diff options
Diffstat (limited to 'ghc/compiler/utils/Maybes.lhs')
| -rw-r--r-- | ghc/compiler/utils/Maybes.lhs | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/ghc/compiler/utils/Maybes.lhs b/ghc/compiler/utils/Maybes.lhs index 2f6118fc91..6dd9251e66 100644 --- a/ghc/compiler/utils/Maybes.lhs +++ b/ghc/compiler/utils/Maybes.lhs @@ -5,7 +5,7 @@ \begin{code} module Maybes ( --- Maybe(..), -- no, it's in 1.3 + Maybe2(..), Maybe3(..), MaybeErr(..), orElse, @@ -38,6 +38,18 @@ infixr 4 `orElse` %************************************************************************ %* * +\subsection[Maybe2,3 types]{The @Maybe2@ and @Maybe3@ types} +%* * +%************************************************************************ + +\begin{code} +data Maybe2 a b = Just2 a b | Nothing2 deriving (Eq,Show) +data Maybe3 a b c = Just3 a b c | Nothing3 deriving (Eq,Show) +\end{code} + + +%************************************************************************ +%* * \subsection[Maybe type]{The @Maybe@ type} %* * %************************************************************************ @@ -173,3 +185,4 @@ returnMaB v = Succeeded v failMaB :: err -> MaybeErr val err failMaB e = Failed e \end{code} + |