d7a87c79e0
Changed backtracking algorithm, runtime representations
- syntax classes, ~describe no longer implicitly commit
- ~describe no longer delimits effect of cut
Added keyword & optional args for stxclasses
Added ~do and #:do, ~post, ~commit and #:commit,
~delimit-cut and #:no-delimit-cut
Added syntax/parse/debug, syntax/parse/experimental/*
- expr/c for contracting macro sub-expressions
moved from syntax/parse to syntax/parse/experimental/contract
- syntax class reflection (~reflect, ~splicing-reflect)
- eh-alternative-sets (~eh-var)
- provide-syntax-class/contract
(only for params, not attrs so far)
Changed ~fail to not include POST progress (#:fail still does)
old (~fail _) is now (~post (~fail _))
Made msg argument of ~fail optional
Removed generic "repetition constraint violated" msg
Removed atom-in-list stxclass
Removed unnecessary datum->syntax on cdr of pair pattern
massive improvements to long-list microbenchmarks
Optimization: integrable syntax classes (id, expr, keyword)
need better measurements
Optimization: ad hoc elimination of head/tail choice point
for (EH ... . ()) patterns
Added unstable/wrapc (proc version of expr/c)
79 lines
4.1 KiB
Racket
79 lines
4.1 KiB
Racket
#lang racket/base
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(require (for-syntax racket/base
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syntax/parse
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unstable/syntax
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"../private/minimatch.rkt"
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"../private/rep.rkt"
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"../private/rep-data.rkt"
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"../private/rep-patterns.rkt"
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"../private/kws.rkt")
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"../private/keywords.rkt"
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"../private/sc.rkt")
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(provide ~eh-var
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define-eh-alternative-set)
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(define-syntax (define-eh-alternative-set stx)
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(define-syntax-class alt
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#:description "eh-alternate-set alternative"
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#:literals (pattern)
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(pattern (pattern alt)))
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(syntax-parse stx
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#:literals (pattern)
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[(_ name:id a:alt ...)
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(parameterize ((current-syntax-context stx))
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(let* ([decls (new-declenv null #:conventions null)]
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[ehpat+hstx-list
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(apply append
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(for/list ([alt (in-list (syntax->list #'(a.alt ...)))])
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(parse*-ellipsis-head-pattern alt decls #t #:context stx)))]
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[eh-alt+defs-list
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(for/list ([ehpat+hstx (in-list ehpat+hstx-list)])
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(let ([ehpat (car ehpat+hstx)]
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[hstx (cadr ehpat+hstx)])
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(cond [(syntax? hstx)
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(with-syntax ([(parser) (generate-temporaries '(eh-alt-parser))])
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(let ([attrs (iattrs->sattrs (pattern-attrs (ehpat-head ehpat)))])
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(list (eh-alternative (ehpat-repc ehpat) attrs #'parser)
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(list #`(define parser
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(parser/rhs parser () #,attrs
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[#:description #f (pattern #,hstx)]
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#t
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#,stx))))))]
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[(eh-alternative? hstx)
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(list hstx null)]
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[else
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(error 'define-eh-alternative-set "internal error: unexpected ~e"
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hstx)])))]
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[eh-alts (map car eh-alt+defs-list)]
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[defs (apply append (map cadr eh-alt+defs-list))])
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(with-syntax ([(def ...) defs]
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[(alt-expr ...)
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(for/list ([alt (in-list eh-alts)])
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(with-syntax ([repc-expr
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(match (eh-alternative-repc alt)
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['#f
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#'(quote #f)]
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[(rep:once n u o)
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#`(rep:once (quote-syntax #,n)
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(quote-syntax #,u)
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(quote-syntax #,o))]
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[(rep:optional n o d)
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#`(rep:optional (quote-syntax #,n)
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(quote-syntax #,o)
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(quote-syntax #,d))]
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[(rep:bounds min max n u o)
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#`(rep:bounds (quote #,min)
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(quote #,max)
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(quote-syntax #,n)
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(quote-syntax #,u)
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(quote-syntax #,o))])]
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[attrs-expr
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#`(quote #,(eh-alternative-attrs alt))]
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[parser-expr
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#`(quote-syntax #,(eh-alternative-parser alt))])
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#'(eh-alternative repc-expr attrs-expr parser-expr)))])
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#'(begin def ...
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(define-syntax name
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(eh-alternative-set (list alt-expr ...)))))))]))
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