usable height of A4 paper by 2 cm.: the top margin is reduced by 2 cm. This macro should be called in the preamble. The macro is available only for LaTeX conversions.

### 4.2.5: appendix()

Starts appendices

### 4.2.6: article(title)(author)(date)

Starts an article. The top-level sectioning command is `(n)sect`. In HTML conversions only one output file is written, while the way the headings are displayed can be tuned using CSS id selector specifications: the title has `id="title"`, the author `id="author"`, and the date `id="date"`. )

### 4.2.7: attrib(text)

In html, pushes `text` as an attribute for the next html tag supporting `attrib`. E.g, to set a blue color and 30 pixel left-hand side margin for a section use

        attrib(style="color:blue;margin-left:30px;")\
        sect(Section name)

This results in the html markup

        <h1 style="color:blue;margin-left:30px;">Section name</h1>

This macro is only effective with html conversions. It is applied in a stack-wise fashion: when multiple `attrib` calls are used, then the topmost attrib-string is added to the first macro calling the `attribinsert` macro, with subsequent macros using subsequent elements on the attrib-stack.

Commonly used attributes are `id="idname"`, expecting a `#idname` CSS label in either internal or external CSS specifications, or `style="spec"` (as shown in the example).

Example: when using

        attrib(width = "100" height = "100")
        attrib(id = "#fig")
        figure(imgfile)(Caption)(IMG)

then the `#id` attribute is applied to `<figure>`, and the `width` and `height` attributes are applied to `<img>`, which html markup is inserted by the `figure` macro.

The `attrib` macro is supported by the following predefined macros (between parentheses the number of attribute strings that are inserted by these macros; if only 1 attribute string is inserted no number is shown):

`bf cell cells center chapter code dashes dit em figure(3) file htmltag itdesc lchapter link lref lsect lsubsect lsubsubsect nchapter npart nsect nsubsect nsubsubsect paragraph part quote row sc sect strong subs subsect subsubsect subsubsubsect sups tableatt tbl tac tc tnac tnc tr tt ttbegin url verb verborg verbinclude`.

### 4.2.8: attribclear()

Removes any existing contents from the attrib-stack. This macro is only active when converting to html

### 4.2.9: attribinsert()

In html, if the attrib-stack is not empty, inserts the value on top of the attrib-stack and then pops the topmost value. If the attrib-stack is empty, nothing happens.

### 4.2.10: bf(text)

Sets `text` in boldface.

### 4.2.11: bind(text)

Generate a binding character (non-breaking space) after text.

### 4.2.12: book(title)(author)(date)

Starts a book document. The top-level sectioning command is `(n)chapter`, `(n)part` being optional. In HTML output files are created for each chapter, while the way the headings are displayed can be tuned using CSS id selector specifications: the title has `id="title"`, the author `id="author"`, and the date `id="date"`. )

### 4.2.13: cell(contents)

Sets a table cell, i.e., one element in a row. With the man/ms converters multiple blanks between `cell()` macro calls are merged into a single blank character.

Instead of using `cell` in `table`, consider using `tc` in `tbl`.

### 4.2.14: cells(nColumns)(contents)

Set a table cell over `nColumns` columns. With LaTeX and xml the information in the combined cells is centered.

With man/ms conversions the `cells()` macro simply calls the `cell()` macro, but here the `setmanalign()` macro can be used to determine the alignment of multiple cells.

With html the macro `attrib` can be used, but when it contains a `style` specification the macro's default `style="text-align: center"` is ignored (but it can optionally be specified using the `attrib` macro).

Instead of using `cells` in `table`, consider using `tnc` in `tbl`.

### 4.2.15: cellsline(from)(count)

Sets a horizontal line starting at column number `from` over `count` columns in a row. If `from` is less then the number of columns already added to a row then it is ignored. This macro must be embedded in a `row` macro defining a table row. To put a line across the table's full width use `rowline`. To set horizontal lines across columns 1 until 2 and columns 4 until 5 table of a table use:

        row(cellsline(1)(2)cellsline(4)(2))

Combining `cellsline` and `cell` or `cells` calls in one row produces undefined results.

Instead of using `cellsline` in `table`, consider using `tline` in `tbl`.

### 4.2.16: center(text)

Centers `text`. Use `nl()` in the text to break lines. In html the `attrib` macro is not supported, but a division (`div`) with style definition `text-align: center` is used. To center a table in html use the `tableatt` macro. If a `table` or `tableatt` macro is used inside a `center` macro then the contents of columns are column-wise centered.

Inside a `center(...)` context the counter `XXcenter` is unequal 0.

### 4.2.17: chapter(title)

Starts a new chapter in books or reports.

### 4.2.18: cindex()

Generate an index entry for LaTex() or texinfo c-indices. Its argument is the index entry. See also the `[fptv]index` macro.

### 4.2.19: cite(text)

Sets `text` as a citation or quotation

### 4.2.20: clearpage()

Starts a new page, when the output format permits. Under HTML a horizontal line is drawn.

### 4.2.21: code(text)

Sets `text` in code font, and prevents it from being expanded. For unbalanced parameter lists, use `CHAR(40)` to get `(` and `CHAR(41)` to get `)`.

### 4.2.22: columnline(from)(through)

Sets a horizontal line over some columns in a row. Note that `columnline` defines a row by itself, consisting of just a horizontal line spanning some of its columns, rather than the table's full width, like `rowline`. The two arguments represent column numbers. It is the responsibility of the author to make sure that the `from` and `through` values are sensible. I.e.,

        1 <= from <= through <= ncolumns

To set a horizontal line in just one column select `through` equal to `from`.

Note: this macro cannot be used if multiple lines must be set in one row. In those cases the macros `tline, tskip`, and `tendline` should be used.

Instead of using `columnline` in `table`, consider using `tline` in `tbl`.

### 4.2.23: dashes()

Inserts two dashes in teletype font, and prevents them from being expanded.

In html the `attrib` macro is recognized by the `<code>` tag that is used to embed the two dashes.

### 4.2.24: def(macroname)(nrofargs)(redefinition)

Defines `macroname` as a macro, having `nrofargs` arguments, and expanding to `redefinition`. This macro is a shorthand for `DEFINEMACRO`. An error occurs when the macro is already defined. Use `redef()` to unconditionally define or redefine a macro.

### 4.2.25: description(list)

Sets `list` as a description list. Use `dit(item)` to indicate items in the list.

### 4.2.26: dit(itemname)

Starts an item named `itemname` in a description list. The list should be used in `description` macros. With `html` conversions the contents of a description item is separated from the item itself. The `dit` macro only defines the item, and not the description itself. This macro sets the item in bold-face (`strong' font). The macro `itdesc`, available since Yodl 3.05, can be used to defines an item and its description, using its suggested format (i.e., indenting the description relative to the item).

### 4.2.27: eit()

Indicates an item in an enumerated list. The `eit` macro should be used as an argument in `enumeration` macros.

### 4.2.28: ellipsis()

Sets ellipsis (...).

### 4.2.29: em(text)

Sets `text` as emphasized, usually italics.

### 4.2.30: email(address)

In HTML, this macro sets the `address` in a `<a href="mailto=..">` locator. In other output formats, the `address` is sent to the output. The `email` macro is a special case of `url`.

### 4.2.31: enumeration(list)

`enumeration()` starts an enumerated list. Use `eit()` in the list to indicate items in the list.

### 4.2.32: euro()

Sets the euro currency symbol in latex, html, (and possibly sgml and xml). In all other conversions EUR which is the official textual abbreviation (cf. http://ec.europa.eu/euro/entry.html) is written. Note that LaTeX may require latexpackage()(eurosym).

### 4.2.33: evalsymbol(symbol)(expression)

Symbol symbol receives the value resulting from evaluating expression. E.g., if `sym` is a defined symbol, then

        evalsymbol(sym)(SUBSTR(hello world)(3)(2))

assigns the value `lo` to `sym`.

### 4.2.34: fig(label)

This macro is a shorthand for `figure ref(label)` and just makes the typing shorter, as in `see fig(schematic) for ..` See `getfigurestring()` and `setfigurestring()` for the `figure` text.

### 4.2.35: figure(file)(caption)(label)

Sets the picture in `file` as a figure in the current document, using the descriptive text `caption`. The `label` is defined as a placeholder for the figure number and can be used in a corresponding `ref` statement. Note that the `file` must be the filename without extension: By default, Yodl will supply `.gif` when in HTML mode, or `.ps` when in LaTeX mode. Figures in other modes may not (yet) haven been implemented.

When converting to html, this macro uses three attribute-strings (if available). The string pushed first using an attrib-call defines the attributes for its `<figcaption>` html-markup; the string pushed next defines the attributes for its `<img>` html-markup; the string pushed last defines the attributes for its `<figure>` html-markup. The `figure` macro's html output is organized like this:

        <figure -attrib-string pushed last (if any)>
            <img ... -attrib-string pushed last but one>
            <figcaption -attrib-string pushed 2nd to last>
                ...
            </figcaption>
        </figure>

Starting with Yodl 3.07.00 no `alt="Figure # is shown here..."` attribute is defined anymore for the `img` markup: an `alt`-attribute can easily be defined at the last attrib-call, using `getfigurestring()` to obtain `Figure` or its language-specific translation, and `COUNTERVALUE(XXfigurecounter)` to obtain the order-number of the figure shown in the next `figure`-macro call.

### 4.2.36: file(text)

Sets `text` as filename, usually boldface. In html `attrib` macro applies to the `<strong>` tag.

### 4.2.37: findex()

Generate an index entry for LaTex() or texinfo f-indices. Its argument is the index entry. See also the `[cptv]index` macro.

### 4.2.38: footnote(text)

Sets `text` as a footnote, or between parentheses when the output format does not allow footnotes.

### 4.2.39: gagmacrowarning(name name ...)

Prevents the `yodl` program from printing cannot expand possible user macro. E.g., if you have in your document `the file(s) are ..` then you might want to put before that: `gagmacrowarning(file)`. Calls `NOUSERMACRO`.

### 4.2.40: getaffilstring()

Expands to the string that defines the name of Affiliation Information, by default AFFILIATION INFORMATION. Can be redefined for national language support by `setaffilstring()`. Currently, it is relevant only for txt.

### 4.2.41: getauthorstring()

Expands to the string that defines the name of Author Information, by default AUTHOR INFORMATION. Can be redefined for national language support by `setauthorstring()`. Currently, it is relevant only for txt.

### 4.2.42: getchapterstring()

Expands to the string that defines a `chapter' entry, by default Chapter. Can be redefined for national language support by `setchapterstring()`.

### 4.2.43: getdatestring()

Expands to the string that defines the name of Date Information, by default DATE INFORMATION. Can be redefined for national language support by `setdatestring()`. Currently, it is relevant only for txt.

### 4.2.44: getfigurestring()

Returns the string that defines a `figure' text, in captions or in the `fig()` macro. The string can be redefined using the `setfiguretext()` macro.

