1 Accessing Check Syntax Programmatically

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On this page:

show-content
make-traversal
current-annotations
current-max-to-send-at-once
syncheck-annotations<%>
syncheck: find-source-object
syncheck: add-background-color
syncheck: add-require-open-menu
syncheck: add-docs-menu
syncheck: add-id-set
syncheck: add-arrow
syncheck: add-arrow/ name-dup
syncheck: add-arrow/ name-dup/ pxpy
syncheck: add-tail-arrow
syncheck: add-mouse-over-status
syncheck: add-prefixed-require-reference
syncheck: add-jump-to-definition
syncheck: add-definition-target
syncheck: color-range
syncheck: add-rename-menu
annotations-mixin
syncheck: find-source-object
syncheck: add-background-color
syncheck: add-require-open-menu
syncheck: add-docs-menu
syncheck: add-rename-menu
syncheck: add-arrow
syncheck: add-arrow/ name-dup
syncheck: add-arrow/ name-dup/ pxpy
syncheck: add-tail-arrow
syncheck: add-mouse-over-status
syncheck: add-jump-to-definition
syncheck: add-id-set
syncheck: color-range
syncheck: add-prefixed-require-reference

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### 1`` Accessing Check Syntax Programmatically

(require drracket/check-syntax)
| package: drracket-tool-lib

> procedure (show-content file-or-stx) → (listof vector?)
> | file-or-stx |  | : |  |
> (or/c path-string?
> (and/c syntax?
> (λ (x) (path-string? (syntax-source x)))))

This procedure composes the other pieces of this library together in a way that can be used for REPL-style experimentation with the results from Check Syntax, as shown in the example below. The list it returns has one vector for each call that would be made to the object in current-annotations. Each vector’s first element is a symbol naming a method in syncheck-annotations<%> and the other elements of the vector are the arguments passed to the method.

This doesn’t work as well for use in a real tool, however, because it doesn’t account for the callback procedures present in syncheck:add-arrow/name-dup/pxpy and syncheck:add-id-set and the resulting vectors are probably less convenient to work with than direct method calls for most uses of this library. Nevertheless, it gives a quick feel for the results that can come back from Check Syntax.

See annotations-mixin for some example code to use the other parts of this library.

Note that the paths in the example below have been replaced via make-paths-be-module-paths in order to make the results be platform independent.

> > (define (make-paths-be-module-paths x)
> (let loop ([x x])
> (cond
> [(pair? x) (cons (loop (car x)) (loop (cdr x)))]
> [(vector? x) (for/vector ([x (in-vector x)])
> (loop x))]
> [(path? x) (path->relative-string/library x)]
> [else x])))
> > (let ([example-module
> '(module m racket (λ (x) x))])
> (make-paths-be-module-paths
> (show-content
> (read-syntax
> (build-path (current-directory) "dummy-file.rkt")
> (open-input-string (format "~s" example-module))))))
> '(#(syncheck:add-require-open-menu 10 16 "<collects>/racket/main.rkt")
> #(syncheck:add-tail-arrow 17 26)
> #(syncheck:add-background-color 1 7 "palegreen")
> #(syncheck:add-docs-menu
> 1
> 7
> module
> "View documentation for “module” from racket/base, racket"
> "<doc>/reference/module.html"
> (form ('#%kernel module))
> "(form._((quote._~23~25kernel)._module))")
> #(syncheck:add-arrow/name-dup/pxpy
> 23
> 24
> 0.5
> 0.5
> 26
> 27
> 0.5
> 0.5
> #t
> 0
> #f
> #<procedure:name-dup?>)
> #(syncheck:add-background-color 20 21 "palegreen")
> #(syncheck:add-docs-menu
> 20
> 21
> λ
> "View documentation for “λ” from racket/base, racket"
> "<doc>/reference/lambda.html"
> (form ((lib "racket/private/base.rkt") λ))
> "(form._((lib._racket/private/base..rkt)._~ce~bb))")
> #(syncheck:add-jump-to-definition
> 20
> 21
> new-λ
> "<collects>/racket/private/kw.rkt"
> ())
> #(syncheck:add-mouse-over-status 20 21 "imported from “racket”")
> #(syncheck:add-arrow/name-dup/pxpy
> 10
> 16
> 0.5
> 0.5
> 20
> 21
> 0.5
> 0.5
> #t
> 0
> module-lang
> #<procedure:name-dup?>)
> #(syncheck:add-background-color 20 21 "palegreen")
> #(syncheck:add-docs-menu
> 20
> 21
> λ
> "View documentation for “λ” from racket/base, racket"
> "<doc>/reference/lambda.html"
> (form ((lib "racket/private/base.rkt") λ))
> "(form._((lib._racket/private/base..rkt)._~ce~bb))")
> #(syncheck:add-jump-to-definition
> 20
> 21
> new-λ
> "<collects>/racket/private/kw.rkt"
> ())
> #(syncheck:add-mouse-over-status 20 21 "imported from “racket”")
> #(syncheck:add-arrow/name-dup/pxpy
> 10
> 16
> 0.5
> 0.5
> 20
> 21
> 0.5
> 0.5
> #t
> 0
> module-lang
> #<procedure:name-dup?>)
> #(syncheck:add-mouse-over-status 10 16 "1 bound occurrence")
> #(syncheck:add-mouse-over-status 23 24 "1 bound occurrence"))

