48 lines
No EOL
1.5 KiB
Haskell
48 lines
No EOL
1.5 KiB
Haskell
{-# LANGUAGE DeriveDataTypeable #-}
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module SourceSyntax.Declaration where
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import Data.Data
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import qualified SourceSyntax.Expression as Expr
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import SourceSyntax.Type
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import SourceSyntax.PrettyPrint
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import Text.PrettyPrint as P
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data Declaration tipe var
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= Definition (Expr.Def tipe var)
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| Datatype String [String] [(String,[Type])]
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| TypeAlias String [String] Type
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| ImportEvent String (Expr.LExpr tipe var) String Type
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| ExportEvent String String Type
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| Fixity Assoc Int String
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deriving (Eq, Show)
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data Assoc = L | N | R
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deriving (Eq)
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instance Show Assoc where
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show assoc =
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case assoc of
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L -> "left"
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N -> "non"
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R -> "right"
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instance Pretty (Declaration t v) where
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pretty decl =
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case decl of
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Definition def -> pretty def
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Datatype tipe tvars ctors ->
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P.hang (P.text "data" <+> P.text tipe <+> P.hsep (map P.text tvars)) 4
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(P.sep $ zipWith join ("=" : repeat "|") ctors)
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where
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join c ctor = P.text c <+> prettyCtor ctor
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prettyCtor (name, tipes) =
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P.hang (P.text name) 2 (P.sep (map prettyParens tipes))
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TypeAlias name tvars tipe ->
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let alias = P.text name <+> P.hsep (map P.text tvars) in
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P.hang (P.text "type" <+> alias <+> P.equals) 4 (pretty tipe)
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-- TODO: actually write out the other cases. They are currently unused, but
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-- this is probably going to be a bug someday.
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_ -> P.text (show decl) |