PATCH: 3.1.5-pws-8: magicequalsubst

[Peter Stephenson <pws@xxxxxxxxxxxxxxxxx>]

Here's the proposed patch simplifying the behaviour of the magicequalsubst
option.  I had no messages objecting, and two saying `why wasn't it like
that before', so I suppose that's positive.

I also took the opportunity of replacing the flags passed to and by
prefork() by macros for readability.

--- Doc/Zsh/options.yo.fsub	Fri Feb  5 10:16:00 1999
+++ Doc/Zsh/options.yo	Mon Feb 15 18:25:21 1999
@@ -544,12 +544,14 @@
 )
 pindex(MAGIC_EQUAL_SUBST)
 item(tt(MAGIC_EQUAL_SUBST))(
-All unquoted arguments of the form `var(identifier)tt(=)var(expression)'
+All unquoted arguments of the form `var(anything)tt(=)var(expression)'
 appearing after the command name have filename expansion (that is,
 where var(expression) has a leading `tt(~)' or `tt(=)') performed on
 var(expression) as if it were a parameter assignment.  The argument is
 not otherwise treated specially; it is passed to the command as a single
-argument, and not used as an actual parameter assignment.
+argument, and not used as an actual parameter assignment.  For example, in
+tt(echo foo=~/bar:~/rod), both occurrences of tt(~) would be replaced.
+Note that this happens anyway with tt(typeset) and similar statements.
 )
 pindex(MAIL_WARNING)
 cindex(mail, warning of reading)
--- Src/exec.c.fsub	Mon Feb  1 09:42:00 1999
+++ Src/exec.c	Mon Feb 15 18:10:51 1999
@@ -1208,7 +1208,7 @@
 	    addlinknode(vl, v->str);
 	} else
 	    vl = v->arr;
-	prefork(vl, v->type == PM_SCALAR ? 7 : 3);
+	prefork(vl, v->type == PM_SCALAR ? (PF_SINGLE|PF_ASSIGN) : PF_ASSIGN);
 	if (errflag)
 	    return;
 	if (isset(GLOBASSIGN) || v->type != PM_SCALAR)
@@ -1356,7 +1356,7 @@
     }
 
     /* Do prefork substitutions */
-    prefork(args, assign ? 2 : isset(MAGICEQUALSUBST));
+    prefork(args, (assign || isset(MAGICEQUALSUBST)) ? PF_TYPESET : 0);
 
     if (type == SIMPLE) {
 	int unglobbed = 0;
--- Src/glob.c.fsub	Wed Feb  3 12:14:49 1999
+++ Src/glob.c	Mon Feb 15 18:10:51 1999
@@ -1810,7 +1810,7 @@
     fake = newlinklist();
     addlinknode(fake, fn->name);
     /* ...which undergoes all the usual shell expansions */
-    prefork(fake, isset(MULTIOS) ? 0 : 4);
+    prefork(fake, isset(MULTIOS) ? 0 : PF_SINGLE);
     /* Globbing is only done for multios. */
     if (!errflag && isset(MULTIOS))
 	globlist(fake);
--- Src/subst.c.fsub	Fri Feb  5 10:08:47 1999
+++ Src/subst.c	Mon Feb 15 18:15:20 1999
@@ -42,11 +42,7 @@
  *  - Brace expansion
  *  - Tilde and equals substitution
  *
- * Bits 0 and 1 of flags are used in filesub.
- * bit 0 is set when we are doing MAGIC_EQUALSUBST or normal
- *	 assignment but not a typeset.
- * bit 1 is set on a real assignment (both typeset and normal).
- * bit 2 is a flag to paramsubst (single word sub)
+ * PF_* flags are defined in zsh.h
  */
 
 /**/
@@ -70,20 +66,22 @@
 		return;
 	} else {
 	    if (isset(SHFILEEXPANSION))
-		filesub((char **)getaddrdata(node), flags & 3);
-	    if (!(node = stringsubst(list, node, flags & 4)))
+		filesub((char **)getaddrdata(node),
+			flags & (PF_TYPESET|PF_ASSIGN));
+	    if (!(node = stringsubst(list, node, flags & PF_SINGLE)))
 		return;
 	}
     }
     for (node = firstnode(list); node; incnode(node)) {
 	if (*(char *)getdata(node)) {
 	    remnulargs(getdata(node));
-	    if (unset(IGNOREBRACES) && !(flags & 4))
+	    if (unset(IGNOREBRACES) && !(flags & PF_SINGLE))
 		while (hasbraces(getdata(node)))
 		    xpandbraces(list, &node);
 	    if (unset(SHFILEEXPANSION))
-		filesub((char **)getaddrdata(node), flags & 3);
-	} else if (!(flags & 4))
+		filesub((char **)getaddrdata(node),
+			flags & (PF_TYPESET|PF_ASSIGN));
+	} else if (!(flags & PF_SINGLE))
 	    uremnode(list, node);
 	if (errflag)
 	    return;
@@ -234,7 +232,7 @@
 
     foo = newlinklist();
     addlinknode(foo, *s);
-    prefork(foo, 4);
+    prefork(foo, PF_SINGLE);
     if (errflag)
 	return;
     *s = (char *) ugetnode(foo);
@@ -287,8 +285,10 @@
     return !l;
 }
 
-/* ~, = subs: assign = 2 => typeset; assign = 1 => something that looks
-	like an assignment but may not be; assign = 3 => normal assignment */
+/*
+ * ~, = subs: assign & PF_TYPESET => typeset or magic equals
+ *            assign & PF_ASSIGN => normal assignment
+ */
 
 /**/
 void
@@ -302,12 +302,8 @@
     if (!assign)
 	return;
 
-    if (assign < 3) {
+    if (assign & PF_TYPESET) {
 	if ((*namptr)[1] && (sub = strchr(*namptr + 1, Equals))) {
-	    if (assign == 1)
-		for (ptr = *namptr; ptr != sub; ptr++)
-		    if (!iident(*ptr) && !INULL(*ptr))
-			return;
 	    str = sub + 1;
 	    if ((sub[1] == Tilde || sub[1] == Equals) && filesubstr(&str, assign)) {
 		sub[1] = '\0';
--- Src/zsh.h.fsub	Sat Feb 13 14:14:24 1999
+++ Src/zsh.h	Tue Feb 16 10:15:51 1999
@@ -950,6 +950,11 @@
 #define SUB_ALL		0x0100	/* match complete string */
 #define SUB_GLOBAL	0x0200	/* global substitution ${..//all/these} */
 
+/* Flags as the second argument to prefork */
+#define PF_TYPESET	0x01	/* argument handled like typeset foo=bar */
+#define PF_ASSIGN	0x02	/* argument handled like the RHS of foo=bar */
+#define PF_SINGLE	0x04	/* single word substitution */
+
 /* node for named directory hash table (nameddirtab) */
 
 struct nameddir {

-- 
Peter Stephenson <pws@xxxxxxxxxxxxxxxxx>       Tel: +39 050 844536
WWW:  http://www.ifh.de/~pws/
Dipartimento di Fisica, Via Buonarroti 2, 56127 Pisa, Italy