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* From: Shiro Kawai <shiro@xxxxxxxx> * Date: Thu, 06 Apr 2006 14:01:48 -1000 (HST) * Subj: Re: Request for Clarification on Rationale | I feel this comparison is somewhat skewed. The typical | situation where I use multiple values is: | - multiple values are generated for every iteration, | so mm vs vv test is more close, and | - the expression body of generating multiple values are | known, so I'd rather use srfi-8's RECEIVE. | And this is the result on Gauche 0.8.6 / P4 2GHz (I use 100times | more iterations as William Clinger did.) gosh> (time (for-each (lambda (x) ((mm x) list)) (make-list 10000000 1))) | ; real 19.542 | ; user 19.480 | ; sys 0.060 gosh> (time (for-each (lambda (x) (call-with-values (lambda () (vv x)) list)) (make-list 10000000 1))) | ; real 26.579 | ; user 26.460 | ; sys 0.110 gosh> (time (for-each (lambda (x) (receive z (vv x) (list z))) (make-list 10000000 1))) | ; real 11.805 | ; user 11.750 | ; sys 0.040 | The point is that the 'call-with-values' version creates | a closure for every iteration, as well as mu version, while | 'receive' version can optimize it away. The same optimization | is done with srfi-11 let-values as well. | (If the optimizer is sufficienty smart, 'call-with-values' | version can also be compiled without creating closures, | given that the binding of 'call-with-values' itself is | not altered elsewhere.) | The difference of mu vs call-with-values did catch my | attention. There should be some room for improvement. Have you done the test in other implementations? -- Joo ChurlSoo