From: Peter Stephenson <pws@csr.com>
To: zsh-workers@sunsite.dk
Subject: Re: PATCH: CHR$(foo) => ${(#)foo}
Date: Tue, 1 Nov 2005 14:53:29 +0000 [thread overview]
Message-ID: <20051101145329.0a091880.pws@csr.com> (raw)
In-Reply-To: <200511011434.jA1EYf5B020570@news01.csr.com>
Peter Stephenson <pws@csr.com> wrote:
> There are lots of ways of turning a number into a character, but few the
> other way round, none that I'm aware of convenient for use in general
> substitutions. This adds the (#) expansion flag to do that. I couldn't
> think of a better syntax, certainly none I was likely to remember.
After posting this, I realised that handling arrays element by element was
much more natural (consistent enough with other forms of array processing
that it doesn't need specially documenting). You can do things like
% foo=(0x41 0x42 0x43)
% print ${(#j..)foo}
ABC
which was what I was trying to do in the first place.
Index: Doc/Zsh/expn.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/expn.yo,v
retrieving revision 1.56
diff -u -r1.56 expn.yo
--- Doc/Zsh/expn.yo 23 Sep 2005 17:03:17 -0000 1.56
+++ Doc/Zsh/expn.yo 1 Nov 2005 14:49:12 -0000
@@ -632,6 +632,11 @@
following flags are supported:
startitem()
+item(tt(#))(
+Evaluate the parameter as a numeric expression and output the character
+corresponding to the resulting integer. Note that this form is entirely
+distinct from use of the tt(#) without parentheses.
+)
item(tt(%))(
Expand all tt(%) escapes in the resulting words in the same way as in in
prompts (see noderef(Prompt Expansion)). If this flag is given twice,
Index: Src/subst.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/subst.c,v
retrieving revision 1.42
diff -u -r1.42 subst.c
--- Src/subst.c 13 Oct 2005 16:30:14 -0000 1.42
+++ Src/subst.c 1 Nov 2005 14:49:15 -0000
@@ -915,6 +915,10 @@
*/
int globsubst = isset(GLOBSUBST);
/*
+ * Indicates ${(#)...}.
+ */
+ int evalchar = 0;
+ /*
* Indicates ${#pm}, massaged by whichlen which is set by
* the (c), (w), and (W) flags to indicate how we take the length.
*/
@@ -1320,6 +1324,11 @@
unique = 1;
break;
+ case '#':
+ case Pound:
+ evalchar = 1;
+ break;
+
default:
flagerr:
zerr("error in flags", NULL, 0);
@@ -2233,6 +2242,40 @@
}
if (errflag)
return NULL;
+ if (evalchar) {
+ /*
+ * Evaluate the value numerically and output the result as
+ * a character.
+ *
+ * Note this doesn't yet handle Unicode or multibyte characters:
+ * that will need handling more generally probably by
+ * an additional flag of some sort.
+ */
+ zlong ires;
+
+ if (isarr) {
+ char **aval2, **avptr, **av2ptr;
+
+ aval2 = (char **)zhalloc((arrlen(aval)+1)*sizeof(char *));
+
+ for (avptr = aval, av2ptr = aval2; *avptr; avptr++, av2ptr++)
+ {
+ ires = mathevali(*avptr);
+ if (errflag)
+ return NULL;
+ *av2ptr = zhalloc(2);
+ sprintf(*av2ptr, "%c", (int)ires);
+ }
+ *av2ptr = NULL;
+ aval = aval2;
+ } else {
+ ires = mathevali(val);
+ if (errflag)
+ return NULL;
+ val = zhalloc(2);
+ sprintf(val, "%c", (int)ires);
+ }
+ }
/*
* This handles taking a length with ${#foo} and variations.
* TODO: again. one might naively have thought this had the
--
Peter Stephenson <pws@csr.com> Software Engineer
CSR PLC, Churchill House, Cambridge Business Park, Cowley Road
Cambridge, CB4 0WZ, UK Tel: +44 (0)1223 692070
This message has been scanned for viruses by BlackSpider MailControl - www.blackspider.com
next prev parent reply other threads:[~2005-11-01 14:53 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-11-01 14:34 Peter Stephenson
2005-11-01 14:53 ` Peter Stephenson [this message]
2005-11-01 17:20 ` Bart Schaefer
2005-11-01 17:46 ` Peter Stephenson
2005-11-01 18:17 ` Bart Schaefer
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