2d35c9d6cf
* README.md: added some small documentation and loop expansion. * goof.scm: Changed the iterator protocol to not use unnecessary :acc and :fors. * iterators.scm: see above. * ref-let.scm: a new macro to allow multiple values and pattern matching to co-exist for body-bindings.
51 lines
1.6 KiB
Scheme
51 lines
1.6 KiB
Scheme
(define-module (ref-let)
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#:export (ref-let)
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#:use-module (ice-9 match)
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#:use-module (srfi srfi-71))
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(define-syntax ref-let
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(syntax-rules ()
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((ref-let ids body ...)
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(rl () () ids body ...))))
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(define-syntax rl
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(syntax-rules (values)
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;; emit simple case, no match
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((_ (lets ...) () () body ...)
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(let (lets ...)
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body ...))
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;; emit, hard case.
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((rl (lets ...) (matches ...) () body ...)
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(let (lets ...)
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(match-let (matches ...)
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body ...)))
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;; a (values ...) clause:
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((rl (l ...) m (((values . v) expr) . clause-rest) . body)
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(rl (l ... ((values . v) expr)) m clause-rest . body))
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;; Simple cases
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;; (rl ((a 5)) () (((b . _) (cons 1 2))) (+ a b))
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((_ (l ...) (m ...) (((p . p-rest) expr) . clause-rest) body ...)
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(rl (l ... (dummy expr)) (m ... ((p . p-rest) dummy)) clause-rest body ...))
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((rl (l ...) (m ...) ((binding expr) . clause-rest) body ...)
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(rl (l ... (binding expr)) (m ...) clause-rest body ...))
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;; More than one id
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((rl l m ((id id* ... expr) . clause-rest) . body)
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(extract () () (id id* ... expr) l m clause-rest . body))))
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(define-syntax extract
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(syntax-rules ()
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((_ let-binding (match-bindings ...) () (l ...) (m ...) clauses . body)
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(rl (l ... let-binding) (m ... match-bindings ...) clauses . body))
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((_ (lb ...) mb (expr) . rest)
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(extract (lb ... expr) mb () . rest))
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;; Pattern
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((_ (lb ...) (mb ...) ((p . p-rest) ids ...) . rest)
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(extract (lb ... dummy) (mb ... ((p . p-rest) dummy)) (ids ...) . rest))
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((_ (lb ...) mb (id ids ...) . rest)
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(extract (lb ... id) mb (ids ...) . rest))))
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