### 4.2.45: getpartstring()

Expands to the string that defines a `part' entry, by default Part. Can be redefined for national language support by `setpartstring()`.

### 4.2.46: gettitlestring()

Expands to the string that defines the name of Title Information, by default TITLE INFORMATION. Can be redefined for national language support by `settitlestring()`. Currently, it is relevant only for txt.

### 4.2.47: gettocstring()

Expands to the string that defines the name of the table of contents, by default Table of Contents. Can be redefined for national language support by `settocstring()`.

### 4.2.48: htmlcommand(cmd)

Writes `cmd` to the output when converting to html. The `cmd` is not further expanded by Yodl.

### 4.2.49: htmlheadfile(file)

Adds the contents of `file` to the `head` section of an HTML document. The contents of file are not interpreted and should contain plain html text. This option can be useful when large bodies of text, like the contents of `<script>` sections, must be included into the head section of html documents. This macro is only active in the preamble, should only specified once, and is only interpreted for html conversions.

### 4.2.50: htmlheadopt(option)

Adds the literal text `option` to the current information in the `head` section of an HTML document. `Option` may (or: should) contain plain html text. A commonly occurring head option is `link`, defining, e.g., a style sheet. Since that option is frequently used, it has received a dedicated macro: `htmlstylesheet`. When large bodies of html-text must be added to html documents the macro `htmlheadfile` should be used. This macro is only active in the preamble and is only interpreted for html conversions.

### 4.2.51: htmlnewfile()

In HTML output, starts a new file. All other formats are not affected. Note that you must take your own provisions to access the new file; say via links. Also, it's safe to start a new file just befoore opening a new section, since sections are accessible from the clickable table of contents. The HTML converter normally only starts new files prior to a `chapter` definition.

### 4.2.52: htmlstyle(tag)(definition)

Adds a `<style type="text/css"> ... </style>` element to the head section of an HTML document.
Use `htmlstyle` to specify one or more CSS definitions which are eventually inserted at the ellipsis (`...`) in the generic `style` definition shown above. E.g., (using `#rrggbb` to specify a color, where `rr` are two hexadecimal digits specifying the color's red component, `gg` two hexadecimal digits specifying the color's green component, and `bb` two hexadecimal digits specifying the color's blue component) specifying

        htmlstyle(body)(color: #rrggbb; background-color: #rrggbb)
        htmlstyle(h1)(color: blue; text-align: center)
        htmlstyle(h2)(color: green)

results in the element

        <style type="text/css">
            body {color: #rrggbb; background-color: #rrggbb;}
            h1 {color: blue; text-align: center;}
            h2 {color: green;}
        </style>

The macros `htmlheadopt` and `htmlstylesheet` could also be used to put information into the head-section of an HTML document, but `htmlheadopt` is of a much more general nature, while `htmlstylesheet` refers to CSS elements stored in an external file. The macro `attrib` can be used to define inline styles.

The `htmlstyle` macro is only active in the preamble and is only interpreted for html conversions.
Refer to available CSS specifications (cf., http://www.w3schools.com/cssref/ for an overview of how CSS specifications are used, and which CSS specifications are available).

By default the internal style specification
`figure {text-align: center;} img {vertical-align: center;}`
is used. If this is not appropriate, specify `nohtmlimgstyle()` in the preamble.

### 4.2.53: htmlstylesheet(url)

Adds a `<link rel="stylesheet" type="text/css" ...>` element to the head section of an HTML document, using `url` in its `href` field. The argument `url` is not expanded, and should be plain HTML text, without surrounding quotes. The macro `htmlheadopt` can also be used to put information in the head-section of an HTML document, but `htmlheadopt` is of a much more general nature. This macro is only active in the preamble and is only interpreted for html conversions.

### 4.2.54: htmltag(tagname)(start)

Sets `tagname` as a HTML tag, enclosed by `<` and `>`. When `start` is zero, the `tagname` is prefixed with `/`. As not all html tags are available through predefined Yodl-macros (there are too many of them, some are used very infrequently, and you can easily define macros for the tags for which Yodl doesn't offer predefined ones), the `htmltag` macro can be used to handle your own set of macros. In html the `attrib` macro is supported. E.g.,

    attrib(title="World Health Organization")\
        htmltag(abbr)()WHO+htmltag(abbr)(0)

### 4.2.55: ifnewparagraph(truelist)(falselist)

The macro `ifnewparagraph` should be called from the `PARAGRAPH` macro, if defined. It will insert `truelist` if a new paragraph is inserted, otherwise `falselist` is inserted (e.g., following two consecutive calls of PARAGRAPH). This macro can be used to prevent outputting multiple blank lines.

### 4.2.56: includefile(file)

Includes `file`. The default extension `.yo` is supplied if necessary.

Since Yodl version 3.00.0 Yodl's default file inclusion behavior has changed. The current working directory no longer remains fixed at the directory in which Yodl is called, but is volatile, changing to the directory in which a yodl-file is located. This has the advantage that Yodl's file inclusion behavior now matches the way C's `#include` directive operates. The originally implemented file inclusion behavior is used when Yodl's `-L` (`--legacy-include`) option is used.

### 4.2.57: includeverbatim(file)

Include `file` into the output. No processing is done, `file` should be in preformatted form, e.g.:

    whenhtml(includeverbatim(foo.html))

### 4.2.58: it()

Indicates an item in an itemized list. Items in `it` macros are arguments of `itemization` macros.

### 4.2.59: itdesc(itemname)(contents)

Starts an item and its description in a description list. Its name is `itemname`, the contents of the item is defined by `contents`. The `itemname` is defined by using the `dit` macro.

With `html` conversions the contents are surrounded by `<dd>` and `</dd>` tags, resulting in contents which are indented relative to the itemname. When the `attrib` macro is used it is applied to the itemname (`dt`-tags).

With other conversions the `contents` are quoted (as if using `quote(contents)`).

### 4.2.60: itemization(list)

Sets `list` as an itemizationd list. Use `it()` to indicate items in the list.

### 4.2.61: kindex()

Generate an index entry for LaTex() or texinfo k-indices. Its argument is the index entry. See also the `[cfptv]vindex` macro.

### 4.2.62: label(labelname)

Defines `labelname` as an anchor for a `link` command, or to stand for the last numbering of a section or figure in a `ref` command.

### 4.2.63: langle()

Character <

### 4.2.64: languagedutch()

Defines the Dutch-language specific headers. Active this macro via setlanguage(dutch).

### 4.2.65: languageenglish()

Defines the English-language specific headers. Active this macro via setlanguage(english).

### 4.2.66: languageportugese()

Defines the Portugese-language specific headers. Active this macro via setlanguage(portugese).

### 4.2.67: LaTeX()

The LaTeX symbol.

### 4.2.68: latexaddlayout(arg)

This macro is provided to add Yodl-interpreted text to your own LaTeX layout commands. The command is terminated with an end-of-line. See also the macro `latexlayoutcmds()`

### 4.2.69: latexcommand(cmd)

Writes `cmd` plus a white space to the output when converting to LaTeX. The `cmd` is not further expanded by Yodl.

### 4.2.70: latexdocumentclass(class)

Forces the LaTeX `\documentclass{...}` setting to `class`. Normally the class is defined by the macros `article`, `report` or `book`. This macro is an escape route in case you need to specify your own document class for LaTeX. This option is a modifier and must appear before the `article`, `report` or `book` macros.

### 4.2.71: latexlayoutcmds(NOTRANSs)

This macro is provided in case you want to put your own LaTeX layout commands into LaTeX output. The `NOTRANSs` are pasted right after the `\documentclass` stanza. The default is, of course, no local LaTeX commands. Note that this macro does not overrule my favorite LaTeX layout. Use `nosloppyhfuzz()` and `standardlayout()` to disable my favorite LaTeX layout.

### 4.2.72: latexoptions(options)

Set latex options: `documentclass[options]`. This command must appear before the document type is stated by `article`, `report`, etc..

### 4.2.73: latexpackage(options)(name)

Include latex package(s), a useful package is, e.g., `epsf`. This command must appear before the document type is stated by `article`, `report`, etc..

### 4.2.74: lchapter(label)(title)

Starts a new chapter in books or reports, setting a label at the beginning of the chapter.

### 4.2.75: letter(language)(date)(subject)(opening)(salutation)(author)

Starts a letter written in the indicated language. The date of the letter is set to `date', the subject of the letter will be `subject'. The letter starts with `opening'. It is based on the `letter.cls' document class definition. The macro is available for LaTeX only. Preamble command suggestions:

- `latexoptions(11pt)`
- `a4enlarged()`
- `letterreplyto(name)(address)(postalcode/city)`
- `letterfootitem(phone)(number)`, maybe e-mail too.
- `letteradmin(yourdate)(yourref)`
- `letterto(addressitem)`. Use a separate `letterto()` macro call for each new line of the address.

### 4.2.76: letteraddenda(type)(value)

Adds an addendum at the end of a letter. `type' should be `bijlagen', `cc' or `ps'.

### 4.2.77: letteradmin(yourdate)(yourref)

Puts `yourletterfrom' and `yourreference' elements in the letter. If left empty, two dashes are inserted.

### 4.2.78: letterfootitem(name)(value)

Puts a footer at the bottom of letter-pages. Up to three will usually fit. LaTeX only.

### 4.2.79: letterreplyto(name)(address)(zip city)

Defines the `reply to' address in LaTeX or txt-letters.

### 4.2.80: letterto(element)

Adds `element' as an additional line to the address in LaTeX letters.

### 4.2.81: link(description)(labelname)

In HTML output a clickable link with the text `description` is created that points to the place where `labelname` is defined using the `label` macro, and `attrib` macro applies to the `<a>` tag. Using `link` is similar to `url`, except that a hyperlink is set pointing to a location in the same document. For output formats other than HTML, only the `description` appears.

### 4.2.82: lref(description)(labelname)

This macro is a combination of the `ref` and `link` macros. In HTML output a clickable link with the text `description` and the label value is created that points to the place where `labelname` is defined using the `label` macro, and `attrib` macro applies to the `<a>` tag. For output formats other than HTML, only the `description` and the label value appears.

### 4.2.83: lsect(label)(title)

Starts a new section, setting a label at the beginning of the section. In html `attrib` macro applies to the `<h2>` tag.

### 4.2.84: lsubsect(label)(title)

Starts a new subsection. Other sectioning commands are `subsubsect` and `subsubsubsect`. A label is added just before the subsection. In html `attrib` macro applies to the `<h3>` tag.

### 4.2.85: lsubsubsect(label)(title)

Starts a sub-subsection, a label is added just before the section In html `attrib` macro applies to the `<h4>` tag.

### 4.2.86: lsubsubsubsect(label)(title)

Starts a sub-sub-sub section. This level of sectioning is not numbered, in contrast to `higher' sectionings. A label is added just before the subsubsubection.

