PATCH: zsh-3.1.5-pws-7: emulate locally

[Peter Stephenson <pws@ibmth.df.unipi.it>]

When using `emulate' in a shell function to ensure the correct
environment, it's a good habit to make sure the effect is local by
setting localoptions.  To encourage this good habit, I thought perhaps
it might be sensible to have an option -L to emulate itself to do
this.  Certainly you can just add `setopt localoptions', but it's easy
to forget.  If you always use `emulate -LR zsh', then you don't
forget.  I tried to clarify the manual entry a bit.
 
--- Doc/Zsh/builtins.yo.emloc	Thu Feb  4 17:50:30 1999
+++ Doc/Zsh/builtins.yo	Wed Feb 10 17:51:56 1999
@@ -215,13 +215,19 @@
 cindex(sh, compatibility)
 cindex(ksh, compatibility)
 cindex(csh, compatibility)
-item(tt(emulate) [ tt(-R) ] {tt(zsh)|tt(sh)|tt(ksh)|tt(csh)})(
+item(tt(emulate) [ tt(-LR) ] {tt(zsh)|tt(sh)|tt(ksh)|tt(csh)})(
 Set up zsh options to emulate the specified shell as much as possible.
 bf(csh) will never be fully emulated.
 If the argument is not one of the shells listed above, tt(zsh)
 will be used as a default.  If the tt(-R) option is given, all options
 are reset to their default value corresponding to the specified emulation
-mode.
+mode, except for certain options describing the interactive
+environment; otherwise, only those options likely to cause portability
+problems in scripts and functions are altered.  If the tt(-L) option
+is given, the option tt(LOCAL_OPTIONS) will be set as well, causing
+the effect of the tt(emulate) command to be local to the immediately
+surrounding shell function, if any; normally this is turned off in all
+emulation modes except tt(ksh).
 )
 findex(enable)
 cindex(enabling commands)
--- Src/builtin.c.emloc	Mon Feb  8 09:59:10 1999
+++ Src/builtin.c	Wed Feb 10 17:35:28 1999
@@ -56,7 +56,7 @@
     BUILTIN("disown", 0, bin_fg, 0, -1, BIN_DISOWN, NULL, NULL),
     BUILTIN("echo", BINF_PRINTOPTS | BINF_ECHOPTS, bin_print, 0, -1, BIN_ECHO, "neE", "-"),
     BUILTIN("echotc", 0, bin_echotc, 1, -1, 0, NULL, NULL),
-    BUILTIN("emulate", 0, bin_emulate, 1, 1, 0, "R", NULL),
+    BUILTIN("emulate", 0, bin_emulate, 1, 1, 0, "LR", NULL),
     BUILTIN("enable", 0, bin_enable, 0, -1, BIN_ENABLE, "afmr", NULL),
     BUILTIN("eval", BINF_PSPECIAL, bin_eval, 0, -1, BIN_EVAL, NULL, NULL),
     BUILTIN("exit", BINF_PSPECIAL, bin_break, 0, 1, BIN_EXIT, NULL, NULL),
@@ -3051,6 +3051,8 @@
 bin_emulate(char *nam, char **argv, char *ops, int func)
 {
     emulate(*argv, ops['R']);
+    if (ops['L'])
+	dosetopt(LOCALOPTIONS, 1, 0);
     return 0;
 }
 
-- 
Peter Stephenson <pws@ibmth.df.unipi.it>       Tel: +39 050 844536
WWW:  http://www.ifh.de/~pws/
Dipartimento di Fisica, Via Buonarroti 2, 56127 Pisa, Italy