Difference between revisions of "Cookbook/Compilers and interpreters"
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(→GHCi) |
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| :i |
| :i |
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|<haskell> |
|<haskell> |
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| − | Prelude> :i |
+ | Prelude> :i Maybe |
| − | + | data Maybe a = Nothing | Just a -- Defined in Data.Maybe |
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| + | instance (Eq a) => Eq (Maybe a) -- Defined in Data.Maybe |
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| + | instance Monad Maybe -- Defined in Data.Maybe |
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| + | instance Functor Maybe -- Defined in Data.Maybe |
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| + | instance (Ord a) => Ord (Maybe a) -- Defined in Data.Maybe |
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| + | instance (Read a) => Read (Maybe a) -- Defined in GHC.Read |
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| + | instance (Show a) => Show (Maybe a) -- Defined in GHC.Show |
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</haskell> |
</haskell> |
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Revision as of 08:27, 31 August 2009
GHC
TODO
GHCi
| Problem | Solution | Examples |
|---|---|---|
| checking definitions | :i | Prelude> :i Maybe
data Maybe a = Nothing | Just a -- Defined in Data.Maybe
instance (Eq a) => Eq (Maybe a) -- Defined in Data.Maybe
instance Monad Maybe -- Defined in Data.Maybe
instance Functor Maybe -- Defined in Data.Maybe
instance (Ord a) => Ord (Maybe a) -- Defined in Data.Maybe
instance (Read a) => Read (Maybe a) -- Defined in GHC.Read
instance (Show a) => Show (Maybe a) -- Defined in GHC.Show
|
| checking types | :t | Prelude> :t "Hello"
"Hello" :: [Char]
|
Hugs
TODO