### 4.2.87: lurl(locator)

An url described by its Locator. For small urls with readable addresses.

### 4.2.88: mailto(address)

Defines the default `mailto` address for HTML output. Must appear before the document type is stated by `article`, `report`, etc..

### 4.2.89: makeindex()

Make index for latex.

### 4.2.90: mancommand(cmd)

Writes `cmd` to the output when converting to man. The `cmd` is not further expanded by Yodl.

### 4.2.91: manpage(title)(section)(date)(source)(manual)

Starts a manual page document. The `section` argument must be a number, stating to which section the manpage belongs to. Most often used are commands (1), file formats (5) and macro packages (7). The sectioning commands in a manpage are not `(n)sect` etc., but `manpage...()`. The first section must be the `manpagename`, the last section must be the `manpageauthor`. The standard manpage for section 1 contains the following sections (in the given order): `manpagename`, `manpagesynopsis`, `manpagedescription`, `manpageoptions`, `manpagefiles`, `manpageseealso`, `manpagediagnostics`, `manpagebugs`, `manpageauthor`. Optional extra sections can be added with `manpagesection`. Standard manpageframes for several manpagesections are provided in `/usr/local/share/yodl/manframes`. `Yodl` manual pages can be converted to `groff, html`, or plain ascii text formats.

### 4.2.92: manpageauthor()

Starts the AUTHOR entry in a `manpage` document. Must be the last section of a `manpage`.

### 4.2.93: manpagebugs()

Starts the BUGS entry in a `manpage` document.

### 4.2.94: manpagedescription()

Starts the DESCRIPTION entry in a `manpage` document.

### 4.2.95: manpagediagnostics()

Starts the DIAGNOSTICS entry in a `manpage` document.

### 4.2.96: manpagefiles()

Starts the FILES entry in a `manpage` document.

### 4.2.97: manpagename(name)(short description)

Starts the NAME entry in a `manpage` document. The short description is used by, e.g., the `whatis` database.

### 4.2.98: manpageoptions()

Starts the OPTIONS entry in a `manpage` document.

### 4.2.99: manpagesection(SECTIONNAME)

Inserts a non-required section named `SECTIONNAME` in a `manpage` document. This macro can be used to augment `standard' manual pages with extra sections, e.g., EXAMPLES. Note that the name of the extra section should appear in upper case, which is consistent with the normal typesetting of manual pages.

### 4.2.100: manpageseealso()

Starts the SEE ALSO entry in a `manpage` document.

### 4.2.101: manpagesynopsis()

Starts the SYNOPSIS entry in a `manpage` document.

### 4.2.102: manttquoted(onOff)

With man-conversions arguments of tt macros are displayed as normal text. To enhance their visibility arguments of tt macros may be quoted, in which case they are surrounded by backtics and normal quotes. By default arguments of tt macros are not quoted. Quotation is used after calling `manttquoted(1)`, and is suppressed after calling `manttquoted(0)`. The macro is only active when converting to man.

### 4.2.103: mbox()

Unbreakable box in LaTeX. Other formats may have different opitions on our unbreakable boxex.

### 4.2.104: metaC(text)

Put a line comment in the output.

### 4.2.105: metaCOMMENT(text)

Write format-specific comment to the output.

### 4.2.106: mscommand(cmd)

Writes `cmd` to the output when converting to ms. The `cmd` is not further expanded by Yodl.

### 4.2.107: nbsp(count)

Inserts `count` `non-breaking space' characters into the generated output; i.e., the space character is not optimized away. If the argument list is empty one non-breaking space is inserted.

### 4.2.108: nchapter(title)

Starts a chapter (in a `book` or `report`) without generating a number before the title and without placing an entry for the chapter in the table of contents. In html `attrib` macro applies to the `<h1>` tag.

### 4.2.109: nemail(name)(address)

Named email. A more consistent naming for url, lurl, email and nemail would be nice.

### 4.2.110: nl()

Forces a newline; i.e., breaks the current line in two.

### 4.2.111: nodeprefix(text)

Prepend text to node names, e.g.

    nodeprefix(LilyPond) sect(Overview)

Currently used in texinfo descriptions only.

### 4.2.112: nodeprefix(text)

Prepend text to node names, e.g.

    nodeprefix(LilyPond) sect(Overview)

Currently used in texinfo descriptions only.

### 4.2.113: nodetext(text)

Use text as description for the next node, e.g.

    nodetext(The GNU Music Typesetter)chapter(LilyPond)

Currently used in texinfo descriptions only.

### 4.2.114: nohtmlfive()

Starting yodl 3.05 html-conversions by default use html5. This can be suppressed (in favor of using html4) by calling this macro. This macro merely suppresses writing the initial `<!DOCTYPE html>` to generated html files; it is only active in the preamble and is only interpreted for html conversions.

### 4.2.115: nohtmlimgstyle()

By default html-pages specify
`(<style type="text/css" img {vertical-align: bottom;}></style>)`
This macro suppresses this `img` CSS style specification. This macro is only active in the preamble and is only interpreted for html conversions.

### 4.2.116: nop(text)

Expand to text, to avoid spaces before macros e.g.: a2. Although a+sups(2) should have the same effect.

### 4.2.117: nosloppyhfuzz()

By default, LaTeX output contains commands that cause it to shut up about hboxes that are less than 4pt overfull. When `nosloppyhfuzz()` appears before stating the document type, LaTeX complaints are `vanilla'.

### 4.2.118: notableofcontents()

Prevents the generation of a table of contents. This is default in, e.g., `manpage` and `plainhtml` documents. When present, this option must appear before stating the document type with `article`, `report` etc..

### 4.2.119: notitleclearpage()

Prevents the generation of a `clearpage()` instruction after the typesetting of title information. This instruction is default in all non `article` documents. When present, must appear before stating the document type with `article`, `book` or `report`.

### 4.2.120: notocclearpage()

With the LaTeX converter, no `clearpage()` instruction is inserted immediately beyond the document's table of contents. The `clearpage()` instruction is default in all but the `article` document type. When present, must appear before stating the document type with `article`, `book` or `report`. With other converters than the LaTeX converter, it is ignored.

### 4.2.121: notransinclude(filename)

Reads filename and inserts it literally in the text not subject to macro expansion or character translation. No information is written either before or after the file's contents, not even a newline.

### 4.2.122: noxlatin()

When used in the preamble, the LaTeX converter disables the inclusion of the file `xlatin1.tex`. Normally this file gets included in the LateX output files to ensure the conversion of high ASCII characters (like é) to LaTeX-understandable codes. (The file `xlatin1.tex` comes with the `Yodl` distribution.)

### 4.2.123: nparagraph(title)

Starts a non-numbered paragraph (duh, corresponds to subparagraph in latex).

### 4.2.124: npart(title)

Starts a part in a `book` document, but without numbering it and without entering the title of the part in the table of contents. In html `attrib` macro applies to the `<h1>` tag.

### 4.2.125: nsect(title)

Starts a section, but does not generate a number before the `title` nor an entry in the table of contents. Further sectioning commands are `nsubsect`, `nsubsubsect` and `nsubsubsubsect`. In html `attrib` macro applies to the `<h2>` tag.

### 4.2.126: nsubsect(title)

Starts a non-numbered subsection. In html the `attrib` macro applies to the `<h3>` tag.

### 4.2.127: nsubsubsect(title)

Starts a non-numbered sub-sub section. In html `attrib` macro applies to the `<p>` tag.

### 4.2.128: nsubsubsect(title)

Starts a non-numbered sub-subsection.

### 4.2.129: paragraph(title)

Starts a paragraph. This level of sectioning is not numbered, in contrast to `higher' sectionings (duh, corresponds to subparagraph in latex). In html `attrib` macro applies to the `<p>` tag.

### 4.2.130: part(title)

Starts a new part in a `book` document. In html `attrib` macro applies to the `<h1>` tag.

### 4.2.131: pindex()

Generate an index entry for LaTex() or texinfo p-indices. Its argument is the index entry. See also the `[cftv]index` macro.

### 4.2.132: plainhtml(title)

Starts a document for only a plain HTML conversion. Not available in other output formats. Similar to `article`, except that an author- and date field are not needed.

### 4.2.133: printindex()

Make index for texinfo (?).

### 4.2.134: quote(text)

Sets the text as a quotation. Usually, the text is indented, depending on the output format. In html the `attrib` macro is recognized by the `<blockquote>` tag.

### 4.2.135: rangle()

Inserts the right angle character (>).

### 4.2.136: redef(macro)(nrofargs)(redefinition)

Defines macro `macro` to expand to `redefinition`. Similar to `def`, but any pre-existing definition is overruled. Use `ARG`x in the redefinition part to indicate where the arguments should be pasted. E.g., `ARG1` places the first argument, `ARG2` the second argument, etc...

### 4.2.137: redefinemacro(macro)(nrofargs)(redefinition)

Defines macro `macro` to expand to `redefinition`. Similar to `def`, but any pre-existing definition is overruled. Use `ARG`x in the redefinition part to indicate where the arguments should be pasted. E.g., `ARG1` places the first argument, `ARG2` the second argument, etc... This commands is actually calling redef().

### 4.2.138: ref(labelname)

Sets the reference for `labelname`. Use `label` to define a label.

### 4.2.139: report(title)(author)(date)

Starts a report type document. The top-level sectioning command in a report is `chapter`. In html the way the headings are displayed can be tuned using CSS id selector specifications: the title has `id="title"`, the author `id="author"`, and the date `id="date"`.

### 4.2.140: roffcmd(dotcmd)(sameline)(secondline)(thirdline)

Sets a t/nroff command that starts with a dot, on its own line. The arguments are: `dotcmd` - the command itself, e.g., `.IP`; `sameline` - when not empty, `sameline` is set on the same line, following the `dotcmd`; `secondline` - when not empty, is set on the next line; `thirdline` - when not empty, is set on the third line. Note: `dotcmd` and `thirdline` are not further expanded by `Yodl`, the other arguments are.

### 4.2.141: row(contents)

The argument `contents` may contain a man-page alignment specification (only one specification can be entered per row), using `setmanalign()`. If omitted, the standard alignment is used. Furthermore it contains the contents of the elements of the row, using `cell()` or `cells()` macros. If `cells()` is used, `setmanalign()` should have been used too. In this macro call only the `cell()`, `cells()` and `setmanalign()` macros should be called. Any other macro call may produce unexpected results.

The `row` macro defines a counter `XXcol` that can be inspected and is incremented by predefined macros adding columns to a row. The counter is initially 0. Predefined macros adding columns to a row add the number of columns they add to the row inserting the contents of those columns. These macros rely on the correct value of this counter and any user-defined macros adding columns to table rows should correctly update `XXcol`. In html `attrib` macro applies to the `<tr>` tag.

Instead of using `row` in `table`, consider using `tr` in `tbl`.

