85 lines
3.6 KiB
Racket
85 lines
3.6 KiB
Racket
#lang scribble/manual
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@require[racket/require
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"utils.rkt"
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@for-label[phc-toolkit/stx]]
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@(def-orig typed [phc-toolkit/stx]
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stx-assoc
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identifier->string
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identifier→string
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quasisyntax/top-loc
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syntax/top-loc
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quasisyntax/whole-loc
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syntax/whole-loc)
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@title{Patching source locations}
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@(declare-exporting phc-toolkit/stx
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#:use-sources
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[(lib "phc-toolkit/stx/fold.rkt")])
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@defform[(quasisyntax/top-loc stx-expr quasitemplate)]{
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Like @racket[(quasisyntax/loc stx-expr quasitemplate)], but the source
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location for all "top" parts of the resulting syntax object are updated, so
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long as their source location is the same as the source location for the
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topmost part of the @racket[quasitemplate].
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In other words, this does a traversal of the syntax object and updates the
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source location of the traversed parts, but the traversal does not go within a
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part whose source file differs from that of the @racket[quasitemplate].
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For example, in the following code, the source location of parts within
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@racket[user-code] will not be updated (unless @racket[user-code] originates
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from the same file as @racket[quasitemplate]), but the source location of all
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other parts will be updated, including the @racket[begin] identifier and its
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surrounding form (its surrounding "pair of parentheses"). In contrast,
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@racket[quasisyntax/loc] would have updated only the topmost syntax object,
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i.e. the outermost "pair of parentheses" of the @racket[let] form.
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@racketblock[(λ (stx)
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(syntax-case stx ()
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[(_ . user-code)
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(with-syntax ([bg #'(begin . user-code)])
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(quasisyntax/top-loc stx (let () bg)))]))]}
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@defform[(syntax/top-loc stx-expr quasitemplate)]{
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Like @racket[(syntax/loc stx-expr quasitemplate)], but the source location
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for all "top" parts of the resulting syntax object are updated, like is done
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by @racket[quasisyntax/top-loc].}
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@defform[(quasisyntax/whole-loc stx-expr quasitemplate)]{
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Like @racket[(quasisyntax/top-loc stx-expr quasitemplate)], but the source
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location for all parts of the resulting syntax object are updated if they
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belong to the same source file as the @racket[quasitemplate], not only the
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"top" ones.
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In the following example, all parts of the syntax object which source file is
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the same as the macro will be updated, including those within
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@racket[user-code] (e.g. if the @racket[user-code] contains code generated by
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other macros from the same file.
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@racketblock[(λ (stx)
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(syntax-case stx ()
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[(_ . user-code)
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(with-syntax ([bg #'(begin . user-code)])
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(quasisyntax/whole-loc stx (let () bg)))]))]
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This is usually not needed, as @racket[quasisyntax/top-loc] would have
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updated the source location of @racket[1], @racket[2] and @racket[3] and their
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surrounding syntax list (the "pair of parentheses" around them), since their
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surrounding syntax list comes from the same file as the macro:
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@racketblock[(λ (stx)
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(syntax-case stx ()
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[(_ . user-function)
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(quasisyntax/top-loc stx
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(user-function 1 2 3))]))]}
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@defform[(syntax/whole-loc stx-expr quasitemplate)]{
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Like @racket[(syntax/top-loc stx-expr quasitemplate)], but the source
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location for all parts of the resulting syntax object are updated if they
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belong to the same source file as the @racket[quasitemplate], not only the
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"top" ones, like is done by @racket[quasisyntax/whole-loc].}
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