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egison.scm
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egison.scm
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;(define-module egison
; (export match-all
; match-first
; Something
; Eq
; Integer
; List
; Multiset
; ))
;(select-module egison)
(use util.match)
(use srfi-1)
(define-macro (match-all t M . clauses)
(if (eq? clauses '())
'()
(let* {[clause (car clauses)]
[p (list 'quasiquote (rewrite-pattern (car clause)))]
[es (cdr clause)]}
`(append (map (lambda (ret) (apply (lambda ,(extract-pattern-variables p) . ,es) ret))
(gen-match-results ,p ,M ,t))
(match-all ,t ,M . ,(cdr clauses))))))
(define-macro (match-first t M . clauses)
(if (eq? clauses '())
'exhausted-match-clauses
(let* {[clause (car clauses)]
[p (list 'quasiquote (rewrite-pattern (car clause)))]
[es (cdr clause)]}
`(let {[rets (gen-first-match-result ,p ,M ,t)]}
(if (eq? rets '())
(match-first ,t ,M . ,(cdr clauses))
(apply (lambda ,(extract-pattern-variables p) ,(cons 'begin es)) (car rets)))))))
; `(let {[rets (map (lambda (ret) (apply (lambda ,(extract-pattern-variables p) ,(cons 'begin es)) ret)) (gen-first-match-result ,p ,M ,t))]}
; (if (eq? rets '())
; (match-first ,t ,M . ,(cdr clauses))
; (car rets))))))
(define rewrite-pattern
(lambda (p)
(let {[ret (rewrite-pattern-helper p '())]}
(car (rewrite-later-pattern-helper (car ret) (cdr ret))))))
(define rewrite-pattern-helper
(lambda (p xs)
(match p
(('unquote q) (cons (list 'val (list 'unquote `(lambda ,xs ,q))) xs))
(('quasiquote q) (cons (list 'val (list 'unquote `(lambda ,xs ,q))) xs))
(('pred q) (cons (list 'pred (list 'unquote `(lambda ,xs ,q))) xs))
(('quote (? list? ps))
(let {[ret (rewrite-patterns-helper ps xs)]}
(cons `(quote ,(car ret)) (cdr ret))))
(('later p) (cons `(later ,p) xs))
((c . args)
(let {[ret (rewrite-patterns-helper args xs)]}
(cons `(,c . ,(car ret)) (cdr ret))))
('_ (cons '_ xs))
(pvar (cons pvar (append xs `(,pvar)))))))
(define rewrite-patterns-helper
(lambda (ps xs)
(match ps
(() (cons '() xs))
((p . qs)
(let* {[ret (rewrite-pattern-helper p xs)]
[p2 (car ret)]
[xs2 (cdr ret)]
[ret2 (rewrite-patterns-helper qs xs2)]
[qs2 (car ret2)]
[ys (cdr ret2)]}
(cons (cons p2 qs2) ys))))))
(define rewrite-later-pattern-helper
(lambda (p xs)
(match p
(('later p)
(let {[ret (rewrite-pattern-helper p xs)]}
(cons `(later ,(car ret)) (cdr ret))))
((c . args)
(let {[ret (rewrite-later-patterns-helper args xs)]}
(cons `(,c . ,(car ret)) (cdr ret))))
(_ (cons p xs)))))
(define rewrite-later-patterns-helper
(lambda (ps xs)
(match ps
(() (cons '() xs))
((p . qs)
(let* {[ret (rewrite-later-pattern-helper p xs)]
[p2 (car ret)]
[xs2 (cdr ret)]
[ret2 (rewrite-later-patterns-helper qs xs2)]
[qs2 (car ret2)]
[ys (cdr ret2)]}
(cons (cons p2 qs2) ys))))))
(define extract-pattern-variables
(lambda (p)
(match p
(('val _) '())
(('pred _) '())
(('or pat . _) (extract-pattern-variables pat))
(('quote args)
(concatenate (map extract-pattern-variables args)))
((c . args)
(concatenate (map extract-pattern-variables args)))
(() '())
('_ '())
(pvar `(,pvar))
)))
(define gen-match-results
(lambda (p M t)
(processMStates `{(MState {[,p ,M ,t]} {})})))
(define gen-first-match-result
(lambda (p M t)
(processMStates1 `{(MState {[,p ,M ,t]} {})})))
(define processMStates
