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comparison src/eval.c @ 2297:13a418960a88

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[xemacs-hg @ 2004-09-22 02:05:42 by stephent] various doc patches <87isa7awrh.fsf@tleepslib.sk.tsukuba.ac.jp>
author stephent
date Wed, 22 Sep 2004 02:06:52 +0000
parents 04bc9d2f42c7
children ecf1ebac70d8
comparison
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2296:a58ea4d0d0cd 2297:13a418960a88
1470 #endif /* ERROR_CHECK_TRAPPING_PROBLEMS */ 1470 #endif /* ERROR_CHECK_TRAPPING_PROBLEMS */
1471 1471
1472 DEFUN ("catch", Fcatch, 1, UNEVALLED, 0, /* 1472 DEFUN ("catch", Fcatch, 1, UNEVALLED, 0, /*
1473 \(catch TAG BODY...): eval BODY allowing nonlocal exits using `throw'. 1473 \(catch TAG BODY...): eval BODY allowing nonlocal exits using `throw'.
1474 TAG is evalled to get the tag to use. Then the BODY is executed. 1474 TAG is evalled to get the tag to use. Then the BODY is executed.
1475 Within BODY, (throw TAG) with same tag exits BODY and exits this `catch'. 1475 Within BODY, (throw TAG) with same (`eq') tag exits BODY and this `catch'.
1476 If no throw happens, `catch' returns the value of the last BODY form. 1476 If no throw happens, `catch' returns the value of the last BODY form.
1477 If a throw happens, it specifies the value to return from `catch'. 1477 If a throw happens, it specifies the value to return from `catch'.
1478 */ 1478 */
1479 (args)) 1479 (args))
1480 { 1480 {
1534 1534
1535 1535
1536 /* Unwind the specbind, catch, and handler stacks back to CATCH, and 1536 /* Unwind the specbind, catch, and handler stacks back to CATCH, and
1537 jump to that CATCH, returning VALUE as the value of that catch. 1537 jump to that CATCH, returning VALUE as the value of that catch.
1538 1538
1539 This is the guts Fthrow and Fsignal; they differ only in the way 1539 This is the guts of Fthrow and Fsignal; they differ only in the
1540 they choose the catch tag to throw to. A catch tag for a 1540 way they choose the catch tag to throw to. A catch tag for a
1541 condition-case form has a TAG of Qnil. 1541 condition-case form has a TAG of Qnil.
1542 1542
1543 Before each catch is discarded, unbind all special bindings and 1543 Before each catch is discarded, unbind all special bindings and
1544 execute all unwind-protect clauses made above that catch. Unwind 1544 execute all unwind-protect clauses made above that catch. Unwind
1545 the handler stack as we go, so that the proper handlers are in 1545 the handler stack as we go, so that the proper handlers are in
1707 condition_case_1). See below for more info. 1707 condition_case_1). See below for more info.
1708 */ 1708 */
1709 1709
1710 DEFUN_NORETURN ("throw", Fthrow, 2, 2, 0, /* 1710 DEFUN_NORETURN ("throw", Fthrow, 2, 2, 0, /*
1711 Throw to the catch for TAG and return VALUE from it. 1711 Throw to the catch for TAG and return VALUE from it.
1712 Both TAG and VALUE are evalled. 1712 Both TAG and VALUE are evalled. Tags are the same iff they are `eq'.
1713 */ 1713 */
1714 (tag, value)) 1714 (tag, value))
1715 { 1715 {
1716 throw_or_bomb_out (tag, value, 0, Qnil, Qnil); /* Doesn't return */ 1716 throw_or_bomb_out (tag, value, 0, Qnil, Qnil); /* Doesn't return */
1717 RETURN_NOT_REACHED (Qnil); 1717 RETURN_NOT_REACHED (Qnil);