> > procedure
> > (make-traversal namespace path) |  | → |  |
> > (->* (syntax?)
> > ((-> any/c void?))
> > void?)
> > (-> void?)
> namespace : namespace?
> path : (or/c #f path-string?)

This function creates some local state about a traversal of syntax objects and returns two functions. The first one should be called with each of the (fully expanded) syntax objects that make up a program (there will be only one if the program is a module) and then the second one should be called to indicate there are no more.

The optional argument to the first function is ignored. It is left there for historical reasons. In the past it was called for each sequence of binding identifiers encountered in define-values, define-syntaxes, and define-values-for-syntax.

During the dynamic extent of the call to the two result functions, the value of the current-annotations parameter is consulted and various methods are invoked in the corresponding object (if any), to indicate what has been found in the syntax object. These methods will only be called if the syntax objects have source locations.

> parameter (current-annotations)
> → (or/c #f (is-a?/c syncheck-annotations<%>))
> (current-annotations ca) → void?
> ca : (or/c #f (is-a?/c syncheck-annotations<%>))

The methods of the value of this parameter are invoked by the functions returned from make-traversal.

> parameter (current-max-to-send-at-once)
> → (or/c +inf.0 (and/c exact-integer? (>=/c 2)))
> (current-max-to-send-at-once m) → void?
> m : (or/c +inf.0 (and/c exact-integer? (>=/c 2)))

No longer used.

interface syncheck-annotations<%> : interface?

Classes implementing this interface are accceptors of information about a traversal of syntax objects. See make-traversal.
Do not implement this interface directly, as it is liable to change without warning. Instead, use the annotations-mixin and override the methods you’re interested in. The annotations-mixin will keep in sync with this interface, providing methods that ignore their arguments.

> > method (send a-syncheck-annotations syncheck:find-source-object stx)
> > → (or/c #f (not/c #f))
> > stx : syntax?

> This should return #f if the source of this syntax object is uninteresting for annotations (if, for example, the only interesting annotations are those in the original file and this is a syntax object introduced by a macro and thus has a source location from some other file).

> Otherwise, it should return some (non-#f) value that will then be passed to one of the other methods below as a source-obj argument.

> > > method
> > > (send a-syncheck-annotations syncheck:add-background-color |
> > > |  | source-obj |
> > > |  | start |
> > > |  | end |
> > > |  | color) |
> > → void?
> > source-obj : (not/c #f)
> > start : exact-nonnegative-integer?
> > end : exact-nonnegative-integer?
> > color : string?

> Called to indicate that the color color should be drawn on the background of the given range in the editor, when the mouse moves over it. This method is typically called in conjuction with some other method that provides some other annotation on the source.

> > > method
> > > (send a-syncheck-annotations syncheck:add-require-open-menu |
> > > |  | source-obj |
> > > |  | start |
> > > |  | end |
> > > |  | file) |
> > → void?
> > source-obj : (not/c #f)
> > start : exact-nonnegative-integer?
> > end : exact-nonnegative-integer?
> > file : path-string?

> Called to indicate that there is a require at the location from start to end, and that it corresponds to file. Check Syntax adds a popup menu.

