Perl::Critic::Utils(3pm)

NAME
Perl::Critic::Utils - General utility subroutines and constants for Perl::Critic and derivative distributions.

DESCRIPTION
This module provides several static subs and variables that are useful for developing Perl::Critic::Policy subclasses. Unless you are writing Policy modules, you probably don't care about this package.

INTERFACE SUPPORT
This is considered to be a public module. Any changes to its interface will go through a deprecation cycle.

IMPORTABLE SUBS

"find_keywords( $doc, $keyword )"
    DEPRECATED: Since version 0.11, every Policy is evaluated at each element of the document. So you shouldn't need to go looking for a particular keyword. If you do want to use this, please import it via the ":deprecated" tag, rather than directly, to mark the module as needing updating.

    Given a PPI::Document as $doc, returns a reference to an array containing all the PPI::Token::Word elements that match $keyword. This can be used to find any built-in function, method call, bareword, or reserved keyword. It will not match variables, subroutine names, literal strings, numbers, or symbols. If the document doesn't contain any matches, returns undef.

is_assignment_operator( $element )
    Given a PPI::Token::Operator or a string, returns true if that token represents one of the assignment operators (e.g. "= &&= ||= //= += -=" etc.).

is_perl_global( $element )
    Given a PPI::Token::Symbol or a string, returns true if that token represents one of the global variables provided by the English module, or one of the builtin global variables like %SIG, %ENV, or @ARGV. The sigil on the symbol is ignored, so things like $ARGV or $ENV will still return true.

is_perl_builtin( $element )
    Given a PPI::Token::Word, PPI::Statement::Sub, or string, returns true if that token represents a call to any of the builtin functions.

is_perl_bareword( $element )
    Given a PPI::Token::Word, PPI::Statement::Sub, or string, returns true if that token represents a bareword (e.g. "if", "else", "sub", "package").

is_perl_filehandle( $element )
    Given a PPI::Token::Word, or string, returns true if that token represents one of the global filehandles (e.g. "STDIN", "STDERR", "STDOUT", "ARGV"). Note that this function will return false if given a filehandle that is represented as a typeglob (e.g. *STDIN)

is_perl_builtin_with_list_context( $element )
    Given a PPI::Token::Word, PPI::Statement::Sub, or string, returns true if that token represents a call to any of the builtin functions that provide a list context to the following tokens.

is_perl_builtin_with_multiple_arguments( $element )
    Given a PPI::Token::Word, PPI::Statement::Sub, or string, returns true if that token represents a call to any of the builtin functions that can take multiple arguments.

is_perl_builtin_with_no_arguments( $element )
    Given a PPI::Token::Word, PPI::Statement::Sub, or string, returns true if that token represents a call to any of the builtin functions that cannot take any arguments.

is_perl_builtin_with_one_argument( $element )
    Given a PPI::Token::Word, PPI::Statement::Sub, or string, returns true if that token represents a call to any of the builtin functions that takes one and only one argument.

is_perl_builtin_with_optional_argument( $element )
    Given a PPI::Token::Word, PPI::Statement::Sub, or string, returns true if that token represents a call to any of the builtin functions that takes no more than one argument.

    The sets of values for which is_perl_builtin_with_multiple_arguments(), is_perl_builtin_with_no_arguments(), is_perl_builtin_with_one_argument(), and is_perl_builtin_with_optional_argument() return true are disjoint and their union is precisely the set of values that is_perl_builtin() will return true for.

is_perl_builtin_with_zero_and_or_one_arguments( $element )
    Given a PPI::Token::Word, PPI::Statement::Sub, or string, returns true if that token represents a call to any of the builtin functions that takes no and/or one argument.

    Returns true if any of is_perl_builtin_with_no_arguments(), is_perl_builtin_with_one_argument(), and is_perl_builtin_with_optional_argument() returns true.

is_qualified_name( $name )
    Given a string, PPI::Token::Word, or PPI::Token::Symbol, answers whether it has a module component, i.e. contains "::".

precedence_of( $element )
    Given a PPI::Token::Operator or a string, returns the precedence of the operator, where 1 is the highest precedence. Returns undef if the precedence can't be determined (which is usually because it is not an operator).

is_hash_key( $element )
    Given a PPI::Element, returns true if the element is a literal hash key. PPI doesn't distinguish between regular barewords (like keywords or subroutine calls) and barewords in hash subscripts (which are considered literal). So this subroutine is useful if your Policy is searching for PPI::Token::Word elements and you want to filter out the hash subscript variety. In both of the following examples, "foo" is considered a hash key:

