RE: [PHP] preg_match too greedy

2009-07-31 Thread Ford, Mike
 -Original Message-
 From: b [mailto:p...@logi.ca]
 Sent: 30 July 2009 03:17
 
 
 
  echo (preg_match($pattern, $test) != false)
 
  The  != false  here is redundant.
 
 Understood. But what you think is redundancy is, to me, clarity in
 programming. I happen to think that boolean tests shouldn't ride on
 whether or not an array returned from a function is empty or not (or
 a
 freaking boolean). If what I'm looking for is a false then that's
 what
 I'll test for.

Well, then, by that logic you should be testing separately for ===FALSE and 
===0, since the former means an error occurred, whilst the latter means the 
pattern was ok but didn't match.  If the pattern finds a match, the return 
value is 1 (not TRUE).


Cheers!

Mike
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Mike Ford,
Electronic Information Developer, Libraries and Learning Innovation,  
Leeds Metropolitan University, C507, Civic Quarter Campus, 
Woodhouse Lane, LEEDS,  LS1 3HE,  United Kingdom 
Email: m.f...@leedsmet.ac.uk 
Tel: +44 113 812 4730


  


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Re: [PHP] preg_match too greedy

2009-07-30 Thread Ben Dunlap
 echo (preg_match($pattern, $test) != false)

 The  != false  here is redundant.
 
 Understood. But what you think is redundancy is, to me, clarity in
 programming. I happen to think that boolean tests shouldn't ride on
 whether or not an array returned from a function is empty or not (or a
 freaking boolean). If what I'm looking for is a false then that's what
 I'll test for.

Fair enough, but in that case I think you want !== false. The expression you
have -- ($x != false) -- will be true whether $x is 0, NULL, an empty string,
an empty array, or actually FALSE.

But $x !== false will only be true in the last case.

Ben

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Re: [PHP] preg_match too greedy

2009-07-30 Thread Ben Dunlap
Ben Dunlap wrote:
 have -- ($x != false) -- will be true whether $x is 0, NULL, an empty 
 string,
[8]
 But $x !== false will only be true in the last case.

Sorry, replace be true with be false above.

-Ben

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[PHP] preg_match too greedy

2009-07-29 Thread b
I'm trying to figure out how to test if a string matches *exactly* 
another string, using a regexp pattern. The manual says that ereg() is 
deprecated (in favour of what?) and preg_match() is giving me trouble. 
The problem is that I'm passing the end-of-line delimiter ($) but it 
seems to be ignored. An example:


-- snip --
header('Content-type: text/plain');
$url = '/foo(/)?';
$test = 'foo/bar';
$pattern = '%^'.$url.'$%U';

echo ${url} :: ${test}\n;

echo (preg_match($pattern, $test) != false)
? 'match'
: 'no match';
-- snip --

I expected 'no match' but get 'match'.

The reason for the (/)? is to allow for a trailing slash. I've added a 
'$' to specify that I want to test for the exact string. However, 
preg_match() tests for the existence of a string and appears to ignore 
the '$'.


How do I do this?

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Re: [PHP] preg_match too greedy

2009-07-29 Thread Ben Dunlap
Jim Lucas wrote:
 I expected 'no match' but get 'match'.
[8]
 cut/paste your code and it works for me.

Works for me as well. I get 'no match' from PHP 5.1.2, 5.2.6, and 5.2.8. What
version do you have?

If I might suggest a couple of simplifications that would make it easier to
follow/troubleshoot:

 $url = '/foo(/)?';

I don't think you need parentheses around your second forward-slash. If you had
multiple characters that were optional you'd want to group them in parentheses,
but here I think it just makes the regex harder to read.

 echo (preg_match($pattern, $test) != false)

The  != false  here is redundant. Combined with the ternary operator, the
logical switchbacks make me a little dizzy (especially this close to lunchtime).

Ben

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Re: [PHP] preg_match too greedy

2009-07-29 Thread Jim Lucas
Ben Dunlap wrote:
 Jim Lucas wrote:
 I expected 'no match' but get 'match'.
 [8]
 cut/paste your code and it works for me.
 
 Works for me as well. I get 'no match' from PHP 5.1.2, 5.2.6, and 5.2.8. What
 version do you have?

