Zip with default value instead of dropping values?

Question

I\'m looking for a function in haskell to zip two lists that may vary in length.
All zip functions I could find just drop all values of a lists that is longer than the o

Answer 1

Here is another solution, that does work on infinite lists and is a straightforward upgrade of Prelude's zip functions:

zipDefault :: a ->  b -> [a] -> [b] -> [(a,b)]
zipDefault _da _db []     []     = []
zipDefault  da  db (a:as) []     = (a,db) : zipDefault da db as []
zipDefault  da  db []     (b:bs) = (da,b) : zipDefault da db [] bs
zipDefault  da  db (a:as) (b:bs) = (a,b)  : zipDefault da db as bs

and

zipDefaultWith :: a -> b -> (a->b->c) -> [a] -> [b] -> [c]
zipDefaultWith _da _db _f []     []     = []
zipDefaultWith  da  db  f (a:as) []     = f  a db : zipDefaultWith da db f as []
zipDefaultWith  da  db  f []     (b:bs) = f da  b : zipDefaultWith da db f [] bs
zipDefaultWith  da  db  f (a:as) (b:bs) = f  a  b : zipDefaultWith da db f as bs

@pigworker, thank you for your enlightening solution!