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syntax/parse: add pattern-has-cut?

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This commit is contained in:
Ryan Culpepper 2016-12-01 21:52:07 -05:00
parent db8d8f8d75
commit e676ba74a5
1 changed files with 63 additions and 0 deletions
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63
racket/collects/syntax/parse/private/rep-patterns.rkt
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@ -308,6 +308,69 @@ A RepConstraint is one of
;; ----
;; pattern-has-cut? : *Pattern -> Boolean
;; Returns #t if p *might* cut (~!, not within ~delimit-cut).
(define (pattern-has-cut? p)
(match p
;; -- S patterns
[(pat:any) #f]
[(pat:svar name) #f]
[(pat:var/p name _ _ _ _ _ _ _)
;; FIXME: need delimit-cut? info from stxclass
#f]
[(pat:reflect _ _ _ name nested-attrs) #f]
[(pat:datum _) #f]
[(pat:literal _ _ _) #f]
[(pat:action a sp) (or (pattern-has-cut? a) (pattern-has-cut? sp))]
[(pat:head headp tailp) (or (pattern-has-cut? headp) (pattern-has-cut? tailp))]
[(pat:pair headp tailp) (or (pattern-has-cut? headp) (pattern-has-cut? tailp))]
[(pat:vector sp) (pattern-has-cut? sp)]
[(pat:box sp) (pattern-has-cut? sp)]
[(pat:pstruct key sp) (pattern-has-cut? sp)]
[(pat:describe sp _ _ _) (pattern-has-cut? sp)]
[(pat:and ps) (ormap pattern-has-cut? ps)]
[(pat:or _ ps _) (ormap pattern-has-cut? ps)]
[(pat:not _) #f]
[(pat:dots headps tailp) (or (ormap pattern-has-cut? headps) (pattern-has-cut? tailp))]
[(pat:delimit sp) #f]
[(pat:commit sp) #f]
[(pat:ord sp _ _) (pattern-has-cut? sp)]
[(pat:post sp) (pattern-has-cut? sp)]
[(pat:integrated name _ _ _) #f]
;; -- A patterns
[(action:cut) #t]
[(action:fail _ _) #f]
[(action:bind attr expr) #f]
[(action:and ps) (ormap pattern-has-cut? ps)]
[(action:parse sp _) (pattern-has-cut? sp)]
[(action:do _) #f]
[(action:ord sp _ _) (pattern-has-cut? sp)]
[(action:post sp) (pattern-has-cut? sp)]
;; -- H patterns
[(hpat:var/p name _ _ _ _ _ _ _)
;; FIXME: need delimit-cut?
#f]
[(hpat:reflect _ _ _ name nested-attrs) #f]
[(hpat:seq lp) (pattern-has-cut? lp)]
[(hpat:action a hp) (or (pattern-has-cut? a) (pattern-has-cut? hp))]
[(hpat:describe hp _ _ _) (pattern-has-cut? hp)]
[(hpat:and hp sp) (or (pattern-has-cut? hp) (pattern-has-cut? sp))]
[(hpat:or _ ps _) (ormap pattern-has-cut? ps)]
[(hpat:delimit hp) #f]
[(hpat:commit hp) #f]
[(hpat:ord hp _ _) (pattern-has-cut? hp)]
[(hpat:post hp) (pattern-has-cut? hp)]
[(hpat:peek hp) (pattern-has-cut? hp)]
[(hpat:peek-not hp) (pattern-has-cut? hp)]
;; EH patterns
[(ehpat _ hp _ _) (pattern-has-cut? hp)]
))
;; ----
(define (create-pat:or ps)
(define attrss (map pattern-attrs ps))
(pat:or (union-iattrs attrss) ps attrss))