PATCH (redux): non-POSIX `for' syntax

[Peter Stephenson <pws@csr.com>]

"Bart Schaefer" wrote:
> This goes on top of the last one.

This is my patch relative to the foregoing.  It improves the documentation,
and adds the fix not to expand aliases in parameter names after the first.

Index: Doc/Zsh/grammar.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/grammar.yo,v
retrieving revision 1.4
diff -u -r1.4 grammar.yo
--- Doc/Zsh/grammar.yo	2000/08/29 06:35:40	1.4
+++ Doc/Zsh/grammar.yo	2001/06/21 15:27:31
@@ -149,12 +149,21 @@
 findex(for)
 cindex(for loops)
 cindex(loops, for)
-item(tt(for) var(name) [ tt(in) var(word) ... var(term) ] tt(do) var(list) tt(done))(
+item(tt(for) var(name) ... [ tt(in) var(word) ... ] var(term) tt(do) var(list) tt(done))(
 where var(term) is at least one newline or tt(;).
 Expand the list of var(word)s, and set the parameter
 var(name) to each of them in turn, executing
 var(list) each time.  If the tt(in) var(word) is omitted,
 use the positional parameters instead of the var(word)s.
+
+More than one parameter var(name) can appear before the list of
+var(word)s.  If var(N) var(name)s are given, then on each execution of the
+loop the next tt(N) var(word)s are assigned to the corresponding
+parameters.  If there are more var(name)s than remaining var(word)s, the
+remaining parameters are each set to the empty string.  Execution of the
+loop ends when there is no remaining var(word) to assign to the first
+var(name).  It is only possible for tt(in) to appear as the first var(name)
+in the list, else it will be treated as marking the end of the list.
 )
 item(tt(for LPAR()LPAR()) [var(expr1)] tt(;) [var(expr2)] tt(;) [var(expr3)] tt(RPAR()RPAR() do) var(list) tt(done))(
 The arithmetic expression var(expr1) is evaluated first (see
@@ -289,17 +298,17 @@
 item(tt(if) var(list) var(sublist))(
 A short form of the alternate `if'.
 )
-item(tt(for) var(name) tt(LPAR()) var(word) ... tt(RPAR()) var(sublist))(
+item(tt(for) var(name) ... tt(LPAR()) var(word) ... tt(RPAR()) var(sublist))(
 A short form of tt(for).
 )
-item(tt(for) var(name) [ tt(in) var(word) ... var(term) ] var(sublist))(
+item(tt(for) var(name) ... [ tt(in) var(word) ... ] var(term) var(sublist))(
 where var(term) is at least one newline or tt(;).
 Another short form of tt(for).
 )
 item(tt(for LPAR()LPAR()) [var(expr1)] tt(;) [var(expr2)] tt(;) [var(expr3)] tt(RPAR()RPAR()) var(sublist))(
 A short form of the arithmetic tt(for) command.
 )
-item(tt(foreach) var(name) tt(LPAR()) var(word) ... tt(RPAR()) var(list) tt(end))(
+item(tt(foreach) var(name) ... tt(LPAR()) var(word) ... tt(RPAR()) var(list) tt(end))(
 Another form of tt(for).
 )
 item(tt(while) var(list) tt({) var(list) tt(}))(
Index: Src/loop.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/loop.c,v
retrieving revision 1.4
diff -u -r1.4 loop.c
--- Src/loop.c	2000/06/17 17:05:53	1.4
+++ Src/loop.c	2001/06/21 15:27:31
@@ -52,15 +52,15 @@
     Wordcode end, loop;
     wordcode code = state->pc[-1];
     int iscond = (WC_FOR_TYPE(code) == WC_FOR_COND), ctok = 0, atok = 0;
+    int last = 0;
     char *name, *str, *cond = NULL, *advance = NULL;
     zlong val = 0;
-    LinkList args = NULL;
+    LinkList vars = NULL, args = NULL;
 
-    name = ecgetstr(state, EC_NODUP, NULL);
     end = state->pc + WC_FOR_SKIP(code);
 
     if (iscond) {
-	str = dupstring(name);
+	str = dupstring(ecgetstr(state, EC_NODUP, NULL));
 	singsub(&str);
 	if (isset(XTRACE)) {
 	    char *str2 = dupstring(str);
@@ -77,28 +77,32 @@
 	}
 	cond = ecgetstr(state, EC_NODUP, &ctok);
 	advance = ecgetstr(state, EC_NODUP, &atok);
-    } else if (WC_FOR_TYPE(code) == WC_FOR_LIST) {
-	int htok = 0;
-
-	if (!(args = ecgetlist(state, *state->pc++, EC_DUPTOK, &htok))) {
-	    state->pc = end;
-	    return 0;
-	}
-	if (htok)
-	    execsubst(args);
     } else {
-	char **x;
+	vars = ecgetlist(state, *state->pc++, EC_NODUP, NULL);
+
+	if (WC_FOR_TYPE(code) == WC_FOR_LIST) {
+	    int htok = 0;
+
+	    if (!(args = ecgetlist(state, *state->pc++, EC_DUPTOK, &htok))) {
+		state->pc = end;
+		return 0;
+	    }
+	    if (htok)
+		execsubst(args);
+	} else {
+	    char **x;
 
