From: Mikael Magnusson <mikachu@gmail.com>
To: zsh-workers@zsh.org
Subject: PATCH: Add :^ syntax for zipping two arrays (v2)
Date: Fri, 1 Aug 2014 17:47:38 +0200 [thread overview]
Message-ID: <1406908058-7730-1-git-send-email-mikachu@gmail.com> (raw)
Here's my current version with :^ and :^^ and using heap alloc including hmkarray.
---
Doc/Zsh/expn.yo | 17 +++++++++++++++++
Src/subst.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 73 insertions(+)
diff --git a/Doc/Zsh/expn.yo b/Doc/Zsh/expn.yo
index ff9f2b1..4d28d86 100644
--- a/Doc/Zsh/expn.yo
+++ b/Doc/Zsh/expn.yo
@@ -636,6 +636,23 @@ Similar to the preceding subsitution, but in the opposite sense,
so that entries present in both the original substitution and as
elements of var(arrayname) are retained and others removed.
)
+xitem(tt(${)var(name)tt(:^)var(arrayname)tt(}))
+item(tt(${)var(name)tt(:^^)var(arrayname)tt(}))(
+Zips two arrays, such that the output array is twice as long as the
+shortest (longest for `tt(:^^)') of tt(name) and tt(arrayname), with
+the elements alternatingly being picked from them. For `tt(:^)', if one
+of the input arrays is longer, the output will stop when the end of the
+shorter array is reached. Thus,
+
+example(a=(1 2 3 4); b=(a b); print ${a:^b})
+
+will output `tt(1 a 2 b)'. For `tt(:^^)', then the input is repeated
+until all of the longer array has been used up and the above will output
+`tt(1 a 2 b 3 a 4 b)'.
+
+Either or both inputs may be a scalar, they will be treated as an array
+of length 1 with the scalar as the only element.
+)
xitem(tt(${)var(name)tt(:)var(offset)tt(}))
item(tt(${)var(name)tt(:)var(offset)tt(:)var(length)tt(}))(
This syntax gives effects similar to parameter subscripting
diff --git a/Src/subst.c b/Src/subst.c
index 944492f..21e1a1a 100644
--- a/Src/subst.c
+++ b/Src/subst.c
@@ -2878,6 +2878,62 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags)
}
break;
}
+ } else if (inbrace && (*s == '^' || *s == Hat)) {
+ char **zip, **ap, **apsrc;
+ int shortest = 1;
+ ++s;
+ if (*s == '^' || *s == Hat) {
+ shortest = 0;
+ ++s;
+ }
+ if (*itype_end(s, IIDENT, 0)) {
+ untokenize(s);
+ zerr("not an identifier: %s", s);
+ return NULL;
+ }
+ if (vunset) {
+ if (unset(UNSET)) {
+ *idend = '\0';
+ zerr("%s: parameter not set", idbeg);
+ return NULL;
+ }
+ val = dupstring("");
+ } else {
+ char *sval;
+ zip = getaparam(s);
+ if (!zip) {
+ sval = getsparam(s);
+ if (sval)
+ zip = hmkarray(sval);
+ }
+ if (!isarr) aval = mkarray(val);
+ if (zip) {
+ char **out;
+ int alen, ziplen, outlen, i = 0;
+ alen = arrlen(aval);
+ ziplen = arrlen(zip);
+ outlen = shortest ^ (alen > ziplen) ? alen : ziplen;
+ out = zhalloc(sizeof(char *) * (2 * outlen + 1));
+ while (i < outlen) {
+ if (copied)
+ out[i*2] = aval[i % alen];
+ else
+ out[i*2] = dupstring(aval[i % alen]);
+ out[i*2+1] = dupstring(zip[i % ziplen]);
+ i++;
+ }
+ out[i*2] = NULL;
+ aval = out;
+ copied = 1;
+ isarr = 1;
+ } else {
+ if (unset(UNSET)) {
+ zerr("%s: parameter not set", s);
+ return NULL;
+ }
+ val = dupstring("");
+ }
+ }
} else if (inbrace && (*s == '|' || *s == Bar ||
*s == '*' || *s == Star)) {
int intersect = (*s == '*' || *s == Star);
--
1.9.0
next reply other threads:[~2014-08-01 17:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-01 15:47 Mikael Magnusson [this message]
2014-08-04 8:29 ` Peter Stephenson
2014-08-04 16:01 ` Mikael Magnusson
2014-08-04 16:07 ` Peter Stephenson
2014-08-04 16:51 ` PATCH: Add :^ syntax for zipping two arrays (v3) Mikael Magnusson
2014-08-04 18:36 ` Bart Schaefer
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