[clean-list] questions

[Jenda Krynicky]

From: fzuurbie@inter.nl.net
> > There's nothing better than regexps for string handling
> 
> Until you found out about combinator parsing (type this in in Google
> or CiteSeer). I have a library based on Koopman's and Rojemo's work
> (continuation passing style), extended with elaborated error messages.

If you need to PARSE a more complex expression than definitely the 
combinator parsing or some other kind of parser is in order. If you 
just want to extract something from a string or test whether it 
conforms to some not-too-complex format, then parsers (whether 
combinator based or any other) are overkill.

If e.g. I want to make sure that the stuff entered by the user is a 
date in YYYY-MM-DD format I definitely do not want to spend twenty 
cryptic lines writing a parser where
	/^(\d{4})-(\d{1,2})-(\d{1,2})$/
suffices. (I know you need to make sure the month is between 1 and 12 
and the day is reasonable, but you'd do that outside the parser as 
well.)

For certain type of tasks there is not anything better than regexs. 
For other tasks you need a parser. We should not ignore hacks just 
because by chainsaw you can cut down a tree quicker. Sometimes all 
you need is to chop a few logs.

Jenda
===== Jenda@Krynicky.cz === http://Jenda.Krynicky.cz =====
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