Hi,
I'd like to create a new list based on an original list, using information from
a second (symbol) list. That second list should be updated as each element in
the new list is added. I've been using map a lot, but that's not an option
here, and I'm having trouble obtaining a good recursive structure for my
function.
The minimal "fixpus" function below shows the problem. I have "sts" on both
sides of the ":" list construct, but I'd like the second "sts" to be a version
modified by the where (singular) function, "fixpu".
fixpus :: [ProgUnit] -> [ProgUnitSymbolTable] -> [ProgUnit]
fixpus [] _ = []
fixpus (pu:pus) sts = fixpu pu sts : fixpus pus sts
where fixpu pu sts = pu
(Below) I tried making "fixpu" return a tuple, and then use "fst", "snd" and
"let", but I think it looks strange. I know it's quite basic, but I'd like a
strong foundation for what's likely to become a medium-scale project. Can
anyone offer advice?
fixpus :: [ProgUnit] -> [ProgUnitSymbolTable] -> [ProgUnit]
fixpus [] _ = []
fixpus (pu:pus) sts = let a = (fixpu pu sts) in fst a : fixpus pus (snd a)
where fixpu pu sts = (pu,sts ++ [("",[])])
Regards,
Paul
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