(lambda (mStates)
(match mStates
(() '())
((('MState '{} ret) . rs)
(cons ret (processMStates rs)))
((mState . rs)
(processMStates (append (processMState mState) rs)))
)))
(define processMStates1
(lambda (mStates)
(match mStates
(() '())
((('MState '{} ret) . rs)
`(,ret))
((mState . rs)
(processMStates1 (append (processMState mState) rs)))
)))
(define processMState
(lambda (mState)
(match mState
(('MState {[('quote (? list? ps)) (? list? Ms) ts] . mStack} ret)
(list `(MState ,(append (zip3 ps Ms ts) mStack) ,ret)))
(('MState {[p (? list? Ms) t] . mStack} ret)
(list `(MState ,(cons `(,p Something ,t) mStack) ,ret)))
(('MState {[('val f) M t] . mStack} ret)
(let {[next-matomss (M `(val ,(apply f ret)) t)]}
(map (lambda (next-matoms) `(MState ,(append next-matoms mStack) ,ret)) next-matomss)))
(('MState {[('pred f) _ t] . mStack} ret)
(if ((apply f ret) t)
(list `(MState ,mStack ,ret))
'()))
(('MState {[('and . ps) M t] . mStack} ret)
(let {[next-matoms (map (lambda (p) `[,p ,M ,t]) ps)]}
(list `(MState ,(append next-matoms mStack) ,ret))))
(('MState {[('or . ps) M t] . mStack} ret)
(let {[next-matomss (map (lambda (p) `{[,p ,M ,t]}) ps)]}
(map (lambda (next-matoms) `(MState ,(append next-matoms mStack) ,ret)) next-matomss)))
(('MState {[('not p) M t] . mStack} ret)
(if (null? (processMStates (list `(MState {[,p ,M ,t]} ,ret))))
(list `(MState ,mStack ,ret))
'()))
(('MState {[('later p) M t] . mStack} ret)
(list `(MState ,(append mStack `{[,p ,M ,t]}) ,ret)))
(('MState {['_ 'Something t] . mStack} ret)
`((MState ,mStack ,ret)))
(('MState {[pvar 'Something t] . mStack} ret)
`((MState ,mStack ,(append ret `(,t)))))
(('MState {[p M t] . mStack} ret)
(let {[next-matomss (M p t)]}
(map (lambda (next-matoms) `(MState ,(append next-matoms mStack) ,ret)) next-matomss)))
)))
(define Something 'Something)
(define Eq
(lambda (p t)
(match p
(('val x)
(if (equal? x t)
'(())
'()))
(pvar
`(((,pvar Something ,t))))
)))
(define Integer Eq)
(define List
(lambda (M)
(lambda (p t)
(match p
(('nil) (if (eq? t '()) '{{}} '{}))
(('cons px py)
(match t
(() '{})
((x . xs)
`{{[,px ,M ,x] [,py ,(List M) ,xs]}})))
(('join '_ py)
(map (lambda (y) `{[,py ,(List M) ,y]})
(tails t)))
(('join px py)
(map (lambda (xy) `{[,px ,(List M) ,(car xy)] [,py ,(List M) ,(cadr xy)]})
(unjoin t)))
(('val x) (if (eq? x t) '{{}} '{}))
(pvar `{{[,pvar Something ,t]}})))))
(define tails
(lambda (xs)
(if (eq? xs '())
'(())
(cons xs (tails (cdr xs))))))
(define unjoin
(lambda (xs)
(unjoin-helper '((() ())) xs)))
(define unjoin-helper
(lambda (ret xs)
(match xs
(() ret)
((y . ys)
(cons `(() ,xs) (map (lambda (p) `(,(cons y (car p)) ,(cadr p))) (unjoin ys))))
)))
(define Multiset
(lambda (M)
(lambda (p t)
(match p
[('nil) (if (eq? t '{}) '{{}} '{})]
[('cons px '_) (map (lambda (x) `{[,px ,M ,x]}) t)]
[('cons px py)
(map (lambda (xy) `{[,px ,M ,(car xy)] [,py ,(Multiset M) ,(cadr xy)]})
(match-all t (List M)
[(join hs (cons x ts)) `[,x ,(append hs ts)]]))]
[('val v)
(match-first `[,t ,v] `[,(List M) ,(Multiset M)]
['[(nil) (nil)] '{{}}]
['[(cons x xs) (cons ,x ,xs)] '{{}}]
['[_ _] '{}])]
[pvar `{{[,pvar Something ,t]}}]))))
;;
;; Utility functions
;;
(define zip3
(lambda [xs ys zs]
(match `(,xs ,ys ,zs)
((() _ _) '())
((_ () _) '())
((_ _ ()) '())
(((x . xs) (y . ys) (z . zs)) (cons `(,x ,y ,z) (zip3 xs ys zs))))))