In case that's not an adequate example, what I mean is, will this:
$ printf 'foo\nbar\n' | awk -v RS='()' -v ORS='X' '1' file
then produce the same output as this:
$ printf 'foo\nbar\n' | awk -v RS='^$' '{gsub(/()/,"X")}1'
XfXoXoX
XbXaXrX
X
or not and, if not, why is it different?
I just noticed that this seems to handle `/()/` differently from either
of the current cases again:
$ printf 'foo\nbar\n' | awk '{nf=split($0,flds,/()/,seps); print nf; for
(i=0; i<=nf; i++) printf "%s%s", flds[i], "<"seps[i]">" ; print ""}'
1
<>foo<>
1
<>bar<>
Regards,
Ed.
On 1/6/2021 2:54 PM, Ed Morton wrote:
Great! Will that treat `()` when used in an RS:
awk -v RS='()' -v ORS='x' '1'
the same as it's treated in a regexp in other contexts such as with
gsub():
awk -v ORS= '{gsub(/()/,"x")} 1'
or does it mean something different when used in an RS?
Ed.
On 1/6/2021 1:33 PM, arnold@skeeve.com wrote:
Hi. Re this:
Ed Morton<mortoneccc@comcast.net> wrote:
Someone just pointed this out to me (gawk 5.1.0):
$ printf 'foo\n' | awk '{gsub(/()/,"x")} 1'
xfxoxox
$ printf 'foo\n' | awk -v RS='()' -v ORS='x\n' '1'
foox
Obviously that's a pretty ridiculous regexp but it still has me
wondering - why does `gsub()` treat the regexp `()` as matching a null
string around every character while `RS` treats it as if I'd asked it to
match the `\n` at the end of the input:
$ printf 'foo\n' | awk -v RS='\n$' -v ORS='x\n' '1'
foox
I could just file this under "don't write stupid regexps" but I was
wondering if there's a more concrete, satisfying explanation of the
behavior.
Ed.
It's a bug. This appears to be the fix. It doesn't break the
test suite, either.
Thanks for the report!
Arnold
-----------------------------------------
diff --git a/io.c b/io.c
index 2714398e..0af8ab1e 100644
--- a/io.c
+++ b/io.c
@@ -3702,7 +3702,7 @@ again:
* If still room in buffer, skip over null match
* and restart search. Otherwise, return.
*/
- if (bp + iop->scanoff < iop->dataend) {
+ if (bp + iop->scanoff <= iop->dataend) {
bp += iop->scanoff;
goto again;
}