> > > method
> > > (send a-syncheck-annotations syncheck:add-docs-menu |
> > > |  | source-obj |
> > > |  | start |
> > > |  | end |
> > > |  | id |
> > > |  | label |
> > > |  | path |
> > > |  | tag) |
> > → void?
> > source-obj : (not/c #f)
> > start : exact-nonnegative-integer?
> > end : exact-nonnegative-integer?
> > id : symbol?
> > label : any/c
> > path : any/c
> > tag : any/c

> Called to indicate that there is something that has documentation between the range start and end. The documented identifier’s name is given by id and the docs are found in the html file path at the html tag tag. The label argument describes the binding for use in the menu item (although it may be longer than 200 characters).

> > > method
> > > (send a-syncheck-annotations syncheck:add-id-set |
> > > |  | all-ids |
> > > |  | new-name-interferes?) |
> > → void?
> > | all-ids |  | : |  |
> > (listof (list/c (not/c #f)
> > exact-nonnegative-integer?
> > exact-nonnegative-integer?))
> > new-name-interferes? : (-> symbol boolean?)

> This method is no longer called by Check Syntax. It is here for backwards compatibility only. The information it provided must now be synthesized from the information supplied to syncheck:add-arrow/name-dup/pxpy.

> > > method
> > > (send a-syncheck-annotations syncheck:add-arrow |
> > > |  | start-source-obj |
> > > |  | start-left |
> > > |  | start-right |
> > > |  | end-source-obj |
> > > |  | end-left |
> > > |  | end-right |
> > > |  | actual? |
> > > |  | phase-level) |
> > → void?
> > start-source-obj : (not/c #f)
> > start-left : exact-nonnegative-integer?
> > start-right : exact-nonnegative-integer?
> > end-source-obj : (not/c #f)
> > end-left : exact-nonnegative-integer?
> > end-right : exact-nonnegative-integer?
> > actual? : boolean?
> > phase-level : (or/c exact-nonnegative-integer? #f)

> This function is not called directly anymore by Check Syntax. Instead syncheck:add-arrow/name-dup/pxpy is.

> This method is invoked by the default implementation of syncheck:add-arrow/name-dup in annotations-mixin.

> > > method
> > > (send a-syncheck-annotations syncheck:add-arrow/name-dup |
> > > |  | start-source-obj |
> > > |  | start-left |
> > > |  | start-right |
> > > |  | end-source-obj |
> > > |  | end-left |
> > > |  | end-right |
> > > |  | actual? |
> > > |  | phase-level |
> > > |  | require-arrow? |
> > > |  | name-dup?) |
> > → void?
> > start-source-obj : (not/c #f)
> > start-left : exact-nonnegative-integer?
> > start-right : exact-nonnegative-integer?
> > end-source-obj : (not/c #f)
> > end-left : exact-nonnegative-integer?
> > end-right : exact-nonnegative-integer?
> > actual? : boolean?
> > phase-level : (or/c exact-nonnegative-integer? #f)
> > require-arrow? : boolean?
> > name-dup? : (-> string? boolean?)

> This function is not called directly anymore by Check Syntax. Instead syncheck:add-arrow/name-dup/pxpy is.

> The default implementation of syncheck:add-arrow/name-dup/pxpy discards the start-px start-py end-px end-py arguments and calls this method.

> > > method
> > > (send a-syncheck-annotations syncheck:add-arrow/name-dup/pxpy |
> > > |  | start-source-obj |
> > > |  | start-left |
> > > |  | start-right |
> > > |  | start-px |
> > > |  | start-py |
> > > |  | end-source-obj |
> > > |  | end-left |
> > > |  | end-right |
> > > |  | end-px |
> > > |  | end-py |
> > > |  | actual? |
> > > |  | phase-level |
> > > |  | require-arrow |
> > > |  | name-dup?) |
> > → void?
> > start-source-obj : (not/c #f)
> > start-left : exact-nonnegative-integer?
> > start-right : exact-nonnegative-integer?
> > start-px : (real-in 0 1)
> > start-py : (real-in 0 1)
> > end-source-obj : (not/c #f)
> > end-left : exact-nonnegative-integer?
> > end-right : exact-nonnegative-integer?
> > end-px : (real-in 0 1)
> > end-py : (real-in 0 1)
> > actual? : boolean?
> > phase-level : (or/c exact-nonnegative-integer? #f)
> > require-arrow : (or/c boolean? 'module-lang-require)
> > name-dup? : (-> string? boolean?)

