From: Jonathan Yavner <jyavner@member.fsf.org>
Date: Sun, 30 Nov 2003 06:56:59 +0000 (+0000)
Subject: Add macros `1value' and `noreturn'.
X-Git-Tag: ttn-vms-21-2-B4~8243
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=1116910a519ba0e4ff84b9a83ff5207aa4fe5a24;p=emacs.git

Add macros `1value' and `noreturn'.
---

diff --git a/lisp/subr.el b/lisp/subr.el
index dba7331f98c..2996f2903e0 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -62,6 +62,20 @@ The return value of this function is not used."
 
 (defalias 'not 'null)
 
+(defmacro noreturn (form)
+  "Evaluates FORM, with the expectation that the evaluation will signal an error
+instead of returning to its caller.  If FORM does return, an error is
+signalled." 
+  `(prog1 ,form
+     (error "Form marked with `noreturn' did return")))
+
+(defmacro 1value (form)
+  "Evaluates FORM, with the expectation that all the same value will be returned
+from all evaluations of FORM.  This is the global do-nothing
+version of `1value'.  There is also `testcover-1value' that
+complains if FORM ever does return differing values."
+  form)
+
 (defmacro lambda (&rest cdr)
   "Return a lambda expression.
 A call of the form (lambda ARGS DOCSTRING INTERACTIVE BODY) is