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syntax/parse: simplify head pattern compilation

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The continuation expression for a head pattern evaluates to a
procedure that takes the rest of the term and the current progress.
This commit is contained in:
Ryan Culpepper 2018-08-09 18:30:32 +02:00
parent 6e46dd1b0d
commit 39bacd45d5
1 changed files with 6 additions and 9 deletions
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15
racket/collects/syntax/parse/private/parse.rkt
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@ -539,11 +539,8 @@ Conventions:
(syntax-case stx ()
[(parse:S x cx pattern0 pr es k)
(syntax-case #'pattern0 ()
[#s(internal-rest-pattern rest-x rest-cx rest-pr)
#`(let ([rest-x x]
[rest-cx cx]
[rest-pr pr])
k)]
[#s(internal-rest-pattern)
#`(k x cx pr)]
[#s(pat:any)
#'k]
[#s(pat:svar name)
@ -924,8 +921,8 @@ Conventions:
(with-syntax ([pattern
(convert-list-pattern
#'pattern
#'#s(internal-rest-pattern rest-x rest-cx rest-pr))])
#'(parse:S x cx pattern pr es k))]
#'#s(internal-rest-pattern))])
#'(parse:S x cx pattern pr es (lambda (rest-x rest-cx rest-pr) k)))]
[#s(hpat:action action subpattern)
#'(parse:A x cx action pr es (parse:H x cx rest-x rest-cx rest-pr subpattern pr es k))]
[#s(hpat:delimit pattern)
@ -975,8 +972,8 @@ Conventions:
[_
#'(parse:S x cx
;; FIXME: consider proper-list-pattern? (yes is consistent with ~seq)
#s(pat:pair head #s(internal-rest-pattern rest-x rest-cx rest-pr))
pr es k)])]))
#s(pat:pair head #s(internal-rest-pattern))
pr es (lambda (rest-x rest-cx rest-pr) k))])]))
;; (parse:dots x cx EH-pattern S-pattern pr es k) : expr[Ans]
;; In k: attrs(EH-pattern, S-pattern) are bound.