[Haskell-cafe] how to get started: a text application

Max Ischenko max at ucmg.com.ua
Fri Jun 25 10:51:32 EDT 2004


Graham Klyne wrote:


> On reflection, I think there's a strong case for doing it this way (i.e. 
> with a separate tokenizer) in Haskell, even if the tokenization is very 
> simple, because it helps to separate some of the character-level issues 
> from the remaining program logic.  Any spurious detail that can be 
> separated from the core logic makes the core easier to understand.  

Yep.

> Divide and rule!  And, if I understand correctly, Haskell's lazy 
> evaluation should mean that there's little or no penalty for doing this, 
> even though it looks as if you're generating substantial intermediate data.

Fine. Though I'm not concerned with a perfomance, at least not until I 
get a first working version. ;)

> BTW, for a project like this, be very aware of the cost of using ++ to 
> append to a sequence.  Look at the ShowS type in the standard Prelude 
> (PreludeText).  I also made some notes about this [1].
> 
> [1] 
> http://www.ninebynine.org/Software/Learning-Haskell-Notes.html#UsingShowS

I skimmed through, and the whole page looks very instructive, thanks!



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