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[Kon-Tiki]

Quick side-question... is it possible to make function in PHP of which an argument's not necessary? A function that'd be in the manual as function_name(int one, int two, [int three])

[Rogue]

What are you trying to do?

Replace [b] with <b>?

If that's the case, then use ereg(i)_replace.

[Kon-Tiki]

Or str_replace(), but it wouldn't make sure each [*b*]'d have a [/*b*], which's another thing that needs to be checked and fixed.

[Data]

uhm

function blah($arg1, $arg2=10) {

can be called like:
blah(10)
and blah(10,20)

[Rogue]

Then in reg. expression, you have to check for this:

'(\[b\])?(\[\/b\])'

or something like that.

So, you're looking for regular expression that in one line has both opening and closing tag, and use replace function to fix it.

I'm not sure if ? will work for all characters between, data might be able to tell you that. (or just check reference on the page you posted above)

When you are done, check for tags that have no matching opening/closing tag.

[plix]

Originally posted by Anubis@Jan 26 2006, 08:47 AM
Then in reg. expression, you have to check for this:
'(\[b\])?(\[\/b\])'

That wouldn't work as that statement doesn't require the opening bold tag to exist. A better (though not great) solution would be:

/\[b\](.*?)\[\/b\]/ig

which uses non-greedy matching (so you'd be best to use the perl regexp functions in PHP rather than the ereg functions).

If you're trying to write a forgiving BBCode parser and aren't just learning regexp then you're going about things all wrong. Regular expressions are for matching patterns, not for constructing push-down automata. Keep in mind that there's nesting and nesting requirements which regular expressions just can't handle well (it's possible with things like look-ahead and look-behind matching, but it's not pretty, it's not fast, and it's not reliable).

[Kon-Tiki]

How do you suggest I'd go 'bout it then?

[Reup]

Originally posted by plix@Jan 26 2006, 07:42 PM
it's possible with things like look-ahead and look-behind matching, but it's not pretty, it's not fast, and it's not reliable

Not to mention a b*tch to debug...

[plix]

Originally posted by Kon-Tiki+Jan 26 2006, 02:41 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Kon-Tiki @ Jan 26 2006, 02:41 PM)</td></tr><tr><td id='QUOTE'> How do you suggest I'd go 'bout it then? [/b]

<!--QuoteBegin-plix
Regular expressions are for matching patterns, not for constructing push-down automata.[/quote]
Use a push-down automaton (a finite state machine doesn't include a stack, which is necessary to do open- and close-tag matching. It's a bit harder to implement if you haven't written one before, but it's not only easier to maintain, it's much more flexible.

[Kon-Tiki]

Hmmm... I've never heard of a push-down automaton. I'll see if I can find a tutorial 'bout it k: