26425: allow "emulate sh -c command" to eval command under sh emulation

3 files changed, 101 insertions, 25 deletions

diff --git a/ChangeLog b/ChangeLog
index d151dfbb2..bdd2da687 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2009-01-25  Andrey Borzenkov <bor@zsh.org>
+
+	* 26425: Doc/Zsh/builtins.yo Src/builtin.c:
+	"emulate csh -c command" will evaluate `command' after temporary
+	enable csh emulation. Note that `-c' is not actually an option,
+	but positional parameter.
+
 2009-01-24  Doug Kearns  <dougkearns@gmail.com>
 
 	* 26413: Completion/Unix/Command/_ant: update for version 1.7.1.
@@ -10995,5 +11002,5 @@
 
 *****************************************************
 * This is used by the shell to define $ZSH_PATCHLEVEL
-* $Revision: 1.4525 $                         
+* $Revision: 1.4526 $                         
 *****************************************************
diff --git a/Doc/Zsh/builtins.yo b/Doc/Zsh/builtins.yo
index d4d2a4c9c..6d1547de6 100644
--- a/Doc/Zsh/builtins.yo
+++ b/Doc/Zsh/builtins.yo
@@ -338,8 +338,11 @@ cindex(compatibility, csh)
 cindex(sh, compatibility)
 cindex(ksh, compatibility)
 cindex(csh, compatibility)
-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.
+item(tt(emulate) [ tt(-LR) ] [ {tt(zsh)|tt(sh)|tt(ksh)|tt(csh)} [ tt(-c) tt(arg) ] ])(
+Without any argument print current emulation mode.
+
+With single argument 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; more precisely, the tests performed on the
@@ -351,16 +354,21 @@ the section `Compatibility' in zmanref(zshmisc)
 ifnzman(\
 noderef(Compatibility)
 )\
-.  If the tt(-R) option is given, all options
+.
+
+If tt(-c) tt(arg) is given, evaluate tt(arg) after temporary setting
+requested emulation. Emulation will be restored before tt(emulate) returns.
+
+If the tt(-R) option is given, all options
 are reset to their default value corresponding to the specified emulation
 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 options tt(LOCAL_OPTIONS) and tt(LOCAL_TRAPS) will be set as
+problems in scripts and functions are altered.  If the tt(-L) option is given,
+the options tt(LOCAL_OPTIONS) and tt(LOCAL_TRAPS) will be set as
 well, causing the effects of the tt(emulate) command and any tt(setopt) and
 tt(trap) commands to be local to the immediately surrounding shell
 function, if any; normally these options are turned off in all emulation
-modes except tt(ksh).
+modes except tt(ksh). The tt(-L) and tt(-c) are mutually exclusive.
 )
 findex(enable)
 cindex(enabling commands)
diff --git a/Src/builtin.c b/Src/builtin.c
index 72c519037..99af38e3a 100644
--- a/Src/builtin.c
+++ b/Src/builtin.c
@@ -58,7 +58,7 @@ static struct builtin builtins[] =
     BUILTIN("disable", 0, bin_enable, 0, -1, BIN_DISABLE, "afmrs", NULL),
     BUILTIN("disown", 0, bin_fg, 0, -1, BIN_DISOWN, NULL, NULL),
     BUILTIN("echo", BINF_SKIPINVALID, bin_print, 0, -1, BIN_ECHO, "neE", "-"),
-    BUILTIN("emulate", 0, bin_emulate, 1, 1, 0, "LR", NULL),
+    BUILTIN("emulate", 0, bin_emulate, 0, 3, 0, "LR", NULL),
     BUILTIN("enable", 0, bin_enable, 0, -1, BIN_ENABLE, "afmrs", 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),
@@ -4744,24 +4744,12 @@ bin_dot(char *name, char **argv, UNUSED(Options ops), UNUSED(int func))
     return ret ? ret : lastval;
 }
 
-/**/
-int
-bin_emulate(UNUSED(char *nam), char **argv, Options ops, UNUSED(int func))
-{
-    emulate(*argv, OPT_ISSET(ops,'R'));
-    if (OPT_ISSET(ops,'L'))
-	opts[LOCALOPTIONS] = opts[LOCALTRAPS] = 1;
-    return 0;
-}
-
-/* eval: simple evaluation */
-
-/**/
-mod_export int ineval;
+/*
+ * common for bin_emulate and bin_eval
+ */
 
-/**/
-int
-bin_eval(UNUSED(char *nam), char **argv, UNUSED(Options ops), UNUSED(int func))
+static int
+eval(char **argv)
 {
     Eprog prog;
     char *oscriptname = scriptname;
@@ -4838,6 +4826,79 @@ bin_eval(UNUSED(char *nam), char **argv, UNUSED(Options ops), UNUSED(int func))
     return lastval;
 }
 
+/* emulate: set emulation mode and optionally evaluate shell code */
+
+/**/
+int
+bin_emulate(UNUSED(char *nam), char **argv, Options ops, UNUSED(int func))
+{
+    int opt_L = OPT_ISSET(ops, 'L');
+    int opt_R = OPT_ISSET(ops, 'R');
+    int saveemulation ;
+    int ret;
+    char saveopts[OPT_SIZE];
+
+    /* without arguments just print current emulation */
+    if (!*argv) {
+	if (opt_L || opt_R) {
+	    zwarnnam("emulate", "not enough arguments");
+	    return 1;
+	}
+
+	printf("%s\n", emulation == EMULATE_CSH ? "csh" :
+		       emulation == EMULATE_KSH ? "ksh" :
+		       emulation == EMULATE_SH  ? "sh" :
+		       "zsh");
+	return 0;
+    }
+
+    /* with single argument set current emulation */
+    if (!argv[1]) {
+	emulate(*argv, OPT_ISSET(ops,'R'));
+	if (OPT_ISSET(ops,'L'))
+	    opts[LOCALOPTIONS] = opts[LOCALTRAPS] = 1;
+	return 0;
+    }
+
+    /* If "-c command" is given, evaluate command using specified
+     * emulation mode.
+     */
+    if (strcmp(argv[1], "-c")) {
+	zwarnnam("emulate", "unknown argument %s", argv[1]);
+	return 1;
+    }
+
+    if (!argv[2]) {
+	zwarnnam("emulate", "not enough arguments");
+	return 1;
+    }
+
+    if (opt_L) {
+	zwarnnam("emulate", "option -L incompatible with -c");
+	return 1;
+    }
+
+    memcpy(saveopts, opts, sizeof(opts));
+    saveemulation = emulation;
+    emulate(*argv, OPT_ISSET(ops,'R'));
+    ret = eval(argv+2);
+    memcpy(opts, saveopts, sizeof(opts));
+    emulation = saveemulation;
+    return ret;
+}
+
+/* eval: simple evaluation */
+
+/**/
+mod_export int ineval;
+
+/**/
+int
+bin_eval(UNUSED(char *nam), char **argv, UNUSED(Options ops), UNUSED(int func))
+{
+    return eval(argv);
+}
+
 static char *zbuf;
 static int readfd;