DB
шо такое coverage condition?
Size: a a a
2020 November 12
YS
Так что - пустяки
AV
шо такое coverage condition?
Там написано!
DB
У меня некоторое время было в проде
IncoherentInstancesвырубай
YS
Вот с некогерентностью жить страшнее
YS
вырубай
выпилил уже
MK
шо такое coverage condition?
что-то из пейпера
DB
Там написано!
врёшь
AV
врёшь
слыш!
AV
The rules are these:
1 The Paterson Conditions: for each class constraint
1 No type variable has more occurrences in the constraint than in the head
2 The constraint has fewer constructors and variables (taken together and counting repetitions) than the head
3 The constraint mentions no type functions. A type function application can in principle expand to a type of arbitrary size, and so are rejected out of hand
2 The Coverage Condition. For each functional dependency, ⟨tvs⟩left
1 The Paterson Conditions: for each class constraint
(C t1 ... tn) in the context1 No type variable has more occurrences in the constraint than in the head
2 The constraint has fewer constructors and variables (taken together and counting repetitions) than the head
3 The constraint mentions no type functions. A type function application can in principle expand to a type of arbitrary size, and so are rejected out of hand
2 The Coverage Condition. For each functional dependency, ⟨tvs⟩left
-> ⟨tvs⟩right, of the class, every type variable in S(⟨tvs⟩right) must appear in S(⟨tvs⟩left), where S is the substitution mapping each type variable in the class declaration to the corresponding type in the instance head.DB
да блин!
DB
чо-то заумь какая-то
DB
сложна четать
AV
не спорю
MK
я же говорю
MK
тут вам не руби
AP
Опять академики намудрили!