31 lines
1 KiB
Haskell
31 lines
1 KiB
Haskell
{-# OPTIONS_GHC -Wall #-}
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module Transform.Definition where
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import Control.Applicative ((<$>))
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import qualified SourceSyntax.Pattern as P
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import SourceSyntax.Expression
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import qualified Transform.Expression as Expr
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combineAnnotations :: [ParseDef] -> Either String [Def]
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combineAnnotations = go
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where
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msg x = "Syntax Error: The type annotation for '" ++ x ++
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"' must be directly above its definition."
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exprCombineAnnotations = Expr.crawlLet combineAnnotations
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go defs =
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case defs of
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TypeAnnotation name tipe : Def pat@(P.Var name') expr : rest | name == name' ->
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do expr' <- exprCombineAnnotations expr
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let def = Definition pat expr' (Just tipe)
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(:) def <$> go rest
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TypeAnnotation name _ : _ -> Left (msg name)
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Def pat expr : rest ->
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do expr' <- exprCombineAnnotations expr
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let def = Definition pat expr' Nothing
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(:) def <$> go rest
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[] -> return []
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