PHP 5.2.5 with Suhosin-Patch 0.9.6.2 (cli) (built: Mar 11 2008 13:08:50)
Copyright (c) 1997-2007 The PHP Group
Zend Engine v2.2.0, Copyright (c) 1998-2007 Zend Technologies
  with Suhosin v0.9.20, Copyright (c) 2002-2006, by Hardened-PHP Project


 
 If I might suggest a couple of simplifications that would make it easier to
 follow/troubleshoot:
 
 $url = '/foo(/)?';
 
 I don't think you need parentheses around your second forward-slash. If you 
 had
 multiple characters that were optional you'd want to group them in 
 parentheses,
 but here I think it just makes the regex harder to read.
 
 echo (preg_match($pattern, $test) != false)
 
 The  != false  here is redundant. Combined with the ternary operator, the
 logical switchbacks make me a little dizzy (especially this close to 
 lunchtime).
 
 Ben
 



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Re: [PHP] preg_match too greedy

2009-07-29 Thread Daniel Kolbo
Jim Lucas wrote:
 Ben Dunlap wrote:
 Jim Lucas wrote:
 I expected 'no match' but get 'match'.
 [8]
 cut/paste your code and it works for me.
 Works for me as well. I get 'no match' from PHP 5.1.2, 5.2.6, and 5.2.8. What
 version do you have?
 
 PHP 5.2.5 with Suhosin-Patch 0.9.6.2 (cli) (built: Mar 11 2008 13:08:50)
 Copyright (c) 1997-2007 The PHP Group
 Zend Engine v2.2.0, Copyright (c) 1998-2007 Zend Technologies
   with Suhosin v0.9.20, Copyright (c) 2002-2006, by Hardened-PHP Project
 
 
 If I might suggest a couple of simplifications that would make it easier to
 follow/troubleshoot:

 $url = '/foo(/)?';
 I don't think you need parentheses around your second forward-slash. If you 
 had
 multiple characters that were optional you'd want to group them in 
 parentheses,
 but here I think it just makes the regex harder to read.

 echo (preg_match($pattern, $test) != false)
 The  != false  here is redundant. Combined with the ternary operator, the
 logical switchbacks make me a little dizzy (especially this close to 
 lunchtime).

 Ben

 
 
 
code works (no match) for me too on php 5.2.6 build date May 2 2008
18:01:20 with dumbdows NT.

preg_match fails but for a reason other than what I think you may be
expecting.  It fails b/c of the first forwards slash in $url.  The regex
engine doesn't even get past the second character let alone reaching the
end of line anchor.

Also, your code works (no match) with this first forward slash removed:
$url = 'foo(/)?'
This time preg_match fails due to the end of line anchor.
hth
dK
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Re: [PHP] preg_match too greedy

2009-07-29 Thread b

On 07/29/2009 02:07 PM, Jim Lucas wrote:

b wrote:

I'm trying to figure out how to test if a string matches *exactly*
another string, using a regexp pattern. The manual says that ereg() is
deprecated (in favour of what?) and preg_match() is giving me trouble.
The problem is that I'm passing the end-of-line delimiter ($) but it
seems to be ignored. An example:

-- snip --
header('Content-type: text/plain');
$url = '/foo(/)?';
$test = 'foo/bar';
$pattern = '%^'.$url.'$%U';

echo ${url} :: ${test}\n;

echo (preg_match($pattern, $test) != false)
 ? 'match'
 : 'no match';
-- snip --

I expected 'no match' but get 'match'.

The reason for the (/)? is to allow for a trailing slash. I've added a
'$' to specify that I want to test for the exact string. However,
preg_match() tests for the existence of a string and appears to ignore
the '$'.

How do I do this?



cut/paste your code and it works for me.

Jim Lucas



Works, meaning you get 'match', or 'no match'? It should be the latter, 
but I'm seeing the former.


I'm using 5.2.9, btw.

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Re: [PHP] preg_match too greedy

2009-07-29 Thread b

On 07/29/2009 03:03 PM, Ben Dunlap wrote:

Jim Lucas wrote:

I expected 'no match' but get 'match'.

[8]

cut/paste your code and it works for me.


Works for me as well. I get 'no match' from PHP 5.1.2, 5.2.6, and 5.2.8. What
version do you have?


5.2.9


If I might suggest a couple of simplifications that would make it easier to
follow/troubleshoot:


$url = '/foo(/)?';


I don't think you need parentheses around your second forward-slash. If you had
multiple characters that were optional you'd want to group them in parentheses,
but here I think it just makes the regex harder to read.


