evaluated styles

[Sven Wischnowsky <wischnow@xxxxxxxxxxxxxxxxxxxxxxx>]

Just found an old patch I wanted to show you after 3.1.7...

We were discussing ways to make style-lookup evaluate some
user-defined code instead of just using the constant values. This
is as far as I got in terms of cleanness -- but, of course, no special 
syntax thing.

The patch adds the -e option to zstyle, to be used when defining
styles. The values of such styles will then be evaluated when looked
up and the value to return will be taken from $value (should that use
$reply instead?).

I don't plan to commit it (unless enough people get really excited
about it or we get suggestions for improvement).

Bye
 Sven

diff -u -r ../oz/Doc/Zsh/mod_zutil.yo ./Doc/Zsh/mod_zutil.yo
--- ../oz/Doc/Zsh/mod_zutil.yo	Mon May 29 19:04:34 2000
+++ ./Doc/Zsh/mod_zutil.yo	Tue May 30 19:49:33 2000
@@ -8,7 +8,7 @@
 startitem()
 findex(zstyle)
 xitem(tt(zstyle) [ tt(-L) ])
-xitem(tt(zstyle) [ tt(-) | tt(-)tt(-) ] var(pattern) var(style) var(strings) ...)
+xitem(tt(zstyle) [ tt(-e) | tt(-) | tt(-)tt(-) ] var(pattern) var(style) var(strings) ...)
 xitem(tt(zstyle -d) [ var(pattern) [ var(styles) ... ] ])
 xitem(tt(zstyle -g) var(name) [ var(pattern) [ var(style) ] ])
 xitem(tt(zstyle -abs) var(context) var(style) var(name) [ var(sep) ])
@@ -33,9 +33,14 @@
 done in the form of calls to tt(zstyle).  Forms with arguments:
 
 startitem()
-item(tt(zstyle) [ tt(-) | tt(-)tt(-) ] var(pattern) var(style) var(strings) ...)(
+item(tt(zstyle) [ tt(-e) | tt(-) | tt(-)tt(-) ] var(pattern) var(style) var(strings) ...)(
 Defines the given var(style) for the var(pattern) with the var(strings) as
-the value.
+the value.  If the tt(-e) option is given, the var(strings) will be
+concatenated (separated by spaces) and the resulting string will be
+evaluated when the style is looked up.  In this case the parameter
+tt(value) will be used to get the strings to return after the
+evaluation.  If tt(value) is not set, this will be treated as if the
+style were not set.
 )
 item(tt(zstyle -d) [ var(pattern) [ var(styles) ... ] ])(
 Delete style definitions. Without arguments all definitions are deleted,
diff -u -r ../oz/Src/Modules/zutil.c ./Src/Modules/zutil.c
--- ../oz/Src/Modules/zutil.c	Mon May 29 19:04:39 2000
+++ ./Src/Modules/zutil.c	Tue May 30 19:53:07 2000
@@ -48,6 +48,7 @@
     char *pat;			/* pattern string */
     Patprog prog;		/* compiled pattern */
     int weight;			/* how specific is the pattern? */
+    int eval;			/* eval-on-retrieve? */
     char **vals;
 };
     
@@ -102,7 +103,7 @@
 /* Store a value for a style. */
 
 static void
-setstypat(Style s, char *pat, Patprog prog, char **vals)
+setstypat(Style s, char *pat, Patprog prog, char **vals, int eval)
 {
     int weight, tmp, first;
     char *str;
@@ -116,6 +117,7 @@
 	    if (p->vals)
 		freearray(p->vals);
 	    p->vals = zarrdup(vals);
+	    p->eval = eval;
 
 	    return;
 	}
@@ -126,6 +128,7 @@
     p->pat = ztrdup(pat);
     p->prog = prog;
     p->vals = zarrdup(vals);
+    p->eval = eval;
     p->next = NULL;
 
     /* Calculate the weight. */
@@ -184,9 +187,36 @@
     return s;
 }
 
+static char **
+evalstyle(Stypat p)
+{
+    int ef = errflag;
+    Eprog prog = parse_string(sepjoin(p->vals, " ", 0), 0);
+    char **ret;
+
+    if (!prog) {
+	errflag = ef;
+	return NULL;
+    }
+    unsetparam("value");
+    execode(prog, 1, 0);
+    if (errflag) {
+	errflag = ef;
+	return NULL;
+    }
+    errflag = ef;
+
+    ret = getaparam("value");
+    if (ret)
+	ret = arrdup(ret);
+    unsetparam("value");
+
+    return ret;
+}
+
 /* Look up a style for a context pattern. This does the matching. */
 
