From a18b70875fbcf22009e64bc9d809d1575fba3429 Mon Sep 17 00:00:00 2001 From: Noam Postavsky Date: Thu, 9 Aug 2018 21:26:30 -0400 Subject: [PATCH] Allow t as a catch-all condition-case handler (Bug#24618) * src/eval.c (find_handler_clause): Accept a handler of t as always matching. (Fcondition_case): * doc/lispref/control.texi (Handling Errors): Document this. * etc/NEWS: Announce it. --- doc/lispref/control.texi | 7 ++++--- etc/NEWS | 3 +++ src/eval.c | 10 ++++++---- 3 files changed, 13 insertions(+), 7 deletions(-) diff --git a/doc/lispref/control.texi b/doc/lispref/control.texi index 975ab3d075..8a6cf73af5 100644 --- a/doc/lispref/control.texi +++ b/doc/lispref/control.texi @@ -1878,9 +1878,10 @@ Handling Errors Each of the @var{handlers} is a list of the form @code{(@var{conditions} @var{body}@dots{})}. Here @var{conditions} is an error condition name to be handled, or a list of condition names (which can include @code{debug} -to allow the debugger to run before the handler); @var{body} is one or more -Lisp expressions to be executed when this handler handles an error. -Here are examples of handlers: +to allow the debugger to run before the handler). A condition name of +@code{t} matches any condition. @var{body} is one or more Lisp +expressions to be executed when this handler handles an error. Here +are examples of handlers: @example @group diff --git a/etc/NEWS b/etc/NEWS index 8abbd74e05..f7de6c7295 100644 --- a/etc/NEWS +++ b/etc/NEWS @@ -836,6 +836,9 @@ specially; they are now allocated like any other pseudovector. * Lisp Changes in Emacs 27.1 +++ +** 'condition-case' now accepts 't' to match any error symbol. + ++++ ** New function 'proper-list-p'. Given a proper list as argument, this predicate returns its length; otherwise, it returns nil. 'format-proper-list-p' is now an obsolete diff --git a/src/eval.c b/src/eval.c index 8745ba9ef9..8700f0e202 100644 --- a/src/eval.c +++ b/src/eval.c @@ -1215,9 +1215,9 @@ DEFUN ("condition-case", Fcondition_case, Scondition_case, 2, UNEVALLED, 0, Each element of HANDLERS looks like (CONDITION-NAME BODY...) where the BODY is made of Lisp expressions. -A handler is applicable to an error -if CONDITION-NAME is one of the error's condition names. -If an error happens, the first applicable handler is run. +A handler is applicable to an error if CONDITION-NAME is one of the +error's condition names. A CONDITION-NAME of t applies to any error +symbol. If an error happens, the first applicable handler is run. The car of a handler may be a list of condition names instead of a single condition name; then it handles all of them. If the special @@ -1854,7 +1854,9 @@ find_handler_clause (Lisp_Object handlers, Lisp_Object conditions) for (h = handlers; CONSP (h); h = XCDR (h)) { Lisp_Object handler = XCAR (h); - if (!NILP (Fmemq (handler, conditions))) + if (!NILP (Fmemq (handler, conditions)) + /* t is also used as a catch-all by Lisp code. */ + || EQ (handler, Qt)) return handlers; } -- 2.11.0