### 4.2.142: rowline()

Sets a horizontal line over the full width of the table. See also the `columnline` macro. Use `rowline` instead of a `row` macro call to provide a table with a horizontal line-separator.

Instead of using `rowline` consider using `tline` in a `tbl` argument.

### 4.2.143: sc(text)

Set `text` in the tt (code) font, using small caps. In html the `attrib` macro is not supported, while the code section is embedded in a `<div style="font-size: 90%">` section.

### 4.2.144: sect(title)

Starts a new section. In html the `attrib` macro is recognized by the `<h2>` tag.

### 4.2.145: setaffilstring(name)

Defines `name` as the `affiliation information' string, by default AFFILIATION INFORMATION. E.g., after `setaffilstring(AFILIACION)`, `Yodl` outputs this Spanish string to describe the affiliation information. Currently, it is relevant only for txt.

### 4.2.146: setauthorstring(name)

Defines `name` as the `Author information' string, by default AUTHOR INFORMATION. E.g., after `setauthorstring(AUTOR)`, `Yodl` outputs this portuguese string to describe the author information. Currently, it is relevant only for txt.

### 4.2.147: setchapterstring(name)

Defines `name` as the `chapter' string, by default Chapter. E.g., after `setchapterstring(Hoofdstuk)`, `Yodl` gains some measure of national language support for Dutch. Note that LaTeX support has its own NLS, this macro doesn't affect the way LaTeX output looks.

### 4.2.148: setdatestring(name)

Defines `name` as the `date information' string, by default DATE INFORMATION. E.g., after `setdatestring(DATA)`, `Yodl` outputs this portuguese string to describe the date information. Currently, it is relevant only for txt.

### 4.2.149: setfigureext(name)

Defines the `name` as the `figure' extension. The extension should include the period, if used. E.g., use setfigureext(.ps) if the extensions of the figure-images should end in `.ps`

### 4.2.150: setfigurestring(name)

Defines the `name` as the `figure' text, used e.g. in figure captions. E.g., after `setfigurestring(Figuur)`, Yodl uses Dutch names for figures.

### 4.2.151: sethtmlfigureext(ext)

Defines the filename extension for HTML figures, defaults to `.jpg`. Note that a leading dot must be included in `ext`. The new extension takes effect starting with the following usage of the `figure` macro. It is only active in html, but otherwise acts identically as setfigureext().

See also the `setlatexfigureext` macro.

### 4.2.152: htmlmetacharset(meta-charset)

Adds `<meta charset="meta-charset">` to the head of html documents. By default `<meta charset="UTF-8">` is used. This macro is only active in the preamble and is only interpreted for html conversions.

### 4.2.153: setincludepath(name)

Sets a new value of the include-path specification used when opening .yo files. A warning is issued when the path specification does not include a .: element. Note that the local directory may still be an element of the new include path, as the local directory may be the only or the last element of the specification. For these eventualities the new path specification is not checked.

### 4.2.154: setlanguage(name)

Installs the headers specific to a language. The argument must be the name of a language, whose headers have been set by a corresponding languageXXX() call. For example: languagedutch(). The language macros should set the names of the headers of the following elements: table of contents, affiliation, author, chapter, date, figure, part and title

### 4.2.155: setlatexalign(alignment)

This macro defines the table alignment used when setting tables in LaTeX. Use as many `l` (for left-alignment), `r` (for right alignment), and `c` (for centered-alignment) characters as there are columns in the table. See also `table()`.

Instead of using the `table` macro consider using the `tbl` macro.

### 4.2.156: setlatexfigureext(ext)

Defines the filename extension for encapsulated PostScript figures in LaTeX, defaults to `.ps`. The dot must be included in t new extension `ext`. The new extension takes effect starting with a following usage of the `figure` macro. It is only active in LaTeX, but otherwise acts identically as setfigureext().

See also the `sethtmlfigureext` macro.

### 4.2.157: setlatexverbchar(char)

Set the char used to quote LaTeX `\verb` sequences

### 4.2.158: setmanalign(alignment)

This macro defines the table alignment in the context of the `table` macro, and is used when setting tables in man-pages (see tbl(1)).

Use as many `l` (for left-alignment), `r` (for right alignment), and `c` (for centered-alignment) characters as there are columns in the table.

Use `s` to indicate that the column to its left is combined (spans into) the current column. Use this specification when cells spanning multiple columns must be defined.

Each row in a table which must be convertible to a manpage may be preceded by its own `setmanalign` call.

Note that neither `rowline` nor `columnline` requires `setmanalign` specifications, as these macros define rows by themselves. It is the responsibility of the author to ensure that the number of alignment characters is equal to the number of columns of the table.

Instead of using the `table` macro consider using the `tbl` macro.

### 4.2.159: setpartstring(name)

Defines `name` as the `part' string, by default Part. E.g., after `setpartstring(Teil)`, Yodl identifies parts in the German way. Note that LaTeX output does its own national language support; this macro doesn't affect the way LaTeX output looks.

### 4.2.160: setrofftab(x)

Sets the character separating items in a line of input data of a `roff` (manpage) table. By default it is set to `~`. This separator is used internally, and needs only be changed (into some unique character) if the table elements themselves contain `~` characters.

This macro can be used in the context of the `table` and `tbl` macros.

### 4.2.161: setrofftableoptions(optionlist)

Set options used for man-conversion, as used by the `tbl` and `table` macros. By default no options are used. Multiple options should be separated by blanks. From the tbl(1) manpage, the following options are available:

- `center` Centers the table; default is left-justified. In the context of the `tbl` macro this is implied when the `tbl` macro is specified as argument of the `center` macro.
- `expand` Makes the table as wide as the current line length
- `box` Encloses the table in a box
- `allbox` Encloses each item of the table in a box

See also `setrofftab` which is used to set the character separating items in a line of input data.

### 4.2.162: settitlestring(name)

Defines `name` as the `title information' string, by default TITLE INFORMATION. E.g., after `settitlestring(TITEL)`, `Yodl` outputs this Dutch string to describe the title information. Currently, it is relevant only for txt.

### 4.2.163: settocstring(name)

Defines `name` as the `table of contents' string, by default Table of Contents. E.g., after `settocstring(Inhalt)`, `Yodl` identifies the table of contents in the German way. Note that LaTeX output does its own national language support; this macro doesn't affect the way LaTeX output looks.

### 4.2.164: sgmlcommand(cmd)

Writes `cmd` to the output when converting to sgml. The `cmd` is not further expanded by Yodl.

### 4.2.165: sgmltag(tag)(onoff)

Similar to `htmltag`, but used in the SGML converter.

### 4.2.166: sloppyhfuzz(points)

By default, LaTeX output contains commands that cause it to shut up about hboxes that are less than 4pt overfull. When `sloppyhfuzz()` appears before stating the document type, LaTeX complaints occur only if hboxes are overfull by more than `points`.

### 4.2.167: standardlayout()

Enables the default LaTeX layout. When this macro is absent, then the first lines of paragraphs are not indented and the space between paragraphs is somewhat larger. The `standardlayout()` directive must appear before stating the document type as `article`, `report`, etc..

### 4.2.168: strong(contents)

In html and xml the `contents` are set between `<strong>` and `</strong>` tags. In html `attrib` macro applies to the `<strong>` tag.

### 4.2.169: subs(text)

Sets text in subscript in supporting formats. In html the `attrib` macro is recognized by the `<sub>` tag.

For superscripting, the `sups` macro can be used.

### 4.2.170: subsect(title)

Starts a new subsection. Other sectioning commands are `subsubsect` and `subsubsubsect`. In html `attrib` macro applies to the `<h3>` tag.

### 4.2.171: subsubsect(title)

Starts a sub-subsection. In html `attrib` macro applies to the `<h4>` tag.

### 4.2.172: subsubsubsect(title)

Starts a sub-sub-sub-subsection. This level of sectioning is not numbered, in contrast to `higher' sectionings.

### 4.2.173: sups(text)

Sets text in superscript in supporting formats In html the `attrib` macro is recognized by the `<sup>` tag.

For subscripting, the `subs` macro can be used.

### 4.2.174: table(nColumns)(alignment)(Contents)

Instead of using the `table` macro, consider using the `tbl` macro.

The `table()`-macro defines a table. Its first argument specifies the number of columns in the table.

Its second argument specifies the (standard) alignment of the information within the cells as used by LaTeX or man/ms. Use `l` for left-alignment, `c` for centered-alignment and `r` for right alignment.

Its third argument defines the contents of the table which are the rows, each containing column-specifications and optionally man/ms alignment definitions for this row.

See also the `tableatt` macro and the specialized `setmanalign()` macro.

### 4.2.175: tableatt(nColumns)(alignment)(Contents)

Instead of using the `tableatt` macro, consider using the `tbl` macro.

The `tableatt()`-macro defines a table. The last `attrib` call that was specified before using the `tableatt()`-macro is used to specify html attributes for the table. E.g., to center a table in html use

        attrib(style="margin-left:auto;margin-right:auto;")
        tableatt(...)

The macro's first argument specifies the number of columns in the table. Its second argument specifies the (standard) alignment of the information within the cells as used by LaTeX or man/ms. Use `l` for left-alignment, `c` for centered-alignment and `r` for right alignment. Its third argument defines the contents of the table which are the rows, each containing column-specifications and optionally man/ms alignment definitions for this row.

See also the `table` macro and the specialized `setmanalign()` macro.

### 4.2.176: tac(alignment)(contents)

This macro is one of the four macros that can be used to define column contents of rows of tables defined by the `tbl` macro. Alternatively, `tc, tnc`, and `tnac` can be used.

The `tac` macro is used as argument of the `tr` macro. The cell's alignment is defined by the `alignment` specification, containing at most two alignment specifications: a horizontal alignment (one of c, l, r (centered, left-aligned, right-aligned)) and a vertical alignment (one of t, b (vertical top- and bottom-alignment)) (not all conversion types may support all alignment types, e.g., man-conversion does not support vertical bottom alignment). Specifications other than c, l, r, b, and t and specifications beyond the second one are ignored. The result of specifying conflicting alignment types (e.g., `lr` or `tb`) is not defined.

When converting to `man`, if the table's contents should span multiple rows, then a groff/troff(1) text block must be used. Since most tables do not use this, a text block is not generated by default. To actually wrap the contents of column elements in a text block while converting to `man` prefix the first text block requiring a text-block wrapping by `twrap(1)`, and end the last text block requiring a text-block wrapping by `wrap(0)`.

The `tao` macro can be used to overrule the specified alignment for a specific conversion type.

The macro `tac` recognizes `attrib`.

### 4.2.177: tao(type)(specification)

This macro is used inside the `tbl` macro to override the alignment specification that would otherwise be used for the next table element. It is only active for the next `tc, tnc, tac,` or `tnac` call. Its first argument defines the conversion type for which the override should be used, its second argument defines the alignment specification to use.