> Called to indicate that there should be an arrow between the locations described by the first ten arguments. The start-px and start-py indicate how far along the diagonal between the upper-left coordinate of the editor position start-left and the bottom-right of the editor position start-right to draw the foot of the arrow. The end-px and end-py indicate the same things for the head of the arrow.

> The phase-level argument indicates the phase of the binding and the actual? argument indicates if the binding is a real one, or a predicted one from a syntax template (predicted bindings are drawn with question marks in Check Syntax).

> The require-arrow argument indicates if this arrow points from an imported identifier to its corresponding require. Any true value means that it points to an import via require; #t means it was a normal require and 'module-lang-require means it comes from the implicit require that a module language provides.

> The name-dup? predicate returns #t in case that this variable (either the start or end), when replaced with the given string, would shadow some other binding (or otherwise interfere with the binding structure of the program at the time the program was expanded).

> Changed in version 1.1 of package drracket-tool-lib: Changed require-arrow to sometimes be 'module-lang-require.

> > > method
> > > (send a-syncheck-annotations syncheck:add-tail-arrow |
> > > |  | from-source-obj |
> > > |  | from-pos |
> > > |  | to-source-obj |
> > > |  | to-pos) |
> > → void?
> > from-source-obj : (not/c #f)
> > from-pos : exact-nonnegative-integer?
> > to-source-obj : (not/c #f)
> > to-pos : exact-nonnegative-integer?

> Called to indicate that there are two expressions, beginning at from-pos and to-pos that are in tail position with respect to each other.

> > > method
> > > (send a-syncheck-annotations syncheck:add-mouse-over-status |
> > > |  | source-obj |
> > > |  | pos-left |
> > > |  | pos-right |
> > > |  | str) |
> > → void?
> > source-obj : (not/c #f)
> > pos-left : exact-nonnegative-integer?
> > pos-right : exact-nonnegative-integer?
> > str : string?

> Called to indicate that the message in str should be shown when the mouse passes over the given position.

> > > method
> > > (send a-syncheck-annotations syncheck:add-prefixed-require-reference |
> > > |  | req-src |
> > > |  | req-pos-left |
> > > |  | req-pos-right) |
> > → void?
> > req-src : (not/c #f)
> > req-pos-left : exact-nonnegative-integer?
> > req-pos-right : exact-nonnegative-integer?

> This method is called for each require in the program that has a prefix or prefix-all-except around it in fully expanded form (i.e., it seems to come from a prefix-in or a similar form). The method is passed the location of the require in the original program.

> > > method
> > > (send a-syncheck-annotations syncheck:add-jump-to-definition |
> > > |  | source-obj |
> > > |  | start |
> > > |  | end |
> > > |  | id |
> > > |  | filename |
> > > |  | submods) |
> > → void?
> > source-obj : (not/c #f)
> > start : exact-nonnegative-integer?
> > end : exact-nonnegative-integer?
> > id : any/c
> > filename : path-string?
> > submods : (listof symbol?)

> Called to indicate that there is some identifier at the given location (named id) that is defined in the submods of the file filename (where an empty list in submods means that the identifier is defined at the top-level module).

> > > method
> > > (send a-syncheck-annotations syncheck:add-definition-target |
> > > |  | source-obj |
> > > |  | start |
> > > |  | finish |
> > > |  | style-name) |
> > → void?
> > source-obj : (not/c #f)
> > start : exact-nonnegative-integer?
> > finish : exact-nonnegative-integer?
> > style-name : any/c

> > > method
> > > (send a-syncheck-annotations syncheck:color-range |  | source-obj |
> > > |  | start |
> > > |  | finish |
> > > |  | style-name |
> > > |  | mode) |
> > → void?
> > source-obj : (not/c #f)
> > start : exact-nonnegative-integer?
> > finish : exact-nonnegative-integer?
> > style-name : any/c
> > mode : any/c

> Called to indicate that the given location should be colored according to the style style-name when in mode. The mode either indicates regular check syntax or is used indicate blame for potential contract violations (and still experimental).

> > > method
> > > (send a-syncheck-annotations syncheck:add-rename-menu |
> > > |  | id |
> > > |  | all-ids |
> > > |  | new-name-interferes?) |
> > → void?
> > id : symbol?
> > | all-ids |  | : |  |
> > (listof (list/c (not/c #f)
> > exact-nonnegative-integer?
> > exact-nonnegative-integer?))
> > new-name-interferes? : (-> symbol boolean?)

