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Don't create extra lambdas when both results of (if ...) are trivial. 

Also map () directly to %nil, and allow (%if ...) to provide a value to a set! form.
This commit is contained in:
Jesse D. McDonald 2010-04-15 00:11:32 -05:00
parent 46b18c07d6
commit 8e147f7989
1 changed files with 10 additions and 7 deletions
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17
compiler.ss
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@ -23,7 +23,7 @@
(cdr form))]
[(%bind %if %tail-call %apply %lambda %set! %cons %car %cdr) form]
[else (simplify-funcall form)])
form))
(if (eq? form '()) '%nil form)))
(define (simplify-set! form)
(let ([value-form (simplify-form (third form))])
@ -33,7 +33,7 @@
(if (pair? after)
(cons subform after)
(if (or (not (pair? subform))
(memq (first subform) '(%apply %car %cdr %cons %bind)))
(memq (first subform) '(%apply %car %cdr %cons %bind %if)))
(list (simplify-set! `(set! ,(second form) ,subform)))
(list subform))))
'()
@ -125,11 +125,14 @@
(define-values (cond-expr true-expr false-expr)
(apply values (cdr form)))
(simplify-form
`(let ([,cond-val ,cond-expr]
[,true-fn (lambda () ,true-expr)]
[,false-fn (lambda () ,false-expr)])
(let ([,next-fn (%if ,cond-val ,true-fn ,false-fn)])
(%apply ,next-fn %nil)))))
(if (or (pair? true-expr) (pair? false-expr))
`(let ([,cond-val ,cond-expr]
[,true-fn (lambda () ,true-expr)]
[,false-fn (lambda () ,false-expr)])
(let ([,next-fn (%if ,cond-val ,true-fn ,false-fn)])
(%apply ,next-fn %nil)))
`(let ([,cond-val ,cond-expr])
(%if ,cond-val ,(simplify-form true-expr) ,(simplify-form false-expr))))))
; (lambda (required... [optional default-expr]... . rest) bodyexpr...)
; => (lambda argv