-	args = newlinklist();
-	for (x = pparams; *x; x++)
-	    addlinknode(args, dupstring(*x));
+	    args = newlinklist();
+	    for (x = pparams; *x; x++)
+		addlinknode(args, dupstring(*x));
+	}
     }
     lastval = 0;
     loops++;
     pushheap();
     cmdpush(CS_FOR);
     loop = state->pc;
-    for (;;) {
+    while (!last) {
 	if (iscond) {
 	    if (ctok) {
 		str = dupstring(cond);
@@ -127,14 +131,29 @@
 	    if (!val)
 		break;
 	} else {
-	    if (!args || !(str = (char *) ugetnode(args)))
-		break;
-	    if (isset(XTRACE)) {
-		printprompt4();
-		fprintf(xtrerr, "%s=%s\n", name, str);
-		fflush(xtrerr);
+	    LinkNode node;
+	    int count = 0;
+	    for (node = firstnode(vars); node; incnode(node))
+	    {
+		name = (char *)getdata(node);
+		if (!args || !(str = (char *) ugetnode(args)))
+		{
+		    if (count) { 
+			str = "";
+			last = 1;
+		    } else
+			break;
+		}
+		if (isset(XTRACE)) {
+		    printprompt4();
+		    fprintf(xtrerr, "%s=%s\n", name, str);
+		    fflush(xtrerr);
+		}
+		setsparam(name, ztrdup(str));
+		count++;
 	    }
-	    setsparam(name, ztrdup(str));
+	    if (!count)
+		break;
 	}
 	state->pc = loop;
 	execlist(state, 1, do_exec && args && empty(args));
Index: Src/parse.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/parse.c,v
retrieving revision 1.25
diff -u -r1.25 parse.c
--- Src/parse.c	2001/06/21 10:54:49	1.25
+++ Src/parse.c	2001/06/21 15:27:31
@@ -878,7 +878,7 @@
 par_for(int *complex)
 {
     int oecused = ecused, csh = (tok == FOREACH), p, sel = (tok == SELECT);
-    int type;
+    int type, ona = noaliases;
 
     p = ecadd(0);
 
@@ -903,19 +903,32 @@
 	yylex();
 	type = WC_FOR_COND;
     } else {
-	int posix_in;
+	int np, n, posix_in;
 	infor = 0;
 	if (tok != STRING || !isident(tokstr))
 	    YYERRORV(oecused);
-	ecstr(tokstr);
+	np = ecadd(0);
+	n = 0;
 	incmdpos = 1;
-	yylex();
+	noaliases = 1;
+	for (;;) {
+	    n++;
+	    ecstr(tokstr);
+	    yylex();	
+	    if (tok != STRING || !strcmp(tokstr, "in") || sel)
+		break;
+	    if (!isident(tokstr))
+	    {
+		noaliases = ona;
+		YYERRORV(oecused);
+	    }
+	}
+	noaliases = ona;
+	ecbuf[np] = n;
 	posix_in = isnewlin;
 	while (isnewlin)
-	  yylex();
-	if (tok == STRING && !strcmp(tokstr, "in")) {
-	    int np, n;
-
+	    yylex();
+        if (tok == STRING && !strcmp(tokstr, "in")) {
 	    incmdpos = 0;
 	    yylex();
 	    np = ecadd(0);
@@ -925,8 +938,6 @@
 	    ecbuf[np] = n;
 	    type = (sel ? WC_SELECT_LIST : WC_FOR_LIST);
 	} else if (!posix_in && tok == INPAR) {
-	    int np, n;
-
 	    incmdpos = 0;
 	    yylex();
 	    np = ecadd(0);
Index: Src/text.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/text.c,v
retrieving revision 1.5
diff -u -r1.5 text.c
--- Src/text.c	2000/12/05 10:34:23	1.5
+++ Src/text.c	2001/06/21 15:27:31
@@ -415,7 +415,7 @@
 		    taddstr(ecgetstr(state, EC_NODUP, NULL));
 		    taddstr(")) do");
 		} else {
-		    taddstr(ecgetstr(state, EC_NODUP, NULL));
+		    taddlist(state, *state->pc++);
 		    if (WC_FOR_TYPE(code) == WC_FOR_LIST) {
 			taddstr(" in ");
 			taddlist(state, *state->pc++);


-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR Ltd., Unit 300, Science Park, Milton Road,
Cambridge, CB4 0XL, UK                          Tel: +44 (0)1223 392070


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