Here are some examples:

    tbl(lr)(
        tr(
            tc(left aligned)
            tc(right aligned)
        )
        tr(
            tao(html)(c)
              tc(left aligned, centered with html)
            tao(latex)(l)
            tao(man)(l)
              tac(c)(centered, latex and man: left aligned)
        )
    )

Further details about the `tao` macro are provided in the yodltables(7) man-page.

### 4.2.178: tbl(align)(contents)

The `tbl` macro refines the more basic `table` macro. It was named after the tbl(1) table formatting program used with troff(1) documents.

The `tbl` macro currently is available for `html, man/ms, latex` and `txt` conversions.

Its first argument defines the alignment of the information in the table's columns, and is used by all conversions except `txt`. Use `l` for left-alignment, `c` for centered-alignment and `r` for right-alignment. Individual cells of the table may override these default settings using the macros `tac` and `tnac`.

Its second argument defines the contents of the table consisting of rows (using `tr`), and horizontal lines (using `tline`), which may extend over the full table width or may cover one or more individual columns. With `txt` conversion rough approximations of horizontal lines are used.

Tables defined by the `tbl` macro are centered (pseudo centering (8 space characters) is used for `txt` conversion) when used as argument of the `center` macro.

See also the `tao` macro for information about how to realize specific alignments for specific conversion types.

When defining `tbl` tables it is advised to clearly layout the table specification. To avoid inadvertently introducing new lines lines should end in a backslash (or The macro `tbl` recognizes `attrib`.

### 4.2.179: tc(contents)

This macro is one of the four macros that can be used to define column contents of rows of tables defined by the `tbl` macro. Alternatively, `tnc, tac`, and `tnac` can be used.

The `tc` macro is used as argument of the `tr` macro. Its order within a row defines its type attribute, using the alignment specification defined by the first argument of the `tbl` call. E.g., if `tbl(clr)(...)` was used, then the contents of the first `tc` call in a `tr` is centered in the table's first column; the contents of the second `tc` call is left-aligned in the table's second column; and the contents of the third `tc` call is right-aligned in the table's third column.

When converting to `man`, if the table's contents should span multiple rows, then a groff/troff(1) text block must be used. Since most tables do not use this, a text block is not generated by default. To actually wrap the contents of column elements in a text block while converting to `man` prefix the first text block requiring a text-block wrapping by `twrap(1)`, and end the last text block requiring a text-block wrapping by `wrap(0)`.

The `tao` macro can be used to overrule the default alignment specification for a specific conversion type.

The macro `tc` recognizes `attrib`.

### 4.2.180: tcell(text)

Roff helper to set a table text-cell, i.e., a paragraph. For LaTeX special table formatting p{} should be used.

When using the `tbl` macro for defining tables the `twrap` macro can be used to set table elements in text-blocks (i.e., enclosing text, possibly containing newlines in `T{` and `T}` sequences).

### 4.2.181: telycommand(cmd)

Writes `cmd` to the output when converting to tely. The `cmd` is not further expanded by Yodl.

### 4.2.182: TeX()

The TeX symbol.

### 4.2.183: texinfocommand(cmd)

Writes `cmd` to the output when converting to texinfo. The `cmd` is not further expanded by Yodl.

### 4.2.184: tindex()

Generate an index entry for LaTex() or texinfo t-indices. Its argument is the index entry. See also the `[cfpv]index` macro.

### 4.2.185: titleclearpage()

Forces a new page (using `clearpage`) following the title of a document. This is already the default in books and reports, but can be overruled using `notitleclearpage`. When present, it must appear in the preamble, i.e., before the document type is stated as article, book or report.

### 4.2.186: tline(beginNr)(endNr)

This macro is used to insert a horizontal line spanning one or more columns of a table defined by the `tbl` macro.

If `endNr` is not specified, and the `tline` call does not follow a previous `line` call in which `endNr` was specified, then a horizontal line spanning the full width of the table is defined (except when converting to plain text in which case a line of `beginNr` - (minus) characters is written; if `beginNr` is not specified then a line of 60 - characters is written).

If `endNr` is not specified, but the `tline` call follows previous `tline` calls that did specify `endNr` then the current row is ended.

If `endNr` is specified, then a horizontal line is set, starting at column number `beginNr` continuing through column number `endNr`. Note that these are numbers, not offsets: `beginNr` should be at least 1, `endNr` must at least be equal to `beginNr` and should be at most equal to the number of columns in the table. The `beginNr` values of subsequent `tline` calls refer to the same row as the first `tline` call, and must exceed `endNr` of the previous `tline` call.

Examples:

        tline()()       sets a line spanning the full table width
        tline(1)(1)     sets a line in column 1
        tline(3)(4)     sets another line in column 3 and 4
        tline()()       ends the previous line
        tline()()       sets a line spanning the full table width

### 4.2.187: tnac(nCells)(alignment)(contents)

This macro is one of the four macros that can be used to define column contents of rows of tables defined by the `tbl` macro. Alternatively, `tc, tac`, and `tnc` can be used.

The `tnac` macro is used as argument of the `tr` macro. Its first argument defines the number of columns spanned by the contents (2nd argument) of the `tnc` macro.

The cell's alignment is defined by the macro's second (`alignment`) specification, containing at most two alignment specifications: a horizontal alignment (one of c, l, r (centered, left-aligned, right-aligned)) and a vertical alignment (one of t, b (vertical top- and bottom-alignment)) (not all conversion types may support all alignment types). Specifications other than c, l, r, b, and t and specifications beyond the second one are ignored. The result of specifying conflicting alignment types (e.g., `lr` or `tb`) is not defined.

When converting to `man`, if the table's contents should span multiple rows, then a groff/troff(1) text block must be used. Since most tables do not use this, a text block is not generated by default. To actually wrap the contents of column elements in a text block while converting to `man` prefix the first text block requiring a text-block wrapping by `twrap(1)`, and end the last text block requiring a text-block wrapping by `wrap(0)`. Multiple rows in a text block are top-aligned with left and righ neighboring cells.

The `tao` macro can be used to overrule the default alignment specification for a specific conversion type.

The macro `tnac` recognizes `attrib`.

### 4.2.188: tnc(nCells)(contents)

This macro is one of the four macros that can be used to define the column contents of rows of tables that are defined by the `tbl` macro. Alternatively, `tc, tac`, and `tnac` can be used.

The `tnc` macro is used as argument to the `tr` macro. Its first argument defines the number of columns spanned by the contents (2nd argument) of the `tnc` macro. The contents are centered in the `nCells` columns.

When converting to `man`, if the table's contents should span multiple rows, then a groff/troff(1) text block must be used. Since most tables do not use this, a text block is not generated by default. To actually wrap the contents of column elements in a text block while converting to `man` prefix the first text block requiring a text-block wrapping by `twrap(1)`, and end the last text block requiring a text-block wrapping by `wrap(0)`. Multiple rows in a text block are top-aligned with left and righ neighboring cells.

The `tao` macro can be used to overrule the default alignment specification for a specific conversion type.

The macro `tc` recognizes `attrib`.

### 4.2.189: tocclearpage()

With the LaTeX converter, a `clearpage()` directive if inserted, immediately following the document's table of contents. This is already the default in all but the `article` document type, but it can be overruled by `notocclearpage()`. When present, it must appear in the preamble; i.e., before the document type is stated with `article`, `book` or `report`. With other converters than the LaTeX converter, it is ignored.

### 4.2.190: tr(contents)

This macro defines the rows of a table that is defined by the `tbl` macro.

The macro `tr` expects one argument: the contents of the row, defining the row's column elements. It is not used for defining a (partial) horizontal line: to set horizontal lines in a table defined by the `tbl` macro use the macro `tline`.

Normally the contents of the columns in a (`tr`) row is defined by of one or more calls to the macros `tc, tac, tnc,` and/or `tnac`.

The macro `tr` recognizes `attrib`.

### 4.2.191: tt(text)

Sets `text` in teletype font, and prevents it from being expanded. When converting to man, `text` is surrounded by a backtick and a single quote character.

For unbalanced parameter lists, use `CHAR(40)` to get `(` and `CHAR(41)` to get `)`.

The `tt` macro does interpret character tables as well as any `SUBST` definitions. This is usually what is intended. In situations where this is unwelcome the `ttbegin` and `ttend` pair of macros can be used, between which the builtin commands `PUSHSUBST, POPSUBST, NOEXPAND` and/or `NOTRANS` can be used. E.g., to clearly show two hyphens in LaTeX teletype font use

        ttbegin()--ttend()

rather than

        tt(--)

Likewise, use `ttbegin` and `ttend` if the teletype text contains accented letters like ë. To set this in teletype font use `ttbegin()\"``e+ttend()`.

With html conversions the `attrib` macro applies to the `<code>` tag.

With man conversions the arguments of tt macros can be quoted. See the `manttquoted` macro for details.

### 4.2.192: ttbegin()

Initiates text set in teletype font. Following the text to set in teletype font a `ttend()` macro should be called.

Usually the `tt` macro can be used instead of the `ttbegin` -- `ttend` combination. However, `tt` interprets character tables as well as `SUBST` definitions. In situations where this is unwelcome the `ttbegin` and `ttend` pair of macros can be used, between which builtin commands like `PUSHSUBST, POPSUBST, NOEXPAND` and/or `NOTRANS` can be used.

In html the `attrib` macro applies to the `<code>` tag.

### 4.2.193: ttend()

Ends text set in teletype font following `ttbegin`. Refer to the `ttbegin` macro's description for details.

### 4.2.194: twrap(value)

Used for man/ms conversions only: when called with a non-zero argument before using the `tc, tnc, tac`, and `tnac` macros then their contents are wrapped in text blocks (`T{ ... T}` blocks). To end the wrapping `twrap(0)` must be called. E.g., in the following row-definition the contents of columns three and four are set in T-blocks when converting to man/ms:

        tr(tc(one)tc(two)twrap(1)tc(one)tc(two)twrap(0))

### 4.2.195: txtcommand(cmd)

Writes `cmd` to the output when converting to txt. The `cmd` is not further expanded by Yodl.

### 4.2.196: url(description)(locator)

In LaTeX documents the `description` is sent to the output. For HTML, a link is created with the descriptive text `description` and pointing to `locator`. The `locator` should be the full URL, including service; e.g, `http://www.icce.rug.nl`, but excluding the double quotes that are necessary in plain HTML. Use the macro `link` to create links within the same document. For other formats, something like description [locator] will appear. In html `attrib` macro applies to the `<a>` tag.

### 4.2.197: verb(text)

Sets `text` in verbatim mode: not subject to macro expansion or character table expansion, and starting with Yodl version 4.00.00: not using `SUBST` definitions. See also `verborg`, which does not provide the protection against `SUBST` definitions.

While converting Yodl-documents to target document types Yodl frequently uses the (not further documented) builtin function `XXSUBST`. In the unlikely event that the text `XXSUBST(...)` must be written in a document, the sequence

        XXSUBST+CHAR(40)...CHAR(41)

can be used.

