0197902309
Macros and other tools that need syntax privilege used `(current-code-inspector)' at the module top-level to try to capture the right code inspector at load time. It's more consistent to instead use the enclosing module's declaration-time inspector, and `var-ref->mod-decl-insp' provides that. The new function works only on references to anonymous variables, which limits access to the inspector. The real function name is longer, of course.
20 lines
710 B
Racket
20 lines
710 B
Racket
#lang scribble/doc
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@(require "common.rkt" (for-label syntax/free-vars))
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@title[#:tag "free-vars"]{Computing the Free Variables of an Expression}
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@defmodule[syntax/free-vars]
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@defproc[(free-vars [expr-stx syntax?] [insp inspector? _mod-decl-insp])
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(listof identifier?)]{
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Returns a list of free @racket[lambda]- and @racket[let]-bound
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identifiers in @racket[expr-stx]. The expression must be fully
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expanded (see @secref[#:doc refman "fully-expanded"] and
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@racket[expand]).
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The inspector @racket[insp] is used to disarm @racket[expr-stx] and
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sub-expressions before extracting idenrifiers. The default
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@racket[insp] is the declaration-time inspector of the
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@racketmodname[syntax/free-vars] module.}
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