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.
80 lines
2.5 KiB
Racket
80 lines
2.5 KiB
Racket
#lang racket/base
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(require "machine.rkt"
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"re-help.rkt"
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racket/match
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(for-syntax syntax/parse
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racket/syntax
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unstable/syntax
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racket/base
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"re-help.rkt"
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"re-compile.rkt"))
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(define-syntax-rule (define-re-transformer id lam)
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(define-syntax id (re-transformer lam)))
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(define-for-syntax code-insp (variable-reference->module-declaration-inspector
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(#%variable-reference)))
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(define-for-syntax (re-expand stx)
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(syntax-parse
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(syntax-disarm stx code-insp)
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#:literals (complement seq union star epsilon nullset dseq rec unquote)
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[((~and op complement) lhs:expr)
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(quasisyntax/loc stx
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(op #,(re-expand #'lhs)))]
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[((~and op rec) v:id lhs:expr)
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(quasisyntax/loc stx
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(op v #,(re-expand #'lhs)))]
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[((~and op unquote) e:expr)
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(quasisyntax/loc stx
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(op e))]
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[((~and op star) lhs:expr)
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(quasisyntax/loc stx
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(op #,(re-expand #'lhs)))]
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[((~and op seq) lhs:expr)
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(re-expand #'lhs)]
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[((~and op seq) lhs:expr rhs:expr)
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(quasisyntax/loc stx
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(op #,(re-expand #'lhs) #,(re-expand #'rhs)))]
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[((~and op seq) lhs:expr rest:expr ...)
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(quasisyntax/loc stx
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#,(re-expand #'(op lhs (op rest ...))))]
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[((~and op union) lhs:expr)
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(re-expand #'lhs)]
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[((~and op union) lhs:expr rhs:expr)
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(quasisyntax/loc stx
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(op #,(re-expand #'lhs) #,(re-expand #'rhs)))]
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[((~and op union) lhs:expr rest:expr ...)
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(quasisyntax/loc stx
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#,(re-expand #'(op lhs (op rest ...))))]
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[(~and e (~var transformer (static re-transformer? "re transformer")))
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(record-disappeared-uses (list #'transformer))
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(quasisyntax/loc stx
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#,(re-expand ((re-transformer->re (attribute transformer.value)) #'e)))]
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[(~and e ((~var transformer (static re-transformer? "re transformer")) . _))
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(record-disappeared-uses (list #'transformer))
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(quasisyntax/loc stx
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#,(re-expand ((re-transformer->re (attribute transformer.value)) #'e)))]
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[((~and op dseq) pat:expr rhs:expr)
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(quasisyntax/loc stx
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(op pat #,(re-expand #'rhs)))]
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[_
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stx]))
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(define-for-syntax (re-compile stx)
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(syntax-parse
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stx
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[the-re:sre
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(attribute the-re.best)]))
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(define-syntax (re stx)
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(with-disappeared-uses
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(syntax-case stx ()
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[(_ the-re)
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(re-compile (re-expand #'the-re))])))
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(provide
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complement seq union star epsilon nullset dseq rec unquote
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define-re-transformer
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re)
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