[Haskell-cafe] Another Question

[Navin Rustagi]

hi , 

I am stuck in the following problem. 

I am maintaining  a list of  tuples of the form 
([Char],Int,Int, Int,Int) . The purpose of maintaining the tuples is that the 
program reads from a file line by line , Matches the contents with the first 
element of the tuple and updates the tuple respectively.

The precise function I am using is as follows 


tupup::Bool->[Char]->Int->Int->Int->Int->Char->([Char],Int,Int,Int,Int) 
tupup val elf els elr ell elx ys= if val then 
                                          case ys of  'A'  -> (elf, 
els+1,elr,ell,elx) 
                                                      'G'  -> (elf,els, elr 
+1,ell,elx)
                                                      'C'  -> (elf,els,elr,  ell 
+1,elx) 
                                                      'T'  -> (elf,els,elr,ell, 
 elx +1)
                                           else (elf,els,elr,ell,elx)


uptable::[[Char]]->[([Char],Int,Int,Int,Int)]->[([Char],Int,Int,Int,Int)]
uptable (xf:xs) main_array = map (\(x,y,z,r,t)-> tupup (x==xf) x y z r t 
(secvalue xs) ) main_array
   
 
It gives the error ERROR - Control stack overflow. I assume it is because of the 
lazy evaluation . 
Is there a way to enforce strict evaluation only for the function tupup. 



Thanks, 

Navin 


      
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