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Diffstat (limited to 'compiler/ilxGen/tests/test11.hs')
| -rw-r--r-- | compiler/ilxGen/tests/test11.hs | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/compiler/ilxGen/tests/test11.hs b/compiler/ilxGen/tests/test11.hs new file mode 100644 index 0000000000..ce53f71389 --- /dev/null +++ b/compiler/ilxGen/tests/test11.hs @@ -0,0 +1,61 @@ +{-# OPTIONS -fglasgow-exts #-} + +import PrelGHC + +class EEq a where + (===), (/==) :: a -> a -> Bool + +-- x /= y = not (x == y) +-- x == y = not (x /= y) +-- x /= y = True + (/==) x y = mynot ((===) x y) + x === y = True + +data EOrdering = ELT | EEQ | EGT + +mynot True = False +mynot False = True + +{- +class (EEq a) => EOrd a where + ecompare :: a -> a -> EOrdering + (<<), (<<=), (>>>=), (>>>):: a -> a -> Bool + emax, emin :: a -> a -> a + +-- An instance of Ord should define either compare or <= +-- Using compare can be more efficient for complex types. + ecompare x y + | x === y = EEQ + | x <<= y = ELT -- NB: must be '<=' not '<' to validate the + -- above claim about the minimal things that can + -- be defined for an instance of Ord + | otherwise = EGT + + x <<= y = case ecompare x y of { EGT -> False; _other -> True } + x << y = case ecompare x y of { ELT -> True; _other -> False } + x >>>= y = case ecompare x y of { ELT -> False; _other -> True } + x >>> y = case ecompare x y of { EGT -> True; _other -> False } + + -- These two default methods use '>' rather than compare + -- because the latter is often more expensive + emax x y = if x >>> y then x else y + emin x y = if x >>> y then y else x +-} + +data EInt = EI Int# + +ezeroInt, eoneInt, etwoInt, emaxInt, eminInt :: EInt +ezeroInt = EI 0# +eoneInt = EI 1# +etwoInt = EI 2# +eminInt = EI (-2147483648#) -- GHC <= 2.09 had this at -2147483647 +emaxInt = EI 2147483647# +eeqInt (EI x) (EI y) = x ==# y +eneInt (EI x) (EI y) = x /=# y + +instance EEq EInt where + (===) x y = x `eeqInt` y + (/==) x y = x `eneInt` y + +main = putStr (if (ezeroInt === eoneInt) then "no!\n" else "yes!\n") + |