gustav@tharr.UUCP (Paul Moore) (11/06/90)
I'm having a bit of trouble understanding how to use $* to handle multiline strings. I have a string, $article, which contains a large number of lines of text (OK, so it's a news article...) The article may end with any number of blank lines (ie, \n\n\n), which I want to remove. My first thought is $article =~ s/\n+$//, with $* = 0. But the manual says "Pattern matches on strings containing multiple newlines can produce confusing results when $* is 0". Um. However, if $* = 1, there seems to be no way of anchoring a pattern to the end (or the beginning) of a string. At this point, I started getting frustrated... Any clues, anybody? Thanks in advance, Gustav. -- /----------------------------------------------------------------\ | Paul Moore E-Mail: ...!ukc!tharr!gustav | | 10, Mulberry Rise or ...!ukc!cix!pmoore | | Northwich, Cheshire or (BEST) pmoore@cix.compulink.co.uk | <-- tharr *free* public access to Usenet in the UK 0234 261804 -->
piet@cs.ruu.nl (Piet van Oostrum) (11/06/90)
>>>>> In message <1391@tharr.UUCP>, gustav@tharr.UUCP (Paul Moore) (PM) writes:
PM> My first thought is $article =~ s/\n+$//, with $* = 0. But the manual says
PM> "Pattern matches on strings containing multiple newlines can produce
PM> confusing results when $* is 0". Um.
Larry will probably also comment on this, but in patch 19 it is stated that
from now on `$' will only match at string end (or at the newline just before
the end) when $*==0. So s/\n+$// works. Actually the only confusion that
remains is whether the LAST newline will be substituted. Maybe Larry can
give the rules.
Unfortunately, the manual ``page'' has not been updated with the patch.
--
Piet* van Oostrum, Dept of Computer Science, Utrecht University,
Padualaan 14, P.O. Box 80.089, 3508 TB Utrecht, The Netherlands.
Telephone: +31 30 531806 Uucp: uunet!mcsun!ruuinf!piet
Telefax: +31 30 513791 Internet: piet@cs.ruu.nl (*`Pete')lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall) (11/07/90)
In article <1391@tharr.UUCP> gustav@tharr.UUCP (Paul Moore) writes:
: I'm having a bit of trouble understanding how to use $* to handle
: multiline strings.
:
: I have a string, $article, which contains a large number of lines of
: text (OK, so it's a news article...) The article may end with any number
: of blank lines (ie, \n\n\n), which I want to remove.
:
: My first thought is $article =~ s/\n+$//, with $* = 0. But the manual says
: "Pattern matches on strings containing multiple newlines can produce
: confusing results when $* is 0". Um.
:
: However, if $* = 1, there seems to be no way of anchoring a pattern to
: the end (or the beginning) of a string.
:
: At this point, I started getting frustrated...
Actually, $* only applies to ^ and $, not \n. So just leave it 0, and
treat \n like a normal character, and it should work fine.
If it DOESN'T work fine, it's a bug.
The manual should definitely be clearer...
Larry