Re: PATCH: 4.1: multi-parameter for loop

[Peter Stephenson <pws@xxxxxxx>]

Peter Stephenson wrote:
> This extends the for syntax to take multiple parameters after it; they take
> multiple words from the argument list.

Sorry, I didn't send the text.c chunk, without which this will crash
horribly.  Here's the complete thing.

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	2001/06/20 16:09:33
@@ -149,12 +149,20 @@
 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).
 )
 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
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	2001/06/20 16:09:33
@@ -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 1.23
diff -u -r1.23 parse.c
--- Src/parse.c	2001/06/18 07:34:34	1.23
+++ Src/parse.c	2001/06/20 16:09:34
@@ -903,15 +903,25 @@
 	yylex();
 	type = WC_FOR_COND;
     } else {
+	int np, n, isin = 0;
 	infor = 0;
 	if (tok != STRING || !isident(tokstr))
 	    YYERRORV(oecused);
-	ecstr(tokstr);
+	np = ecadd(0);
+	n = 0;
 	incmdpos = 1;
-	yylex();
-	if (tok == STRING && !strcmp(tokstr, "in")) {
-	    int np, n;
+	for (;;) {
+	    n++;
+	    ecstr(tokstr);
+	    yylex();	
+	    if (tok != STRING || (isin = !strcmp(tokstr, "in")) || sel)
+		break;
+	    if (!isident(tokstr))
+		YYERRORV(oecused);
+	}
+	ecbuf[np] = n;
 
+	if (isin) {
 	    incmdpos = 0;
 	    yylex();
 	    np = ecadd(0);
@@ -921,8 +931,6 @@
 	    ecbuf[np] = n;
 	    type = (sel ? WC_SELECT_LIST : WC_FOR_LIST);
 	} else if (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	2001/06/20 16:09:34
@@ -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@xxxxxxx>                  Software Engineer
CSR Ltd., Unit 300, Science Park, Milton Road,
Cambridge, CB4 0XL, UK                          Tel: +44 (0)1223 392070


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