diff options
Diffstat (limited to 'libguile/dynwind.c')
-rw-r--r-- | libguile/dynwind.c | 54 |
1 files changed, 30 insertions, 24 deletions
diff --git a/libguile/dynwind.c b/libguile/dynwind.c index 101107c70..c79097b61 100644 --- a/libguile/dynwind.c +++ b/libguile/dynwind.c @@ -70,60 +70,66 @@ SCM_DEFINE (scm_dynamic_wind, "dynamic-wind", 3, 0, 0, - (SCM thunk1, SCM thunk2, SCM thunk3), - "All three arguments must be 0-argument procedures.\n\n" - "@var{in-guard} is called, then @var{thunk}, then @var{out-guard}.\n\n" - "If, any time during the execution of @var{thunk}, the continuation\n" - "of the @code{dynamic-wind} expression is escaped non-locally, @var{out-guard}\n" - "is called. If the continuation of the dynamic-wind is re-entered,\n" - "@var{in-guard} is called. Thus @var{in-guard} and @var{out-guard} may\n" - "be called any number of times.\n\n" - "@example\n" + (SCM in_guard, SCM thunk, SCM out_guard), + "All three arguments must be 0-argument procedures.\n" + "@var{in_guard} is called, then @var{thunk}, then\n" + "@var{out_guard}.\n" + "\n" + "If, any time during the execution of @var{thunk}, the\n" + "continuation of the @code{dynamic_wind} expression is escaped\n" + "non-locally, @var{out_guard} is called. If the continuation of\n" + "the dynamic-wind is re-entered, @var{in_guard} is called. Thus\n" + "@var{in_guard} and @var{out_guard} may be called any number of\n" + "times.\n" + "@lisp\n" "(define x 'normal-binding)\n" - "@result{} x\n\n" + "@result{} x\n" "(define a-cont (call-with-current-continuation \n" " (lambda (escape)\n" " (let ((old-x x))\n" " (dynamic-wind\n" " ;; in-guard:\n" " ;;\n" - " (lambda () (set! x 'special-binding))\n\n" + " (lambda () (set! x 'special-binding))\n" + "\n" " ;; thunk\n" " ;;\n" " (lambda () (display x) (newline)\n" " (call-with-current-continuation escape)\n" " (display x) (newline)\n" - " x)\n\n" + " x)\n" + "\n" " ;; out-guard:\n" " ;;\n" - " (lambda () (set! x old-x)))))))\n\n" + " (lambda () (set! x old-x)))))))\n" + "\n" ";; Prints: \n" "special-binding\n" ";; Evaluates to:\n" - "@result{} a-cont\n\n" + "@result{} a-cont\n" "x\n" - "@result{} normal-binding\n\n" + "@result{} normal-binding\n" "(a-cont #f)\n" ";; Prints:\n" "special-binding\n" ";; Evaluates to:\n" - "@result{} a-cont ;; the value of the (define a-cont...)\n\n" + "@result{} a-cont ;; the value of the (define a-cont...)\n" "x\n" - "@result{} normal-binding\n\n" + "@result{} normal-binding\n" "a-cont\n" "@result{} special-binding\n" - "@end example\n") + "@end lisp") #define FUNC_NAME s_scm_dynamic_wind { SCM ans; - SCM_ASSERT (SCM_NFALSEP (scm_thunk_p (thunk3)), - thunk3, + SCM_ASSERT (SCM_NFALSEP (scm_thunk_p (out_guard)), + out_guard, SCM_ARG3, FUNC_NAME); - scm_apply (thunk1, SCM_EOL, SCM_EOL); - scm_dynwinds = scm_acons (thunk1, thunk3, scm_dynwinds); - ans = scm_apply (thunk2, SCM_EOL, SCM_EOL); + scm_apply (in_guard, SCM_EOL, SCM_EOL); + scm_dynwinds = scm_acons (in_guard, out_guard, scm_dynwinds); + ans = scm_apply (thunk, SCM_EOL, SCM_EOL); scm_dynwinds = SCM_CDR (scm_dynwinds); - scm_apply (thunk3, SCM_EOL, SCM_EOL); + scm_apply (out_guard, SCM_EOL, SCM_EOL); return ans; } #undef FUNC_NAME |