lawbreaker in HughesPJ
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 (closed)). 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 Cheers Christian
Trac metadata
Trac field | Value |
---|---|
Version | 6.4.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | libraries/base |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | Unknown |
Architecture | Unknown |