> This method is listed only for backwards compatibility. It is not called by Check Syntax anymore.

mixin annotations-mixin : (class? . -> . class?)
result implements: | syncheck-annotations<%>

Supplies all of the methods in syncheck-annotations<%> with default behavior. Be sure to use this mixin to future-proof your code and then override the methods you’re interested in.

By default:

- The syncheck:find-source-object method ignores its arguments and returns #f;

- the syncheck:add-arrow/name-dup method drops the require-arrow? and name-dup? arguments and calls syncheck:add-arrow;

- the syncheck:add-arrow/name-dup/pxpy method drops the from-px, from-py, to-px, and to-py arguments and calls syncheck:add-arrow/name-dup; and

- all of the other methods ignore their arguments and return (void).

Here is an example showing how use this library to extract all of the arrows that Check Syntax would draw from various expressions. One subtle point: arrows are only included when the corresponding identifiers are syntax-original?; the code below manages this by copying the properties from an identifier that is syntax-original? in the call to datum->syntax.

> > (define arrows-collector%
> (class (annotations-mixin object%)
> (super-new)
> (define/override (syncheck:find-source-object stx)
> stx)
> (define/override (syncheck:add-arrow/name-dup/pxpy
> start-source-obj start-left start-right start-px start-py
> end-source-obj end-left end-right end-px end-py
> actual? phase-level require-arrow? name-dup?)
> (set! arrows
> (cons (list start-source-obj end-source-obj)
> arrows)))
> (define arrows '())
> (define/public (get-collected-arrows) arrows)))
> > (define (arrows form)
> (define base-namespace (make-base-namespace))
> (define-values (add-syntax done)
> (make-traversal base-namespace #f))
> (define collector (new arrows-collector%))
> (parameterize ([current-annotations collector]
> [current-namespace base-namespace])
> (add-syntax (expand form))
> (done))
> (send collector get-collected-arrows))
> > (define (make-id name pos orig?)
> (datum->syntax
> #f
> name
> (list #f #f #f pos (string-length (symbol->string name)))
> (and orig? #'is-orig)))
> > (arrows `(λ (,(make-id 'x 1 #t)) ,(make-id 'x 2 #t)))
> '((#<syntax::1 x> #<syntax::2 x>))
> > (arrows `(λ (x) x))
> '()
> > (arrows `(λ (,(make-id 'x 1 #f)) ,(make-id 'x 2 #t)))
> '()
> > (arrows `(λ (,(make-id 'x 1 #t)) x))
> '()

> syntax syncheck:find-source-object

Bound to an identifier created with define-local-member-name that is used in syncheck-annotations<%>.

> syntax syncheck:add-background-color

Bound to an identifier created with define-local-member-name that is used in syncheck-annotations<%>.

> syntax syncheck:add-require-open-menu

Bound to an identifier created with define-local-member-name that is used in syncheck-annotations<%>.

> syntax syncheck:add-docs-menu

Bound to an identifier created with define-local-member-name that is used in syncheck-annotations<%>.

> syntax syncheck:add-rename-menu

Bound to an identifier created with define-local-member-name that is used in syncheck-annotations<%>.

> syntax syncheck:add-arrow

Bound to an identifier created with define-local-member-name that is used in syncheck-annotations<%>.

> syntax syncheck:add-arrow/name-dup

Bound to an identifier created with define-local-member-name that is used in syncheck-annotations<%>.

> syntax syncheck:add-arrow/name-dup/pxpy

Bound to an identifier created with define-local-member-name that is used in syncheck-annotations<%>.

> syntax syncheck:add-tail-arrow

Bound to an identifier created with define-local-member-name that is used in syncheck-annotations<%>.

> syntax syncheck:add-mouse-over-status

Bound to an identifier created with define-local-member-name that is used in syncheck-annotations<%>.

> syntax syncheck:add-jump-to-definition

Bound to an identifier created with define-local-member-name that is used in syncheck-annotations<%>.

> syntax syncheck:add-id-set

Bound to an identifier created with define-local-member-name that is used in syncheck-annotations<%>.

> syntax syncheck:color-range

Bound to an identifier created with define-local-member-name that is used in syncheck-annotations<%>.

> syntax syncheck:add-prefixed-require-reference

Bound to an identifier created with define-local-member-name that is used in syncheck-annotations<%>.
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