Ahh ok, thank you that makes sense. I didn't know about PLT_LINKLET_SHOW_CP0 before that is a nice look behind the scene.
[email protected] schrieb am Sonntag, 21. März 2021 um 19:47:03 UTC+1: > That’s not the job of the macro expander. And the Racket optimizer does > reduce (if '#t (#%app not '#f) '#f) — in fact to #t. > > If you use Racket CS, try running: > > PLT_LINKLET_SHOW_CP0=1 racket file.rkt > > where file.rkt is > > #lang racket > (displayln (if #t (not #f) #f)) > > Here’s the optimized program: > > ;; cp0 --------------------- > (lambda (instance-variable-reference .get-syntax-literal!1 > .set-transformer!2 displayln3 print-values4) > (call-with-module-prompt > (lambda () > (#%call-with-values > (lambda () (displayln3 #t)) > print-values4))) > (#2%void)) > > > On Mon, Mar 22, 2021 at 1:28 AM [email protected] <[email protected]> > wrote: > >> The [WordCount] thread caused me to play around with the solutions to see >> whether I could see anything else that can be tweaked, I tried a few things >> but they didn't improve performance, but it was fun anyway. >> >> Then I though I could try the macro stepper and look at the expansion of >> [crowdsourced]. >> I disabled macro hiding and stepped to the end. >> There I saw if statements with a condition that is `(quote #t)` with a >> little lock symbol before it. >> >> I would like to understand why those terms aren't reduced further. >> Are they placeholders and are replaced and resolved at a later time? >> >> terms copied (without the lock symbol) from the macro stepper >> (if (if '#t (#%app not '#f) '#f) >> (#%app for-loop (#%app unsafe-fx+ '1 pos)) >> (#%app values)) >> >> From a naive standpoint I would expect it to be simplified: >> (if '#t (#%app not '#f) '#f) -> (#%app not '#f) >> >> (if (#%app not '#f) >> (#%app for-loop (#%app unsafe-fx+ '1 pos)) >> (#%app values)) >> >> So expressed another way: why isn't the if with boolean literal as >> condition reduced to the corresponding branch? Or does this happen, just >> isn't shown in the macro stepper? >> What am I misunderstanding here? >> >> If there aren't simplifications like that, what is preventing them or >> making them not worthwhile? >> >> >> [WordCount] >> https://groups.google.com/g/racket-users/c/lGA60P6jboY/m/2ZLDAunBBgAJ >> [crowdsourced] >> https://gist.github.com/Bogdanp/b9256e1a91de9083830cb616b3659ff8 >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Racket Users" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/racket-users/fce863fe-85d7-44a6-a2ba-5778df40e6bfn%40googlegroups.com >> >> <https://groups.google.com/d/msgid/racket-users/fce863fe-85d7-44a6-a2ba-5778df40e6bfn%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/cd4f9860-e57d-4ce2-bef8-6598a28ddfafn%40googlegroups.com.
