Ah, okay, that makes sense. Thank you. I didn't realize begin was evaluating each expression as it went.
Thank you. ~Leif Andersen On Mon, Dec 21, 2015 at 5:47 PM, Matthew Flatt <mfl...@cs.utah.edu> wrote: > In the REPL, `begin` splices at the granularity of expansion and > evaluation. That is, the first of the two forms grouped by `begin` is > compiled and evaluated, and only afterward the second one is compiled > and evaluated. > > The `compile` function can't do that, because it's only supposed to > compile -- not evaluate. > > The `syntax/toplevel` library provides > > expand-syntax-top-level-with-compile-time-evals > > as an intermediate point between those: it pulls apart `begin` and > `expands` (which is the interesting part of `compile`) the forms in > sequence, but it evaluates only compile-time parts of the given forms. > That works for many cases, including your example. > > At Mon, 21 Dec 2015 17:35:22 -0700, Leif Andersen wrote: >> So, I was under the impression that the REPL was the toplevel (unless >> you entered a module context or something like that). But I just had >> something challenge that assumption and so now I'm a bit confused. >> >> I have the following top level program: >> >> (begin >> (require (for-meta 1 racket) >> (for-meta 2 racket)) >> (begin-for-syntax >> (begin-for-syntax >> (define x 5)))) >> >> When I run this top level program in the REPL, it works just fine. And >> I can even reference x in later evaluations. (Provided I'm at the >> meta-level of 2). >> >> However, when I pass this top level program into compile like so: >> http://pasterack.org/pastes/38556 >> >> (compile #'(begin >> (require (for-meta 1 racket) >> (for-meta 2 racket)) >> (begin-for-syntax >> (begin-for-syntax >> (define x 5))))) >> >> >> I get the following error: >> >> define: unbound identifier at phase 2; >> also, no #%app syntax transformer is bound in: define >> >> Can someone give me the reason (or at least some intuition) as to why >> this works in the repl, but not at the top level? >> >> Thank you. >> >> ~Leif Andersen >> >> -- >> 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 racket-users+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. > > -- > 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 racket-users+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. -- 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 racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