Really? I think it makes it crystal clear that it's the '/' that is 
optional. In any case, it makes no difference.





echo (preg_match($pattern, $test) != false)


The  != false  here is redundant.


Understood. But what you think is redundancy is, to me, clarity in 
programming. I happen to think that boolean tests shouldn't ride on 
whether or not an array returned from a function is empty or not (or a 
freaking boolean). If what I'm looking for is a false then that's what 
I'll test for.



Combined with the ternary operator, the logical switchbacks make me a

 little dizzy (especially this close to lunchtime).




Oh, you're one of those people who can't stand the sight of a ternary 
operator. Buck up, son, it's good for ya ;-)


(Seriously: I don't understand why ternaries freak some people out. It's 
plain as day!)



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Re: [PHP] preg_match too greedy

2009-07-29 Thread b

On 07/29/2009 07:48 PM, Daniel Kolbo wrote:


code works (no match) for me too on php 5.2.6 build date May 2 2008
18:01:20 with dumbdows NT.

preg_match fails but for a reason other than what I think you may be
expecting.  It fails b/c of the first forwards slash in $url.  The regex
engine doesn't even get past the second character let alone reaching the
end of line anchor.


The forward slash shouldn't be an issue as the delimiter is '%'. The 
full pattern is:


%^/foo/?$%U



Also, your code works (no match) with this first forward slash removed:
$url = 'foo(/)?'


But the string happens to start with a forward slash.


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Re: [PHP] preg_match too greedy

2009-07-29 Thread Daniel Kolbo
b wrote:
 On 07/29/2009 07:48 PM, Daniel Kolbo wrote:

 code works (no match) for me too on php 5.2.6 build date May 2 2008
 18:01:20 with dumbdows NT.

 preg_match fails but for a reason other than what I think you may be
 expecting.  It fails b/c of the first forwards slash in $url.  The regex
 engine doesn't even get past the second character let alone reaching the
 end of line anchor.
 
 The forward slash shouldn't be an issue as the delimiter is '%'. The
 full pattern is:
 
 %^/foo/?$%U
 
 
 Also, your code works (no match) with this first forward slash removed:
 $url = 'foo(/)?'
 
 But the string happens to start with a forward slash.
 
 
i am not talking about the delimiter
your pattern is:
%^/foo/?$%U
your test string is:
'foo/bar'

the first character of your pattern is a / and your first character of
your test string is an f.  They do not match.  The regex engine stops
after checking the first character.  This has nothing to do with
greediness or end of line anchors, but only with the first character
comparisons.

maybe what you wanted for your test string was
'/foo/bar'

This test string would then require your end of line anchor. Because the
end of line character does not match the b the engine stops.  No match.

This is consistent with the findings of others who replied to you.

Perhaps your regex engine has a different syntax for anchors.  For
example if your engine was seeing the carrot as a an exclusion operator
rather than being a beginning of line anchor and it was also, idk,
ignoring the dollar sign as your end of line anchor then you would get a
match.  But otherwise I would recommend you copy/paste the example you
provided and confirm that you still get a match.  Then i would confirm
your regex engine's anchor syntax.  Then, recompile your software
dK
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Re: [PHP] preg_match too greedy

2009-07-29 Thread b

On 07/29/2009 11:18 PM, Daniel Kolbo wrote:

b wrote:

On 07/29/2009 07:48 PM, Daniel Kolbo wrote:

code works (no match) for me too on php 5.2.6 build date May 2 2008
18:01:20 with dumbdows NT.

preg_match fails but for a reason other than what I think you may be
expecting.  It fails b/c of the first forwards slash in $url.  The regex
engine doesn't even get past the second character let alone reaching the
end of line anchor.

The forward slash shouldn't be an issue as the delimiter is '%'. The
full pattern is:

%^/foo/?$%U



Also, your code works (no match) with this first forward slash removed:
$url = 'foo(/)?'

But the string happens to start with a forward slash.



i am not talking about the delimiter
your pattern is:
%^/foo/?$%U
your test string is:
'foo/bar'


AAARRRGG! Sorry, that's a typo! It should be:

$test = '/foo/bar';

I guess that explains a lot. For the record, I had to type that in 
because this latest version of Thunderbird crashes whenever I paste into 
it. (note to self: downgrade that, stat!)






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