Veli-Pekka
You're implying that the music macro language is pos() sensitive.
That is a pretty severe problem in itself.
Can you output the macro language in a format that is not position
sensitive - do a global change - then process the macro language back
into original format?
I think I'd be more inclined to use a "$noteindex{$note} = $pitch"
hash table than a regex - then process the input one note at a time.
KenMc
On Oct 9, 2005, at 2:58 PM, Veli-Pekka Tätilä wrote:
Hi,
Yet another newbie question about regular expressions:
I'd like to find and replace bits of text as usual. However, rather
than replace all occurrences in one quick swoop using the s-
operator and the g-flag, the replacement is so complex that it
cannot be expressed as a straight substitution. So I would have to
find a piece of text, process it in a separate function, and
replace the matched text with the newly computed text. This goes on
for n interesting matches in the input.
Can I do this kind of thing in a simple loop, processing all
matches one by one? My understanding is that pos and some special
variables will tel me the character index of the mach in a string.
But if I then go and modify the string using substr to do the
substitution, wil it reset the search position to the beginning
when trying to match the next interesting bit? The replacement text
is by nature longer than the original so the input string needs to
grow on each substitution which might present a problem to the
matching operator. I took a look at perlop and some books I have on
Perl but didn't end up with a definitive answer of how I should
solve this problem.
That was the problem abstractly put, here's the specific instance:
I'm writing a program to convert notes given in the music macro
language to their equivalent pitches that are applied using markup
tags for speech synthesizers. I can match a note easily, and have
functions for computing the pitch and the tag in question. As the
note values don't depend on each other in any way, I'd like to
completely process one note at a time, doing the replacement, and
then continue matching the next note where it previously left off.
Naturally there are other tokens than just notes in the input so I
need to maintain the position of the note data in the input string.
If I modify a separate copy of the string, it will throw off the pos
() indeces because the substitutions will change the length of the
copy.
Any help appreciated as usual.
PS: If the problem statement is still a bit fuzzy or incomplete,
just ask and I'll try to provide more info.
--
With kind regards Veli-Pekka Tätilä ([EMAIL PROTECTED])
Accessibility, game music, synthesizers and programming:
http://www.student.oulu.fi/~vtatila/
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