The text that is passed as argument to the `verb`-macro appears literally on the output, usually in a teletype font (that depends on the output format). This macro is for larger chunks, e.g., listings.

When starting the `verb(` macro on a line by itself and writing the closing parenthesis on a line by itself then those newlines also appear in the resulting verbatim text. To omit those lines immediately start the first line of text after `verb` and append the closing parenthesis to the last line of verbatim text. E.g.,

    verb(    First line of indented literal text
        Last line of indented literal text)

When unbalanced parameter lists are required, use `CHAR(40)` to get `(` and `CHAR(41)` to get `)`.

### 4.2.198: verbinclude(filename)

Reads filename and inserts it literally in the text, set in verbatim mode. not subject to macro expansion. The text appears literally on the output, usually in a teletype font (that depends on the output format). This macro is an alternative to `verb(...)`, when the text to set in verbatim mode is better kept in a separate file.

### 4.2.199: verbinsert(args)

Passes `args` to yodlverbinsert(1), inserting its output into the converted file. This macro can be used to insert, e.g., a line-numbered indented file, or a labeled subsection of a file, into the file that's currently being written by `yodl`. E.g,

    verbinsert(-ans4 file)       -- inserts file, showing line
                                    numbers, using a 4 blank-space
                                    character wide indentation.

    verbinsert(-ns4 //SECT file) -- inserts the section of file,
                                    labeled //SECT file, showing
                                    line numbers, using a 4
                                    blank-space character wide
                                    indentation.

### 4.2.200: verborg(text)

Sets `text` in verbatim mode: not subject to macro expansion or character table expansion, and starting with Yodl version 4.00.00: this macro replaces the previously defined `verb` macro. The current `verb` macro surrounds this macro by `PUSHSUBST` and `POPSUBST`.

The text that is passed as argument to the `verborg`-macro appears literally on the output, albeit that `SUBST` definitions are processed, usually in a teletype font (that depends on the output format). This macro is for larger chunks, e.g., listings.

When unbalanced parameter lists are required, use `CHAR(40)` to get `(` and `CHAR(41)` to get `)`.

### 4.2.201: verbpipe(command)(text)

Pipe text through command, but don't expand the output.

### 4.2.202: vindex()

Generate an index entry for LaTex() or texinfo v-indices. Its argument is the index entry. See also the `[cfkpt]index` macro.

### 4.2.203: whenhtml(text)

Sends `text` to the output when in HTML conversion mode. The text is further expanded if necessary.

### 4.2.204: whenlatex(text)

Sends `text` to the output when in LATEX conversion mode. The text is further expanded if necessary.

### 4.2.205: whenman(text)

Sends `text` to the output when in MAN conversion mode. The text is further expanded if necessary.

### 4.2.206: whenms(text)

Sends `text` to the output when in MS conversion mode. The text is further expanded if necessary.

### 4.2.207: whensgml(text)

Sends `text` to the output when in SGML conversion mode. The text is further expanded if necessary.

### 4.2.208: whentely(text)

Sends `text` to the output when in TELY conversion mode. The text is further expanded if necessary.

### 4.2.209: whentexinfo(text)

Sends `text` to the output when in TEXINFO conversion mode. The text is further expanded if necessary.

### 4.2.210: whentxt(text)

Sends `text` to the output when in TXT conversion mode. The text is further expanded if necessary.

### 4.2.211: whenxml(text)

Sends `text` to the output when in XML conversion mode. The text is further expanded if necessary.

### 4.2.212: xit(itemname)

Starts an xml menu item where the file to which the menu refers to is the argument of the xit() macro. It should be used as argument to xmlmenu(), which has a 3rd argument: the default path prefixed to the xit() elements.

This macro is only available within the xml-conversion mode. The argument must be a full filename, including .xml extension, if applicable.

No .xml extension indicates a subdirectory, containing another sub-menu.

### 4.2.213: xmlcommand(cmd)

Writes `cmd` to the output when converting to xml. The `cmd` is not further expanded by Yodl.

### 4.2.214: xmlmenu(order)(title)(menulist)

Starts an xmlmenu. Use itemization() to define the items. Only available in xml conversion. The menutitle appears in the menu as the heading of the menu. The menulist is a series of xit() elements, containing the name of the file to which the menu refers as their argument (including a final /). Prefixed to evert every xit()-element is the value of XXdocumentbase.

Order is the the `order' of the menu. If omitted, no order is defined.

### 4.2.215: xmlnewfile()

In XML output, starts a new file. All other formats are not affected. Note that you must take your own provisions to access the new file; say via links. Also, it's safe to start a new file just befoore opening a new section, since sections are accessible from the clickable table of contents. The XML converter normally only starts new files prior to a `chapter` definition.

### 4.2.216: xmlsetdocumentbase(name)

Defines `name` as the XML document base. No default. Only interpreted with xml conversions. It is used with the figure and xmlmenu macros.

### 4.2.217: xmltag(tag)(onoff)

Similar to `htmltag`, but used in the XML converter.

## 4.3: Conversion-related topics

### 4.3.1: Conversion-type specific literal commands

According to the format of the output file, the macro package defines a given symbol:

- `latex` when the output format is LaTeX,
- `html` when the output format is HTML,
- `man` when the output format is groff in conjunction with the man macro package,
- `ms` when the output format is groff with the ms package,
- `sgml` when the output format is SGML,
- `txt` when the output format is plain ASCII.
- `xml` when the output format is XML.

The defined symbol can be tested in a document to determine the conversion type.

Furthermore, the package defines the following macros to send literal text (commands in the output format) to the output file:

- `latexcommand(cmd)`: sends the LaTeX command `cmd` when in LaTeX conversion mode. The `cmd` is not further expanded.
- `htmlcommand(cmd)`: sends the HTML command `cmd` when in HTML conversion mode. The `cmd` is not further expanded.
- `htmltag(tag)(onoff)`: sends `<tag>` to the output when `onoff` is nonzero, or sends `</tag>` when `onoff` is zero. Only active in HTML conversions.
- `mancommand(cmd)`: sends `cmd` to the output when in man conversion mode. The `cmd` is not further expanded.
- `mscommand(cmd)`: sends `cmd` to the output when in ms conversion mode. The `cmd` is not further expanded.
- `roffcmd(dotcmd)(trailer)(secondline)(thirdline)`: sends a command to the output when in `man` or `ms` conversion mode. The `dotcmd` is the typical `groff` command that starts with a dot. All other arguments may be empty, but when given are interpreted as follows. The `trailer` follows the `dotcmd` on the same line. The `secondline` is sent on a separate line following the `dotcmd` and `trailer`. The `thirdline` is sent after that. Of the four arguments, `dotcmd` and `thirdline` are not subject to further expansion. All other arguments are further expanded if necessary.

  The `roffcmd` macro illustrates the complexity of dot-commands for the divers `groff` macro packages. E.g., a section title for the `man` package should look as

          .SH "Section Title"

  while the same command for the `ms` macro package must be sent as

          .SH
          Section Title
          .PP

  The `roffcmd` macro can be used to send these commands to the output file as follows:

          COMMENT(For the man output format:)
          roffcmd(.SH)("Section Title")()()

          COMMENT(For the ms output format:)
          roffcmd(.SH)()(Section Title)(.PP)()

- `sgmlcommand(cmd)`: sends the SGML command `cmd` when in SGML conversion mode. The `cmd` is not further expanded.
- `sgmltag(tag)(onoff)`: sends `<tag>` when `onoff` is nonzero, or sends `</tag>` when `onoff` is zero. Only active in SGML conversions.
- `txtcommand(cmd)`: implemented for compatibility reasons, though a `command' in plain ASCII output doesn't make much sense. The usefulness of this macro is rather in the fact that it only produces output when in ASCII conversion mode.

The above commands can be used to quickly implement a macro. E.g., the macro package implements the `it` macro (which starts an item in a list) as:

        DEFINEMACRO(it)(0)(
            latexcommand(\item )
            htmlcommand(<li> )
            ....
        )

Depending on the output format, `it()` applies one of the above expansions.

The above described format`command()` macros are implemented to send not further expanded strings (i.e., commands) to the output. The macro package also implements `when`format`()` macros to send any text, which is then subject to further expansion. These `when...()` macros are:

- `whenlatex(text)`: sends `text` when in LaTeX conversion mode,
- `whenhtml(text)`: sends `text` when in HTML conversion mode,
- `whenman(text)`: sends `text` when in man conversion mode,
- `whenms(text)`: sends `text` when in ms conversion mode,
- `whentxt(text)`: sends `text` when in ASCII conversion mode,
- `whensgml(text)`: sends `text` when in SGML conversion mode.

Once again, note that the difference between the `when`format`()` macros and the format`command()` macros is, that the former expands their argument while the latter does not. As an example, consider the following code fragment:

        You are now reading
            whenlatex(a LaTeX-generated
                      footnote(LaTeX is a great
                       document language!)
                      document)
            whenhtml(a HTML document via your
                     favorite browser)

The `when`format`()` macros are used here to make sure that the arguments to the macros are further expanded; this makes sure that the `footnote` macro in the `whenlatex` block gets treated as a footnote.

### 4.3.2: Figures

Figures in format-independent documents are a problem. You cannot avoid contact with the final format (HTML, LaTeX or whatever) if you want to include figures in a text.

Yodl approaches figures as follows:

- Figures can only be included in LaTeX, HTML and XML documents.
- For LaTeX, you must prepare a picture in an external file that is included in the document as en encapsulated PostScript file. Incidentally, that means that `epsf` must be stated as one of the LaTeX styles using the `latexoptions` macro. The default, however, can be modified using the `setlatexfigureext()` macro.
  The file in question is stated in Yodl without an extension. Yodl provides a default extension, `.ps`.
- For HTML and XML, you must prepare a picture in an external file that is placed in the document using the `<img src=...>` tag. The file must have the default extension (`.jpg`) or the extension specified with the `sethtmlfigureext()` macro.
- All other output formats do not include pictures in the document, but typeset something like insert figure .. here.

The macro to include a figure is called, appropriately, `figure`. It takes three arguments:

- The first argument is the filename. This name may include directories, but may not include the filename extension. The reason for this is, that Yodl supplies the correct extension once the output format is known.
- The second argument is the figure title, or the caption. Yodl prefixes this caption with the text Figure xx:, where xx is a number.
- The last argument is a label, which Yodl defines as a placeholder for the figure number.

For example, you might draw a picture or scan a photo and put it in a `.jpg` file, for usage with HTML documents. The conversion to PostScript could be automated, e.g., using a Yodl macro:

        SYSTEM(xpmtoppm picture.xpm | pnmtops > picture.ps)

See section 3.1.64 for details about using the `SYSTEM` macro.