-static Stypat
+static char **
 lookupstyle(char *ctxt, char *style)
 {
     Style s;
@@ -196,7 +226,7 @@
 	if (!strcmp(s->name, style))
 	    for (p = s->pats; p; p = p->next)
 		if (pattry(p->prog, ctxt))
-		    return p;
+		    return (p->eval ? evalstyle(p) : p->vals);
 
     return NULL;
 }
@@ -204,7 +234,7 @@
 static int
 bin_zstyle(char *nam, char **args, char *ops, int func)
 {
-    int min, max, n, add = 0, list = 0;
+    int min, max, n, add = 0, list = 0, eval = 0;
 
     if (!args[0])
 	list = 1;
@@ -218,6 +248,10 @@
 	    }
 	    if (oc == 'L')
 		list = 2;
+	    else if (oc == 'e') {
+		eval = add = 1;
+		args++;
+	    }
 	} else {
 	    add = 1;
 	    args++;
@@ -243,7 +277,7 @@
 	}
 	if (!(s = getstyle(args[1])))
 	    s = addstyle(args[1]);
-	setstypat(s, args[0], prog, args + 2);
+	setstypat(s, args[0], prog, args + 2, eval);
 
 	return 0;
     }
@@ -259,9 +293,9 @@
 	    }
 	    for (p = s->pats; p; p = p->next) {
 		if (list == 1)
-		    printf("    %s", p->pat);
+		    printf("%s  %s", (p->eval ? "(eval)" : "      "), p->pat);
 		else {
-		    printf("zstyle ");
+		    printf("zstyle %s", (p->eval ? "-e " : ""));
 		    quotedzputs(p->pat, stdout);
 		    printf(" %s", s->name);
 		}
@@ -343,12 +377,11 @@
 	break;
     case 's':
 	{
-	    Stypat s;
-	    char *ret;
+	    char **vals, *ret;
 	    int val;
 
-	    if ((s = lookupstyle(args[1], args[2])) && s->vals[0]) {
-		ret = sepjoin(s->vals, (args[4] ? args[4] : " "), 0);
+	    if ((vals = lookupstyle(args[1], args[2])) && vals[0]) {
+		ret = sepjoin(vals, (args[4] ? args[4] : " "), 0);
 		val = 0;
 	    } else {
 		ret = ztrdup("");
@@ -361,16 +394,15 @@
 	break;
     case 'b':
 	{
-	    Stypat s;
-	    char *ret;
+	    char **vals, *ret;
 	    int val;
 
-	    if ((s = lookupstyle(args[1], args[2])) &&
-		s->vals[0] && !s->vals[1] &&
-		(!strcmp(s->vals[0], "yes") ||
-		 !strcmp(s->vals[0], "true") ||
-		 !strcmp(s->vals[0], "on") ||
-		 !strcmp(s->vals[0], "1"))) {
+	    if ((vals = lookupstyle(args[1], args[2])) &&
+		vals[0] && !vals[1] &&
+		(!strcmp(vals[0], "yes") ||
+		 !strcmp(vals[0], "true") ||
+		 !strcmp(vals[0], "on") ||
+		 !strcmp(vals[0], "1"))) {
 		ret = "yes";
 		val = 0;
 	    } else {
@@ -384,12 +416,11 @@
 	break;
     case 'a':
 	{
-	    Stypat s;
-	    char **ret;
+	    char **vals, **ret;
 	    int val;
 
-	    if ((s = lookupstyle(args[1], args[2]))) {
-		ret = zarrdup(s->vals);
+	    if ((vals = lookupstyle(args[1], args[2]))) {
+		ret = zarrdup(vals);
 		val = 0;
 	    } else {
 		char *dummy = NULL;
@@ -405,14 +436,14 @@
     case 't':
     case 'T':
 	{
-	    Stypat s;
+	    char **vals;
 
-	    if ((s = lookupstyle(args[1], args[2])) && s->vals[0]) {
+	    if ((vals = lookupstyle(args[1], args[2])) && vals[0]) {
 		if (args[3]) {
 		    char **ap = args + 3, **p;
 
 		    while (*ap) {
-			p = s->vals;
+			p = vals;
 			while (*p)
 			    if (!strcmp(*ap, *p++))
 				return 0;
@@ -420,27 +451,25 @@
 		    }
 		    return 1;
 		} else
-		    return !(!strcmp(s->vals[0], "true") ||
-			     !strcmp(s->vals[0], "yes") ||
-			     !strcmp(s->vals[0], "on") ||
-			     !strcmp(s->vals[0], "1"));
+		    return !(!strcmp(vals[0], "true") ||
+			     !strcmp(vals[0], "yes") ||
+			     !strcmp(vals[0], "on") ||
+			     !strcmp(vals[0], "1"));
 	    }
-	    return (args[0][1] == 't' ? (s ? 1 : 2) : 0);
+	    return (args[0][1] == 't' ? (vals ? 1 : 2) : 0);
 	}
 	break;
     case 'm':
 	{
-	    Stypat s;
+	    char **vals;
 	    Patprog prog;
 
 	    tokenize(args[3]);
 
-	    if ((s = lookupstyle(args[1], args[2])) &&
+	    if ((vals = lookupstyle(args[1], args[2])) &&
 		(prog = patcompile(args[3], PAT_STATIC, NULL))) {
-		char **p = s->vals;
-
-		while (*p)
-		    if (pattry(prog, *p++))
+		while (*vals)
+		    if (pattry(prog, *vals++))
 			return 0;
 	    }
 	    return 1;

--
Sven Wischnowsky                         wischnow@xxxxxxxxxxxxxxxxxxxxxxx