        $hash1{foo} = 1;
        %hash2 = (foo => 1);

    But if the bareword is followed by an argument list, then perl treats it as a function call. So in these examples, "foo" is not considered a hash key:

        $hash1{ foo() } = 1;
        &hash2 = (foo() => 1);

is_included_module_name( $element )
    Given a PPI::Token::Word, returns true if the element is the name of a module that is being included via "use", "require", or "no".

is_integer( $value )
    Answers whether the parameter, as a string, looks like an integral value.

is_class_name( $element )
    Given a PPI::Token::Word, returns true if the element that immediately follows this element is the dereference operator "->". When a bareword has a "->" on the right side, it usually means that it is the name of the class (from which a method is being called).

is_label_pointer( $element )
    Given a PPI::Token::Word, returns true if the element is the label in a "next", "last", "redo", or "goto" statement. Note this is not the same thing as the label declaration.

is_method_call( $element )
    Given a PPI::Token::Word, returns true if the element that immediately precedes this element is the dereference operator "->". When a bareword has a "->" on the left side, it usually means that it is the name of a method (that is being called from a class).

is_package_declaration( $element )
    Given a PPI::Token::Word, returns true if the element is the name of a package that is being declared.

is_subroutine_name( $element )
    Given a PPI::Token::Word, returns true if the element is the name of a subroutine declaration. This is useful for distinguishing barewords and from function calls from subroutine declarations.

is_function_call( $element )
    Given a PPI::Token::Word returns true if the element appears to be call to a static function. Specifically, this function returns true if "is_hash_key", "is_method_call", "is_subroutine_name", "is_included_module_name", "is_package_declaration", "is_perl_bareword", "is_perl_filehandle", "is_label_pointer" and "is_subroutine_name" all return false for the given element.

first_arg( $element )
    Given a PPI::Element that is presumed to be a function call (which is usually a PPI::Token::Word), return the first argument. This is similar of parse_arg_list() and follows the same logic. Note that for the code:

        int($x + 0.5)

    this function will return just the $x, not the whole expression. This is different from the behavior of parse_arg_list(). Another caveat is:

        int(($x + $y) + 0.5)

    which returns "($x + $y)" as a PPI::Structure::List instance.

parse_arg_list( $element )
    Given a PPI::Element that is presumed to be a function call (which is usually a PPI::Token::Word), splits the argument expressions into arrays of tokens. Returns a list containing references to each of those arrays. This is useful because parentheses are optional when calling a function, and PPI parses them very differently. So this method is a poor-man's parse tree of PPI nodes. It's not bullet-proof because it doesn't respect precedence. In general, I don't like the way this function works, so don't count on it to be stable (or even present).

split_nodes_on_comma( @nodes )
    This has the same return type as parse_arg_list() but expects to be passed the nodes that represent the interior of a list, like:

        'foo', 1, 2, 'bar'

is_script( $document )
    This subroutine is deprecated and will be removed in a future release. You should use the "is_program()" in Perl::Critic::Document method instead.

is_in_void_context( $token )
    Given a PPI::Token, answer whether it appears to be in a void context.

policy_long_name( $policy_name )
    Given a policy class name in long or short form, return the long form.

policy_short_name( $policy_name )
    Given a policy class name in long or short form, return the short form.

all_perl_files( @directories )
    Given a list of directories, recursively searches through all the directories (depth first) and returns a list of paths for all the files that are Perl code files. Any administrative files for CVS or Subversion are skipped, as are things that look like temporary or backup files.

    A Perl code file is:

    •   Any file that ends in .PL, .pl, .pm, .psgi, or .t

    •   Any file that has a first line with a shebang containing 'perl'

severity_to_number( $severity )
    If $severity is given as an integer, this function returns $severity but normalized to lie between $SEVERITY_LOWEST and $SEVERITY_HIGHEST. If $severity is given as a string, this function returns the corresponding severity number. If the string doesn't have a corresponding number, this function will throw an exception.

is_valid_numeric_verbosity( $severity )
    Answers whether the argument has a translation to a Violation format.

verbosity_to_format( $verbosity_level )
    Given a verbosity level between 1 and 10, returns the corresponding predefined format string. These formats are suitable for passing to the "set_format" method in Perl::Critic::Violation. See the perlcritic documentation for a listing of the predefined formats.

hashify( @list )
    Given @list, return a hash where @list is in the keys and each value is 1. Duplicate values in @list are silently squished.

interpolate( $literal )
    Given a $literal string that may contain control characters (e.g.. '\t' '\n'), this function does a double interpolation on the string and returns it as if it had been declared in double quotes. For example:

        'foo \t bar \n' ...becomes... "foo \t bar \n"

shebang_line( $document )
    Given a PPI::Document, test if it starts with "#!". If so, return that line. Otherwise return undef.

words_from_string( $str )
    Given config string $str, return all the words from the string. This is safer than splitting on whitespace.