After this, you would be reasonably safe that the picture is available for both HTML and LaTeX output. The picture would be typeset in a figure using:

        figure(picture)
        (A photo of me.)
        (photo)

Note how the first argument, the filename, does not contain an extension. The third argument, which is a label, can be used in, e.g.,

        See figure ref(photo) for a photograph showing me.

Yodl has a several auxiliary macros, which are:

- `fig(label)`: This macro is a shorthand for `getfigurestring() ref(label)`. It just makes typing shorter, and is used as e.g.: `See fig(photo) for a photograph.` Note that the string `figure` that is generated by this macro can be (re)defined, see below.
- `setfigurestring(name)`: This macro is similar to `setchapterstring` etc.. It defines the string that is used to identify a figure, and is (appropriately) `figure` by default. The macro `getfigurestring()` expands to the string in question. See also section 4.3.5.1 for a discussion of national language support.
- `sethtmlfigureext(.new)`: This macro redefines the filename extension for HTML conversions from `.gif` to `.new`. Note that you must include a leading dot in the redefinition.
  The new extension is used in the first following `figure` statement.
- `sethtmlfigurealign(align)`: This redefines the alignment of figures in HTML, which is default `bottom`. Check your HTML handbook for possible options; `top` and `center` should be fairly standard.
- `setlatexfigureext(.new)`: Redefines the extension from `.ps` to `.new`.

### 4.3.3: Fonts and sizes

Yodl's standard macro package supports the following macros to change fonts:

- `bf(text)`: sets `text` in boldface.
- `em(text)`: sets `text` emphasized, usually in italics.
- `tt(text)`: sets `text` in teletype.

Furthermore, the `tt()` macro does not expand macros occurring inside its argument. That means that you can safely write:

        In Yodl, you can use tt(includefile(somefile)) to include a file
        in your document.

The `tt()` macro should not be used for long listings of verbatim text; use `verb()` to set code samples etc..

Yodl's standard macro package has no commands to change font sizes, as the size is changed internally when appropriate (e.g., in section titles), nor is there a default macro to define other font-families.

### 4.3.4: Labels, links, references and URLs

References such as see ... for more information are very common in documents. Yodl supports three mechanisms to accomplish such references:

Labels and references:
Labels can be defined in a document as a placeholder for the last number used in a sectioning command. At other points in the document, references to those labels are used. The reference expands to the number, as in see section 1.3.

This mechanism is available in all output formats. Furthermore, the numeric reference (1.3 in the example of the previous paragraph) is in HTML a clickable reference that leads to the mentioned section.

Labels and links:
This mechanism can be used to set links in a document without using the number of a sectioning command, as in see the introduction for more information, with the introduction being a clickable link to some label.

This mechanism of course only leads to a clickable link in HTML: in other formats the text see the etc. is just typeset as is.

URLs:
Universal Resource Locators (URLs) are used to create links to other HTML documents or services, like HTML's `<a href=..>` method. The URLs of course only result in clickable links in HTML output; in other output formats only some descriptive text appears.

The above mechanism is implemented by the following macros:

- The macro `label(name)` defines a label named `name`. The name of the label can be used in a `ref` or `link` macro.
- The macro `ref(name)` sets a reference to the label named `name`. The text of the reference is the number of the last sectioning command that was active during the creation of the label. When using references it is therefore important to define the corresponding labels right after a sectioning command, as in

          section(How to install my program) label(howtoinstall)
          This section describes...
          ...
          See section ref(howtoinstall) for installation instructions.

  The macro `ref(howtoinstall)` expands to the number of the section named How to install my program.
- The macro `link(description)(name)` always expands to the `description`. In HTML output, a clickable link is created pointing to a label called `name`. For example:

          label(megahard)
          COMMENT(sigh...)
          The Jodel package isn't shareware, it isn't
          beggarware, it isn't freeware, it's
          bf(megahard-ware).
          ...
          Who wants a link(picosoft)(megahard)?

  This code fragment would always set the text picosoft, but under HTML a clickable link would appear pointing to `link(the text)(megahard)`.
- The macro `url(description)(location)` always expands to the `description`, but creates a hyperlink pointing to `location` in HTML. For example,

          Take a look at my
          url(homepage)(http://www.somewhere.nl/karel/karel.html).

  The text homepage always appears, but only in HTML it is a link. (Note that the double quotes, which are necessary in HTML around the location, are not required by Yodl.) To use a different font in the `description` part, surrond it inside the url parameter list, as in:

          The Yodl package can be obtained at the site tt(ftp.rug.nl) in the
          directory url(tt(/contrib/frank/software/yodl))
                       (ftp://ftp.rug.nl/contrib/frank/software/yodl).

- The macro `email(address)` is a special case of `url`: under HTML, the `address` appears as a clickable link in slanted font to mail `address`. For example:

          I can be reached at
          email(f.b.brokken@rug.nl).

  I can be reached at f.b.brokken@rug.nl.

  Always keep in mind that the name of a label must be exactly identical in both the `label` macro and in the `ref` or `link` macro. Other than that, the name is irrelevant.

  Furthermore, note that `lincludefile` is yet another macro defining a label: it includes a file and automatically creates a label just before the included file's text. That means that a Yodl file like:

          chapter(Introduction)
          sect(Welcome)
          lincludefile(WELCOME)(welcome)

          chapter(Technical information)
          lincludefile(TECHINFO)(techinfo)

  creates two labels: `WELCOME` and `TECHINFO`.

Here are some final thoughts about using labels and references:

- Don't put `weird' characters in label names. Generally, don't use spaces and tabs.
- The name of the label is always only an internal symbol; it does not appear in the output. Therefore, constructions such as the following are not correct:

          ref(em(labelname))

  The reason for the incorrectness is, what internal name should `em(labelname)` generate? Here probably an attempt is made to set a reference in italics. The right construction is of course to set whatever `ref()` returns in italics, as in:

          em(ref(labelname))

- The `label` macro should not appear nested inside another macro. There is no strict reason for this as far as Yodl is concerned; however, the processors of Yodl's output might go haywire. E.g., beware of the construction

          section(Introduction label(intro))

  The right form being

          section(Introduction)label(intro)

  (linking to `intro` usually does not show `Introduction`), or:

          label(intro)section(Introduction)

  (linking to `intro` usually does show `Introduction`).

### 4.3.5: Lists and environments

Yodl's default macros support the following lists and environments:

By default, the following lists are available:

Description lists:
A description list consists of a list of elements, where each element starts with a short (usually bold faced) description. The description list is generated by the `description()` macro. The elements of the list start with `dit()`. The `dit()` macro expects a short description of the item.

Example:

        A description list:
        description(
        dit(First this:) One item.
        dit(Then this:) Another item.
        )

Enumeraton lists:
An enumeration list consist of sequentially numbered elements. The list is generated by the `enumeration()` macro. Its elements start with the `eit()` macro.

Example:

        An enumerated list:
        enumeration(
        eit() One item.
        eit() Another item.
        )

Itemized lists:
An itemized lists consists of indented items, usually preceded by a bullet.

An itemized list is produced by the `itemization()` macro, which has one argument: the items themselves. These items must start with `it()`.

Example:

        An itemized list:
        itemization(
        it() One item.
        it() Another item.
        )

Specialized environments are:

Centered text:
Centering text may not be available in all output formats. When unavailable, the text is typeset left-flushed.

Centered text is generated by the `center()` macro. Line brakes within centered text may be obtained using the `nl()` macro.

Example:

        center(
        Centered text. nl()
        Another line of centered text.
        )

Verbatim text:
Verbatim text appears on the output exactly in the same layout as it is in the input file. Typesetting text in verbatim mode is useful for, e.g., source files. Depending on the output format, the font of the verbatim text is changed to a teletype font.

The text must either be inside the `verb()` macro. For example:

        verb(
            This is totally verbatim text.
            It is not further processed by Yodl.
        )

The verbatim text is of course not subject to macro expansion by Yodl. Note, however, that `SUBST` transformations will take place, as these substitutions take place during the lexical scanning phase of `Yodl`'s input, and are not part of the macro-expansion process. See also section 3.1.62.

Furthermore, if a character translation table has been defined, the argument of the `verb()` macro will also be subject to character table transformations. By temporarily suppressing the active character table (see section PUSHCHARTABLE 3.1.53) this can be prevented.

Quotations:
Quotations are usually indented with respect to their surrounding text. It is for the author to decided whether the quoted text should be typeset normally, or that it should be bold-faced or emphasized. To insert a quotation use the `quote()` macro:

        Shakespeare once wrote:
        quote(
            ``To be or not to be, that's the question''
        )

#### 4.3.5.1: National language support

Yodl includes rudimentary national language support (NLS), in the sense that it allows you to redefine the strings identifying chapters or parts, or the strings identifying figures. E.g., a command `chapter(Introduction)` by default results in the text Chapter 1: Introduction.

Using the `setchapterstring(text)` macro, the Chapter text can be redefined. E.g., in a Dutch text you might put

        setchapterstring(Hoofdstuk)

somewhere near the beginning of your document. Similar to `setchapterstring`, a macro `getchapterstring` exists returning the text identifying chapters. (Internally, `getchapterstring` is of course used to actually set the text). To redefine the text to identify a part, use `setpartstring(text)`; to redefine the text to identify a figure, use `setfigurestring(text)`.

The `set....string` macros only influence how Yodl names chapters or parts in HTML, `man`, `ms` or `txt` output. LaTeX output is not affected, since LaTeX does its own NLS. Usually, NLS is present for LaTeX as a `style file' named, e.g., `dutch.sty`. Therefore, if you want a Dutch document, you need to:

- put `latexpackage(dutch)(babel)`in the preamble of the document. This ensures that LaTeX uses Dutch abbreviation rules.
- redefine the chapter and part names for non-LaTeX output, using:

          setlanguage(dutch)

- Finally, you should probably type your text in Dutch.

The `setlanguage()` macro expects one argument: the name of the language that is used. See section 4.2 for details about this macro. The `setlanguage()` macro redefines the language-dependent section (and other) headers, and depends on the availability of the corresponding `language<name>()` macro, where `<name>` is the name of the language (by convention `<name>` states the english name of the language). Currently, `languagedutch()`, `languageenglish()` (the default), and `languageportugese()` are available. It's easy to expand this little set with macros for other languages. The `setlanguage()` macro merely requires the specification of the language. For example:

        setlanguage(english)

This macro installs the following defaults (corresponding translations should be defined for other languages):

        settocstring(Table of Contents)
        setaffilstring(Affiliation)
        setauthorstring(Author)
        setchapterstring(Chapter)
        setdatestring(Date)
        setfigurestring(Figure)
        setpartstring(Part)
        settitlestring(Title)

#### 4.3.5.2: Pagebreaks after the title and table of contents

Yodl inserts page-breaks in a limited number of cases:

- A pagebreak is generated after the title information in `book` and `report` documents.
- A pagebreak is generated after a table of contents in all documents.

