diff options
Diffstat (limited to 'module/ice-9')
-rw-r--r-- | module/ice-9/boot-9.scm | 192 |
1 files changed, 135 insertions, 57 deletions
diff --git a/module/ice-9/boot-9.scm b/module/ice-9/boot-9.scm index e929c4d58..a7cd47ae1 100644 --- a/module/ice-9/boot-9.scm +++ b/module/ice-9/boot-9.scm @@ -411,70 +411,150 @@ If there is no handler at all, Guile prints an error and then exits." ((_ x) x) ((_ x y ...) (let ((t x)) (if t t (or y ...)))))) +(include-from-path "ice-9/quasisyntax") + (define-syntax-rule (when test stmt stmt* ...) (if test (begin stmt stmt* ...))) (define-syntax-rule (unless test stmt stmt* ...) (if (not test) (begin stmt stmt* ...))) -;; The "maybe-more" bits are something of a hack, so that we can support -;; SRFI-61. Rewrites into a standalone syntax-case macro would be -;; appreciated. (define-syntax cond - (syntax-rules (=> else) - ((_ "maybe-more" test consequent) - (if test consequent)) - - ((_ "maybe-more" test consequent clause ...) - (if test consequent (cond clause ...))) - - ((_ (else else1 else2 ...)) - (begin else1 else2 ...)) - - ((_ (test => receiver) more-clause ...) - (let ((t test)) - (cond "maybe-more" t (receiver t) more-clause ...))) - - ((_ (generator guard => receiver) more-clause ...) - (call-with-values (lambda () generator) - (lambda t - (cond "maybe-more" - (apply guard t) (apply receiver t) more-clause ...)))) - - ((_ (test => receiver ...) more-clause ...) - (syntax-violation 'cond "wrong number of receiver expressions" - '(test => receiver ...))) - ((_ (generator guard => receiver ...) more-clause ...) - (syntax-violation 'cond "wrong number of receiver expressions" - '(generator guard => receiver ...))) - - ((_ (test) more-clause ...) - (let ((t test)) - (cond "maybe-more" t t more-clause ...))) - - ((_ (test body1 body2 ...) more-clause ...) - (cond "maybe-more" - test (begin body1 body2 ...) more-clause ...)))) + (lambda (whole-expr) + (define (fold f seed xs) + (let loop ((xs xs) (seed seed)) + (if (null? xs) seed + (loop (cdr xs) (f (car xs) seed))))) + (define (reverse-map f xs) + (fold (lambda (x seed) (cons (f x) seed)) + '() xs)) + (syntax-case whole-expr () + ((_ clause clauses ...) + #`(begin + #,@(fold (lambda (clause-builder tail) + (clause-builder tail)) + #'() + (reverse-map + (lambda (clause) + (define* (bad-clause #:optional (msg "invalid clause")) + (syntax-violation 'cond msg whole-expr clause)) + (syntax-case clause (=> else) + ((else e e* ...) + (lambda (tail) + (if (null? tail) + #'((begin e e* ...)) + (bad-clause "else must be the last clause")))) + ((else . _) (bad-clause)) + ((test => receiver) + (lambda (tail) + #`((let ((t test)) + (if t + (receiver t) + #,@tail))))) + ((test => receiver ...) + (bad-clause "wrong number of receiver expressions")) + ((generator guard => receiver) + (lambda (tail) + #`((call-with-values (lambda () generator) + (lambda vals + (if (apply guard vals) + (apply receiver vals) + #,@tail)))))) + ((generator guard => receiver ...) + (bad-clause "wrong number of receiver expressions")) + ((test) + (lambda (tail) + #`((let ((t test)) + (if t t #,@tail))))) + ((test e e* ...) + (lambda (tail) + #`((if test + (begin e e* ...) + #,@tail)))) + (_ (bad-clause)))) + #'(clause clauses ...)))))))) (define-syntax case - (syntax-rules (else) - ((case (key ...) - clauses ...) - (let ((atom-key (key ...))) - (case atom-key clauses ...))) - ((case key - (else result1 result2 ...)) - (begin result1 result2 ...)) - ((case key - ((atoms ...) result1 result2 ...)) - (if (memv key '(atoms ...)) - (begin result1 result2 ...))) - ((case key - ((atoms ...) result1 result2 ...) - clause clauses ...) - (if (memv key '(atoms ...)) - (begin result1 result2 ...) - (case key clause clauses ...))))) + (lambda (whole-expr) + (define (fold f seed xs) + (let loop ((xs xs) (seed seed)) + (if (null? xs) seed + (loop (cdr xs) (f (car xs) seed))))) + (define (fold2 f a b xs) + (let loop ((xs xs) (a a) (b b)) + (if (null? xs) (values a b) + (call-with-values + (lambda () (f (car xs) a b)) + (lambda (a b) + (loop (cdr xs) a b)))))) + (define (reverse-map-with-seed f seed xs) + (fold2 (lambda (x ys seed) + (call-with-values + (lambda () (f x seed)) + (lambda (y seed) + (values (cons y ys) seed)))) + '() seed xs)) + (syntax-case whole-expr () + ((_ expr clause clauses ...) + (with-syntax ((key #'key)) + #`(let ((key expr)) + #,@(fold + (lambda (clause-builder tail) + (clause-builder tail)) + #'() + (reverse-map-with-seed + (lambda (clause seen) + (define* (bad-clause #:optional (msg "invalid clause")) + (syntax-violation 'case msg whole-expr clause)) + (syntax-case clause () + ((test . rest) + (with-syntax + ((clause-expr + (syntax-case #'rest (=>) + ((=> receiver) #'(receiver key)) + ((=> receiver ...) + (bad-clause + "wrong number of receiver expressions")) + ((e e* ...) #'(begin e e* ...)) + (_ (bad-clause))))) + (syntax-case #'test (else) + ((datums ...) + (let ((seen + (fold + (lambda (datum seen) + (define (warn-datum type) + ((@ (system base message) + warning) + type + (append (source-properties datum) + (source-properties + (syntax->datum #'test))) + datum + (syntax->datum clause) + (syntax->datum whole-expr))) + (if (memv datum seen) + (warn-datum 'duplicate-case-datum)) + (if (or (pair? datum) + (array? datum) + (generalized-vector? datum)) + (warn-datum 'bad-case-datum)) + (cons datum seen)) + seen + (map syntax->datum #'(datums ...))))) + (values (lambda (tail) + #`((if (memv key '(datums ...)) + clause-expr + #,@tail))) + seen))) + (else (values (lambda (tail) + (if (null? tail) + #'(clause-expr) + (bad-clause + "else must be the last clause"))) + seen)) + (_ (bad-clause))))) + (_ (bad-clause)))) + '() #'(clause clauses ...))))))))) (define-syntax do (syntax-rules () @@ -502,8 +582,6 @@ If there is no handler at all, Guile prints an error and then exits." (define-syntax-rule (delay exp) (make-promise (lambda () exp))) -(include-from-path "ice-9/quasisyntax") - (define-syntax current-source-location (lambda (x) (syntax-case x () |