lawbreaker in HughesPJ
|Reported by:||maeder@…||Owned by:|
|Type of failure:||Difficulty:||Easy (less than 1 hour)|
|Test Case:||Blocked By:|
the law "empty is an identity for <> and $$" is currently broken by
ie. isEmpty (empty<>empty) as Conal Elliot noted.
Either the test isEmpty or the combinators <>, <+>, $$, $+$ need to be fixed. My suggested patch for the for 4 combinators caused an object code explosion (see ticket #490). I've also sent a simple patch for isEmpty that seems to be less optimal (as the reduction of a document may occur twice).
I could supply another patch of the 4 combinators where only the base cases are swapped.
This patch does not cause the explosion because the reordered base cases better fit to the left-associativity of the combinators. However, associativity does not help if one uses unfornate parentheses.
Anyway, HughesPJ should be fixed somehow