So, when a document has both title information and a table of contents then whatever follows next normally starts on a separate page. Furthermore, if the document is a `book` or a `report`, the title and table of contents will also be separated by pagebreaks.

This behavior can be modified using the `(no)titleclearpage()` and `(no)tocclearpage()` directives, further described in section 4.3.7.

### 4.3.6: Sectioning

This section describes the sectioning commands for `article`s, `report`s, `book`s and for `plainhtml`. The document type `manpage` defines its own sectioning commands (cf. section 4.1.2:

- `part(title)`: Starts a new part. Only available in `book` documents.
- `chapter(title)`: Starts a new chapter. Only available in `book` or `report` documents.
- `sect(title)`: Starts a section.
- `subsect(title)`: A subsection.
- `subsubsect(title)`: A sub-subsection.
- `subsubsubsect(title)`: An even smaller sectioning command.

These macros generate entries in the table of contents and use numbering, which means that each section is prefixed with a number (1, 1.1, 1.2, and so on). The macros are also available with an `n` prefix (`npart`, `nchapter`, `nsect` etc.) which generate neither entries in the table of contents nor numbers. The `n`-versions can be used in, e.g., an article where the sectioning commands should show their captions, but not any numbers generated by default.

Sectioning should always start at the top level sections of the available document: `chapter` for reports, `sect` for articles, etc.. If you start a document with a lower sectioning command (e.g., when you start an article with a `subsect`), the numbering of sections may go haywire. The only exception to this rule is the `part` of a `book` document: parts are optional, in books, `chapter`s may be the top sectioning commands. Summarizing, books or reports should start with `chapter`. Articles should start with `sections`.

The sectioning commands have a further function: when `label` statements appear after the sectioning command, then a label name is used as a placeholder for the last generated number. This is further described in section 4.3.4.

### 4.3.7: Typesetting modifiers

This section lists various macros that can be used to modify the looks of your document. When used, these macros must appear before stating the document type with `article`, `report`, `book`, `manpage` or `plainhtml`.

- `abstract(text)`: This macro is relevant for all output formats. The `text` is added to the document after the title, author and date information, but before the table of contents. The abstract is usually set as a quote, in italics font (though this depends on the output format). Abstracts are supported in `article`s and `report`s, but not in other document types. I.e., if you need introductory text in a `book`, you should start with a non-numbered chapter that holds this text.
- `affiliation(site)`: This macro is relevant for `article`, `report` and `book` documents. It defines the affiliation of the author. The `site` information appears in the title, below the author's name.
- `htmlbodyopt(option)(value)`: This macro adds `option="value"` to the `<body>` tag that is generated for HTML output. The HTML converter generates `<body>` tags each time that a new file is started; i.e., at the top of the document and at each chapter-file. Different HTML browsers support different `<body>` tag options, but useful ones may be e.g.:

          htmlbodyopt(fgcolor)(#000000)
          htmlbodyopt(bgcolor)(#FFFFFF)

  This defines the foreground color as pure white (red/green/blue all 0) and the background color as black (red/green/blue all hexadecimal FF, or 255). Another useful option may be `htmlbodyopt(background) (some.gif)`, defining `some.gif` as the page background.

  See the documentation on HTML for more information.

  Note that `value` is automatically surrounded by double quotes when this macro is used. They should not be used by authors using this macro.

- `latexdocumentclass(class)`: This macro forces the `\documentclass{...}` setting in LaTeX output to `class`.
- `latexlayoutcmds(commands)`: This macro can be used to specify your own LaTeX layout commands. When present, the `commands` are placed in LaTeX output following the `\documentclass` definition.
- `latexoptions(options)`: This macro is only relevant for LaTeX output formats, it is not expanded in other formats. The `options` are used in LaTeX's `\documentclass` definition; e.g., a useful option might be `dina4`. Multiple options should be separate by commas, according to the LaTeX convention.
- `latexpackage(options)(name)`: This macro is only relevant for LaTeX output formats, it is not expanded in other formats. Each package should have its own `latexpackage()` statement. If there are no options, the `options` argument should remain empty. Here is an example using this macro:

          latexpackage(dutch)(babel)

- `mailto(email)`: The `mailto` macro is only expanded in HTML documents, it is ignored in other formats. It defines where mail about the document should be sent to.
- `nosloppyhfuzz()`: By default, the LaTeX output contains the text

          \hfuzz=4pt

  which is placed there by the macro package. This suppresses overfull hbox warnings of LaTeX when the overfull-ness is less than 4pt. Use `nosloppyhfuzz()` to get the standard LaTeX warnings about overfull hboxes.
- `notableofcontents()`: As the name suggests, this macro suppresses the generation of the table of contents. For HTML that means that no clickable index of sections appears after the document title.

  The table of contents is by default suppressed in `plainhtml` and `manpage` documents.

- `notitleclearpage()`: Normally, Yodl inserts a `clearpage()` directive after typesetting title information in `book` or `report` documents, but not in `article` documents. Use `notitleclearpage` to suppress this directive.
- `notocclearpage()` (no table-of-contents clear-page): In all document types, Yodl inserts a `clearpage()` directive following the table of contents. Use `notocclearpage()` to suppress that.
- `noxlatin()`: The LaTeX output contains by default the command to include the file `xlatin1.tex`, distributed with Yodl. This file maps Latin-1 characters to LaTeX-understandable codes and makes sure that you can type characters such as `ü`, and still make them processable by LaTeX. If you don't want this, put `noxlatin()` in the preamble.
- `standardlayout()`: This is another LaTeX option. Use `standardlayout()` to get `vanilla' LaTeX layout, possibly indenting paragraphs and using fairly limited vertical spacing between paragraphs. This macro is ignored for other conversion types.
- `titleclearpage()`: Forces the insertion of a `clearpage()` directive after the title information has been typeset. This behavior is the default in `book` and `report` documents. See also `notitleclearpage()`.
- `tocclearpage()`: Forces the insertion of a `clearpage()` directive following the table of contents. This behavior is default in all document types; the macro is provided for consistency reasons with `(no)titleclearpage()`.

Note again: these modifiers must appear before the document type definition.

### 4.3.8: Miscellaneous commands

The following is a list of commands that don't fall in one of the above categories.

- `clearpage()`: This macro starts a new page in LaTeX. For HTML, a horizontal rule is shown. (Note that the macro package sometimes inserts new pages by itself; e.g., following a table of contents. See also section 4.3.7 for a discussion of `(no)titleclearpage()` and `(no)tocclearpage()`.)
- `def(macro)(nrofarguments)(definition)`: This defines a new macro `macro` having `nrofarguments` arguments, and expanding to `definition`. The markers `ARG`x, where x is 1, 2, etc., can be used in the `definition` part to indicate where arguments should be pasted in. This macro is a shorthand for `DEFINEMACRO`, see section 3.1.11.
- `footnote(text)`: This macro sets `text` as a footnote when the output format allows it. When not, the text is set in parentheses.
- `gagmacrowarning(name name ...)`: This macro suppresses `yodl`'s warnings cannot expand possible user macro name, where `name` is a candidate macro name. `gagmacrowarning` is a synonym for `NOUSERMACRO`, described in section 3.1.41.
  E.g., if your document contains `"as for manpages, see sed(1), tr(1) and awk(1)"`, and if you get tired of warnings about possible user macros sed, tr and awk, try the following:

          gagmacrowarning(sed tr awk)
          ...
          As for manpages, see sed(1), tr(1) and awk(1).

- `htmlnewfile()`: Starts a new subfile in HTML output. This stanza is also automatically generated when the HTML converter encounters a `chapter` directive. Using `htmlnewfile`, the output can be split at any point. However make sure that the subfile is still reachable; e.g., by creating a clickable link with `label` and `ref`, or `label` and `link`.
- `includefile(file)`: Includes `file` and defines a label (see the `label` macro) with the same name. Furthermore, a message about the inclusion is shown on the screen. The `file` is searched for relative to the directory of the file in which the `includefile` macro was used (or relative to the directory where the `yodl` run was started when the `--legacy-include` or `-L` option was provided) and also in the system-wide include directory. The default extension `.yo` is supplied if necessary.
  The `lincludefile` macro is handy in the following situation:

          chapter(Introduction)
          lincludefile(INTRO)(intro)

  This fragment starts a chapter and includes a file. Here the label name (`INTRO`) can also be used to refer to the chapter as the `lincludefile` stanza appears immediately following the corresponding sectioning command.
- `nl()`: Forces a new line. Some output formats may produce an error upon the usage of `nl()` in `unexpected' places; e.g., LaTeX won't allow new lines in the footnote text (as defined in the `footnote` macro). Using `nl()` in running text should however be ok. Example:

          This line is nl()
          broken in two.

- `redefinemacro(macro)(nrofargs)(redef)`: This command (re)defines a macro, expecting `nrofargs` arguments, to `redef`. If a previous definition of the macro existed, it is overruled. Example:

          redefinemacro(clearpage)(0)(\
          em(---New page starts here---))

  Use `ARG`x in the `redef` part to indicate where all arguments should occur, as in the following imaginary macro to typeset a literature reference:

          redefinemacro(litref)(3)(
              Title: bf(ARG1) nl()
              Author(s): em(ARG2) nl()
              Published by: ARG3
          )
          ...
          litref(Java in a Nutshell)
            (David Flanagan)
            (O'Reilly & Associates, Inc.)

  The `redefinemacro` statement also has a shorthand called `redef`.

## 4.4: Locations of the macros

The files defining the macros are by default installed to the directory `/usr/local/share/yodl` during Yodl's installation process (Note that this diverts from an earlier default: `/usr/local/lib/yodl`; furthermore, some systems or some distributions may use other locations).

The files in this directory are organized as follows:

- The files that should be read for a particular conversion are named after their conversion, e.g., `latex.yo` and `html.yo`. These files must be processed by Yodl before your document can be converted accordingly. The provided `yodl2...` scripts take care of that automatically.
- All support counters, symbols and macros are defined in files named `std.<conversion>.yo`, e.g., `std.html.yo, std.latex.yo`. These files may be modified without notice, and are an essential part of the Yodl macros. They should not be modified by hand, as they are created by the macro generating process.
- The predefined character tables are found in files names `chartables/<conversion>.yo`.

The (binary) Yodl package contains the following programs and support files:

- The `yodl` program itself, which generates converted document(s);
- The `yodlpost` postprocessor, which performs fixups for conversion formats. Using `yodlpost` is required for formats whose documents cannot be created in one pass by `yodl` itself;
- Auxiliary scripts such as `yodl2tex`, `yodl2html`;
- The macros and character tables for the various conversion types;
- The raw macros and the macro-generating scripts;
- The documentation (html and manual pages)

The source Yodl package contains all the sources files, installation guides, change-logs etc., that are required to compile the binary programs. Those who want to compile Yodl themselves, must have a `C` compiler (preferably the `Gnu` C compiler) available, and preferably the `icmake` program maintenance utility. Basic support for `make` is provided as well.

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