At Wed, 6 Aug 2014 22:03:17 +0200, Jens Axel Søgaard wrote: > The program below produce bytecodes for the program that returns a > syntax-object representing 42. > > The syntax-object looks like this: > > (#s((stx zo 0) > #s((wrapped zo 0) > 42 > (#s((top-level-rename wrap 0 zo 0) #f) > #s((top-level-rename wrap 0 zo 0) #f) > #s((top-level-rename wrap 0 zo 0) #t) > #s((phase-shift wrap 0 zo 0) 0 #f #f #f)) > clean)))) > > Two questions: > 1) Why three top-level-renames and not just one? > > 2) What is the meaning of the boolean flag?
The boolean apparently indicates whether the rename is for phase 0. It should instead be the phase of the rename, where using a boolean for the phase is probably a leftover from an original implementation where imports were either phase 0 or phase 1. The three renames are from phases 0, 1, and #f. I think this mismatch has gone unnoticed because we generally don't try to use non-module code in bytecode form --- especially non-module code that would involve syntax objects. > #lang racket > (require compiler/zo-structs compiler/zo-parse) > > (define (bytecode->zo bytecode) > (zo-parse > (open-input-bytes > (with-output-to-bytes > (λ () (write bytecode)))))) > > (define (stx->zo x) > (parameterize ([current-namespace (make-base-empty-namespace)]) > (namespace-require 'racket/base) > (bytecode->zo (compile x)))) > > (stx->zo '(syntax 42)) > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
