Re: (s) splitting – is there any way to provide «dynamic» separator

[Peter Stephenson <p.w.stephenson@ntlworld.com>]

On Thu, 09 Oct 2014 21:00:32 +0600
Vasiliy Ivanov <beelzebubbie.logs@gmail.com> wrote:
> Sorry if I (maybe) missed something obvious, but I failed to find a way to use separator from
> parameter (e.g. a='1:2:3'; sep=':'; print -l ${(s.$sep.)a}).
> I think this is because expansion/substitution are not available in
> flags? If so, is there any  another way for such a «dynamic» splitting?

I don't think you've missed anything obvious or elegant.

One way is

(){
  local IFS=$sep
  print -l ${=a}
}

Or if you can rely on not having whitespace

print -l ${=${a//:/ }}

Or, of course,

eval print -l '${(s.'$sep'.)a}'

as long as you can sanity check $sep.


Of course there's nothing to stop us adding a simple parameter
substitution as a special case at this point (or any similarly delimited
parameter argument) ...  Can't see how this can do much harm since it
sure as heck *looks* like a parameter expansion.

diff --git a/Src/subst.c b/Src/subst.c
index 1aa9b98..5727c12 100644
--- a/Src/subst.c
+++ b/Src/subst.c
@@ -1385,12 +1385,23 @@ static char *
 untok_and_escape(char *s, int escapes, int tok_arg)
 {
     int klen;
-    char *dst;
+    char *dst = NULL;
 
-    untokenize(dst = dupstring(s));
-    if (escapes) {
-	dst = getkeystring(dst, &klen, GETKEYS_SEP, NULL);
-	dst = metafy(dst, klen, META_HREALLOC);
+    if ((*s == String || *s == Qstring) && s[1]) {
+	char *pstart = s+1, *pend;
+	for (pend = pstart; *pend; pend++)
+	    if (!iident(*pend))
+		break;
+	if (!*pend) {
+	    dst = dupstring(getsparam(pstart));
+	}
+    }
+    if (dst == NULL) {
+	untokenize(dst = dupstring(s));
+	if (escapes) {
+	    dst = getkeystring(dst, &klen, GETKEYS_SEP, NULL);
+	    dst = metafy(dst, klen, META_HREALLOC);
+	}
     }
     if (tok_arg)
 	shtokenize(dst);

-- 
Peter Stephenson <p.w.stephenson@ntlworld.com>
Web page now at http://homepage.ntlworld.com/p.w.stephenson/