28 lines
1.1 KiB
Haskell
28 lines
1.1 KiB
Haskell
module Substitute (subst) where
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import Ast
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import Context
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import Control.Arrow (second, (***))
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subst :: String -> Expr -> Expr -> Expr
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subst old new expr =
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let f (C t s e) = C t s (subst old new e) in
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case expr of
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Range e1 e2 -> Range (f e1) (f e2)
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Access e x -> Access (f e) x
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Remove e x -> Remove (f e) x
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Insert e x v -> Insert (f e) x (f v)
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Modify r fs -> Modify (f r) (map (second f) fs)
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Record fs -> Record (map (\(lbl,as,e) -> (lbl,as,f e)) fs)
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Binop op e1 e2 -> Binop op (f e1) (f e2)
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Lambda x e -> if x == old then expr else Lambda x (f e)
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App e1 e2 -> App (f e1) (f e2)
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If e1 e2 e3 -> If (f e1) (f e2) (f e3)
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MultiIf ps -> MultiIf (map (f *** f) ps)
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Let defs e -> Let (map substDef defs) (f e)
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where substDef (FnDef name vs e) = FnDef name vs (f e)
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substDef (OpDef op a1 a2 e) = OpDef op a1 a2 (f e)
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Var x -> if x == old then new else expr
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Case e cases -> Case (f e) $ map (second f) cases
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Data name es -> Data name (map f es)
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_ -> expr
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