--- orig/libguile/ChangeLog +++ mod/libguile/ChangeLog @@ -1,3 +1,9 @@ +2007-05-26 Ludovic Courtès + + * eval.c (scm_m_define): Updated comment. Changed order for value + evaluation and `scm_sym2var ()' call, which is perfectly valid per + R5RS. This reverts the change dated 2004-04-22 by Dirk Herrmann. + 2007-05-05 Ludovic Courtès Implemented lazy duplicate binding handling. --- orig/libguile/eval.c +++ mod/libguile/eval.c @@ -1209,10 +1209,11 @@ return expr; } -/* According to section 5.2.1 of R5RS we first have to make sure that the - * variable is bound, and then perform the (set! variable expression) - * operation. This means, that within the expression we may already assign - * values to variable: (define foo (begin (set! foo 1) (+ foo 1))) */ +/* According to Section 5.2.1 of R5RS we first have to make sure that the + variable is bound, and then perform the `(set! variable expression)' + operation. However, EXPRESSION _can_ be evaluated before VARIABLE is + bound. This means that EXPRESSION won't necessarily be able to assign + values to VARIABLE as in `(define foo (begin (set! foo 1) (+ foo 1)))'. */ SCM scm_m_define (SCM expr, SCM env) { @@ -1222,9 +1223,9 @@ const SCM canonical_definition = canonicalize_define (expr); const SCM cdr_canonical_definition = SCM_CDR (canonical_definition); const SCM variable = SCM_CAR (cdr_canonical_definition); + const SCM value = scm_eval_car (SCM_CDR (cdr_canonical_definition), env); const SCM location = scm_sym2var (variable, scm_env_top_level (env), SCM_BOOL_T); - const SCM value = scm_eval_car (SCM_CDR (cdr_canonical_definition), env); if (SCM_REC_PROCNAMES_P) { --- orig/test-suite/ChangeLog +++ mod/test-suite/ChangeLog @@ -1,3 +1,11 @@ +2007-05-26 Ludovic Courtès + + * tests/syntax.test (top-level define)[binding is created before + expression is evaluated]: Moved to "internal define", using `let' + instead of `begin'. The test was not necessarily valid for + top-level defines, according to Section 5.2.1 or R5RS. + [redefinition]: New. + 2007-05-09 Ludovic Courtès * tests/srfi-19.test ((current-time time-tai) works): Use `time?'. --- orig/test-suite/tests/syntax.test +++ mod/test-suite/tests/syntax.test @@ -725,15 +725,16 @@ (with-test-prefix "top-level define" - (pass-if "binding is created before expression is evaluated" - (= (eval '(begin - (define foo - (begin - (set! foo 1) - (+ foo 1))) - foo) - (interaction-environment)) - 2)) + (pass-if "redefinition" + (let ((m (make-module))) + (beautify-user-module! m) + + ;; The previous value of `round' must still be visible at the time the + ;; new `round' is defined. According to R5RS (Section 5.2.1), `define' + ;; should behave like `set!' in this case (except that in the case of + ;; Guile, we respect module boundaries). + (eval '(define round round) m) + (eq? (module-ref m 'round) round))) (with-test-prefix "currying" @@ -780,6 +781,17 @@ (eq? 'c (a 2) (a 5)))) (interaction-environment))) + (pass-if "binding is created before expression is evaluated" + ;; Internal defines are equivalent to `letrec' (R5RS, Section 5.2.2). + (= (eval '(let () + (define foo + (begin + (set! foo 1) + (+ foo 1))) + foo) + (interaction-environment)) + 2)) + (pass-if "internal defines with begin" (false-if-exception (eval '(let ((a identity) (b identity) (c identity))