At 2001-08-18 06:15, Marcin 'Qrczak' Kowalczyk wrote:

Later additions to the function would have to be restricted to match at least one constructor defined in the current module, to make the combined definition independent of the order of additions - modules are by nature unordered.

Agreed.

And something more - this is not enough for unambiguous definition: -- Base definition foo :: SomeObject -> SomeObject -> Int foo _ _ = 0 -- Module 1 foo (SomeInt a) _ = 1 -- Module 2 foo _ (SomeString a) = 2 -- Which argument is evaluated as the first? -- What is called for foo (SomeInt 0) (SomeString "")?

The first argument would take priority. So Haskell would assemble these cases in this order: foo (SomeInt a) _ = 1 foo _ (SomeString a) = 2 foo _ _ = 0 If Module 2 included Module 1, it could do this: -- Module 2 foo _ (SomeString a) = 2 foo (SomeInt a) (SomeString a) = 2 In which case, the cases would be assembled in this order: foo (SomeInt a) (SomeString a) = 2 foo (SomeInt a) _ = 1 foo _ (SomeString a) = 2 foo _ _ = 0 -- Ashley Yakeley, Seattle WA