Prelude.Type.Match

Documentation

class Match a b p | a b -> p

Match

Used by Case to match patterns.

Match +a ?b -c Given a type a, match it with a pattern b, unifying the type variables. If it matches, c is True, otherwise c is False.

>>> value (T :: Match (Just True) (Just x) p => T '(x, p)) :: (Bool, Bool)
(True, True)

Match is in a seperate module because I use IncoherentInstances to match type variables.

Instances

Match Bool False True False

(~ Bool false False, ~ Bool match True) => Match Bool False false match

Match Bool True False False

(~ Bool true True, ~ Bool match True) => Match Bool True true match

Match Ordering LT EQ False

Match Ordering LT GT False

(~ Ordering lt LT, ~ Bool match True) => Match Ordering LT lt match

Match Ordering EQ LT False

Match Ordering EQ GT False

(~ Ordering eq EQ, ~ Bool match True) => Match Ordering EQ eq match

Match Ordering GT LT False

Match Ordering GT EQ False

(~ Ordering gt GT, ~ Bool match True) => Match Ordering GT gt match

~ () a b => Match () a b True

(~ k a b, ~ Bool p True) => Match k a b p

(~ Integer zeros Zeros, ~ Bool true True) => Match Integer Zeros zeros true

Match Integer Zeros Ones False

(~ Integer ones Ones, ~ Bool true True) => Match Integer Ones ones true

Match Integer Ones Zeros False

Match Integer Zeros (Zero j) False

Match Integer Zeros (One j) False

Match Integer Ones (Zero j) False

Match Integer Ones (One j) False

(~ Integer zero_j (Zero j), Match Integer i j p) => Match Integer (Zero i) zero_j p

Match Integer (Zero i) Zeros False

Match Integer (Zero i) Ones False

(~ Integer one_j (One j), Match Integer i j p) => Match Integer (One i) one_j p

Match Integer (One i) Zeros False

Match Integer (One i) Ones False

Match Integer (Zero i) (One i) False

Match Integer (One i) (Zero j) False

(~ [k] nil ([] k), ~ Bool true True) => Match [k] ([] k) nil true

(~ (Maybe k) nothing (Nothing k), ~ Bool true true) => Match (Maybe k) (Nothing k) nothing true

Match (Maybe k) (Nothing k) (Just k a) False

Match [k] ([] k) (: k x xs) False

(~ (Maybe k) just_b (Just k b), Match k a b p) => Match (Maybe k) (Just k a) just_b p

~ Bool false False => Match (Maybe k) (Just k a) (Nothing k) false

(~ [k] cons (: k y ys), Match k x y m, If Constraint m (Match [k] xs ys p) (~ Bool p False)) => Match [k] (: k x xs) cons p

Match [k] (: k x xs) ([] k) False

(~ (Either k k1) right_b (Right k k1 b), Match k1 a b p) => Match (Either k k1) (Right k k1 a) right_b p

(~ (Either k k1) left_b (Left k k1 b), Match k a b p) => Match (Either k k1) (Left k k1 a) left_b p

Match (Either k k1) (Right k k1 a) (Left k k1 b) False

Match (Either k k1) (Left k k1 a) (Right k k1 b) False

(~ ((,) k k1) e_f ((,) k k1 e f), Match k a e p, Match k1 b f q, ~ Bool r (&& p q)) => Match ((,) k k1) ((,) k k1 a b) e_f r

(~ ((,,) k k1 k2) e_f_g ((,,) k k1 k2 e f g), Match k a e p, Match k1 b f q, Match k2 c g r, ~ Bool (&& p q) s, ~ Bool (&& r s) t) => Match ((,,) k k1 k2) ((,,) k k1 k2 a b c) e_f_g t

(~ ((,,,) k k1 k2 k3) e_f_g_h ((,,,) k k1 k2 k3 e f g h), Match k a e p, Match k1 b f q, Match k2 c g r, Match k3 d h s, ~ Bool (&& p q) t, ~ Bool (&& r s) u, ~ Bool (&& t u) v) => Match ((,,,) k k1 k2 k3) ((,,,) k k1 k2 k3 a b c d) e_f_g_h v