"is_unchecked_call( $element, $autodie_modules )"
    Given a PPI::Element, test to see if it contains a function call whose return value is not checked. The second argument is an array reference of module names which export "autodie". The "autodie" module is always included in this list by default.

IMPORTABLE VARIABLES

$COMMA
$FATCOMMA
$COLON
$SCOLON
$QUOTE
$DQUOTE
$BACKTICK
$PERIOD
$PIPE
$EMPTY
$EQUAL
$SPACE
$SLASH
$BSLASH
$LEFT_PAREN
$RIGHT_PAREN
    These character constants give clear names to commonly-used strings that can be hard to read when surrounded by quotes and other punctuation. Can be imported in one go via the ":characters" tag.

$SEVERITY_HIGHEST
$SEVERITY_HIGH
$SEVERITY_MEDIUM
$SEVERITY_LOW
$SEVERITY_LOWEST
    These numeric constants define the relative severity of violating each Perl::Critic::Policy. The "get_severity" and "default_severity" methods of every Policy subclass must return one of these values. Can be imported via the ":severities" tag.

$DEFAULT_VERBOSITY
    The default numeric verbosity.

$DEFAULT_VERBOSITY_WITH_FILE_NAME
    The numeric verbosity that corresponds to the format indicated by $DEFAULT_VERBOSITY, but with the file name prefixed to it.

$TRUE
$FALSE
    These are simple booleans. 1 and 0 respectively. Be mindful of using these with string equality. "$FALSE ne $EMPTY". Can be imported via the ":booleans" tag.

IMPORT TAGS
The following groups of functions and constants are available as parameters to a "use Perl::Critic::Util" statement.

":all"
    The lot.

":booleans"
    Includes: $TRUE, $FALSE

":severities"
    Includes: $SEVERITY_HIGHEST, $SEVERITY_HIGH, $SEVERITY_MEDIUM, $SEVERITY_LOW, $SEVERITY_LOWEST, @SEVERITY_NAMES

":characters"
    Includes: $COLON, $COMMA, $DQUOTE, $EMPTY, $FATCOMMA, $PERIOD, $PIPE, $QUOTE, $BACKTICK, $SCOLON, $SPACE, $SLASH, $BSLASH $LEFT_PAREN $RIGHT_PAREN

":classification"
    Includes: "is_assignment_operator", "is_class_name", "is_function_call", "is_hash_key", "is_included_module_name", "is_integer", "is_label_pointer", "is_method_call", "is_package_declaration", "is_perl_bareword", "is_perl_builtin", "is_perl_filehandle", "is_perl_global", "is_perl_builtin_with_list_context" "is_perl_builtin_with_multiple_arguments" "is_perl_builtin_with_no_arguments" "is_perl_builtin_with_one_argument" "is_perl_builtin_with_optional_argument" "is_perl_builtin_with_zero_and_or_one_arguments" "is_qualified_name", "is_script", "is_subroutine_name", "is_unchecked_call" "is_valid_numeric_verbosity"

    See also Perl::Critic::Utils::PPI.

":data_conversion"
    Generic manipulation, not having anything specific to do with Perl::Critic.

    Includes: "hashify", "words_from_string", "interpolate"

":ppi"
    Things for dealing with PPI, other than classification.

    Includes: "first_arg", "parse_arg_list"

    See also Perl::Critic::Utils::PPI.

":internal_lookup"
    Translations between internal representations.

    Includes: "severity_to_number", "verbosity_to_format"

":language"
    Information about Perl not programmatically available elsewhere.

    Includes: "precedence_of"

":deprecated"
    Not surprisingly, things that are deprecated. It is preferred to use this tag to get to these functions, rather than the function names themselves, so as to mark any module using them as needing cleanup.

    Includes: "find_keywords"

SEE ALSO
Perl::Critic::Utils::Constants, Perl::Critic::Utils::McCabe, Perl::Critic::Utils::PPI,

AUTHOR
Jeffrey Ryan Thalhammer <jeff@imaginative-software.com>

COPYRIGHT
Copyright (c) 2005-2023 Imaginative Software Systems

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of this license can be found in the LICENSE file included with this module.