On Saturday 29 November 2008 07:29, Randall R Schulz wrote: > On Saturday 29 November 2008 06:55, Randall R Schulz wrote: > > ... > > > > It's a good technique, though, to see what the compiler is going to > > be asked to translate after all players between the form as > > submitted and the compiler have done their thing. > > Or is it? > > ... I'm working my way through Stuart H.'s book. > I'm on the sequence section (4.2) and just got to "for". > Here's what I did / found: > > ... > > So seeing that "for" is a macro, I thought I'd see what it produces. > I started with the example included in the doc string: > > user=> (macroexpand '(take 100 (for [x (range 100000000) y (range > 1000000) :while (< y x)] [x y]))) (take 100 (for [x (range 100000000) > y (range 1000000) :while (< y x)] [x y])) > > > So next I tried macroexpand -ing just the (for ...) sub-form: > > user=> (macroexpand '(for [x (range 100000000) y (range 1000000) > :while (< y x)] [x y])) (let* [iter__3869 (clojure.core/fn iter__33 > [s__34] (clojure.core/when-first [x s__34] (if true > ... > > > I'm somewhat confused by this, but I gather it has something to do > with "take" being lazy?
And, continuing my exploration, the confirmation of this hunch comes shortly after, in section 4.3. This does, at least, impose a caveat on the use of macroexpand as a tool for understanding what your code really says (and does). Randall Schulz --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
