Re: split on empty string

2006-01-18 Thread David K Storrs 


On Jan 18, 2006, at 1:18 AM, Jonathan Scott Duff wrote:


On Tue, Jan 17, 2006 at 12:35:57PM -0500, Mark Reed wrote:

On 2006-01-17 12:24 PM, Gaal Yahas [EMAIL PROTECTED] wrote:

[split on empty string] doesn's seem to be specced yet.


I would prefer the current pugs behavior; it's consistent with the  
general
case, in which a string which does not match the splitting regex  
results in
a single-item list containing the original string.  This is the  
Python

behavior.

I find the Perl5 (and, surprisingly, Ruby) behavior rather  
counterintuitive.


FWIW, I agree with Mark.

-Scott


Just to show opposite, I've always found that behavior (i.e.  
returning the original string unchanged) confusing.  Csplit works  
based on sequential examination of the target string to locate  
matching substrings on which to split.  There is a matching empty  
string substring between every character.  Naturally, what you get  
back is an array of characters.


Plus, it's a useful idiom.

--Dks

Re: split on empty string

2006-01-18 Thread Mark Reed 
On 2006-01-18 10:04 AM, David K Storrs [EMAIL PROTECTED] wrote:
 Just to show opposite, I've always found that behavior (i.e.
 returning the original string unchanged) confusing.  Csplit works
 based on sequential examination of the target string to locate
 matching substrings on which to split.  There is a matching empty
 string substring between every character.  Naturally, what you get
 back is an array of characters.
 
 Plus, it's a useful idiom.

You misunderstand.  We're not talking about splitting a string with the
empty string as the delimiter.  We're talking about splitting the empty
string (as the target), with any delimiter whatsoever.  If you do that, what
you get back is an empty array.

Perl6 .split(/whatever/) is equivalent to split(/whatever/,) in Perl5.
It's not like the silly Python idiom where the invocant is the delimiter
string. :)

So this is the Perl5 to which I was referring:

   my @result = split(/whatever/, );
   print [EMAIL PROTECTED],\n;# -- 0

The general case I was comparing it to is when the target string is *not*
empty but doesn't match, in which case you get the original string back:

my @result = split(/foo/, bar);
print [EMAIL PROTECTED],\n;# -- 1
print $result[0],\n;   # -- bar

Re: split on empty string

2006-01-18 Thread Jonathan Lang 
Mark Reed wrote:
 Perl6 .split(/whatever/) is equivalent to split(/whatever/,) in Perl5.

I'm hoping that the perl 5 syntax will still be valid in perl 6.

--
Jonathan Dataweaver Lang

Re: split on empty string

2006-01-18 Thread Larry Wall 
On Tue, Jan 17, 2006 at 07:24:14PM +0200, Gaal Yahas wrote:
: While cleaning up tests for release:
: 
: .split(':')=
: 
:()# Perl 5
:(,) # pugs
: 
: Which is correct? It doesn's seem to be specced yet.

This has nothing to do with splitting on the empty string, per se, but
with Perl 5 stripping trailing null fields by default:

@results = split(/:/,'');
print @results + 0; # prints '0'

I think we could make that behavior optional now with :trim or some
such.  The original motivation has largely gone away with the advent
of autochomping filehandles, so split /\s+/ won't produce a spurious
null field after the \n.

Larry

Re: split on empty string

2006-01-18 Thread Juerd 
Jonathan Lang skribis 2006-01-18  7:26 (-0800):
 Mark Reed wrote:
  Perl6 .split(/whatever/) is equivalent to split(/whatever/,) in Perl5.
 I'm hoping that the perl 5 syntax will still be valid in perl 6.

Don't worry, it is.


Juerd
-- 
http://convolution.nl/maak_juerd_blij.html
http://convolution.nl/make_juerd_happy.html 
http://convolution.nl/gajigu_juerd_n.html

Re: split on empty string

2006-01-18 Thread Larry Wall 
On Wed, Jan 18, 2006 at 09:08:07PM +0100, Juerd wrote:
: Jonathan Lang skribis 2006-01-18  7:26 (-0800):
:  Mark Reed wrote:
:   Perl6 .split(/whatever/) is equivalent to split(/whatever/,) in Perl5.
:  I'm hoping that the perl 5 syntax will still be valid in perl 6.
: 
: Don't worry, it is.

Yep, it's mostly just the semantics we're screwing around with.  :-)

Larry

Re: split on empty string

2006-01-17 Thread Mark Reed 
On 2006-01-17 12:24 PM, Gaal Yahas [EMAIL PROTECTED] wrote:

 While cleaning up tests for release:
 
 .split(':')=
 
()# Perl 5
(,) # pugs
 
 Which is correct? It doesn's seem to be specced yet.

I would prefer the current pugs behavior; it's consistent with the general
case, in which a string which does not match the splitting regex results in
a single-item list containing the original string.  This is the Python
behavior.

I find the Perl5 (and, surprisingly, Ruby) behavior rather counterintuitive.

split on empty string

2006-01-17 Thread Gaal Yahas 
While cleaning up tests for release:

.split(':')=

   ()# Perl 5
   (,) # pugs

Which is correct? It doesn's seem to be specced yet.

-- 
Gaal Yahas [EMAIL PROTECTED]
http://gaal.livejournal.com/

Re: split on empty string

2006-01-17 Thread Jonathan Scott Duff 
On Tue, Jan 17, 2006 at 12:35:57PM -0500, Mark Reed wrote:
 On 2006-01-17 12:24 PM, Gaal Yahas [EMAIL PROTECTED] wrote:
 
  While cleaning up tests for release:
  
  .split(':')=
  
 ()# Perl 5
 (,) # pugs
  
  Which is correct? It doesn's seem to be specced yet.
 
 I would prefer the current pugs behavior; it's consistent with the general
 case, in which a string which does not match the splitting regex results in
 a single-item list containing the original string.  This is the Python
 behavior.
 
 I find the Perl5 (and, surprisingly, Ruby) behavior rather counterintuitive.

FWIW, I agree with Mark.

-Scott
-- 
Jonathan Scott Duff
[EMAIL PROTECTED]