12 Nov
2002
12 Nov
'02
2:06 p.m.
A simple, primitive question: has anybody here used in a non-trivial way the showsPrec anti-parser? My students asked me what is it for, it is never used in the Hugs Prelude, OK, once: possible parentheses around fractions n%d. I explained that it is a good contraption to make one own pretty- printers, like readsPrec can be useful for simple, precedence-based parsers. But I am still unhappy. The associativity is not taken into account, and for non-trivial purposes both ...Prec functions seem not as useful as I would like. Any comments? Thanks. Jerzy Karczmarczuk