use patterns for definitions instead of identifiers
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parent
19aa9410fb
commit
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3 changed files with 11 additions and 8 deletions
2
ast.hs
2
ast.hs
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@ -15,7 +15,7 @@ data AST = Add AST AST
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| Block [AST]
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| FunDef String (Pattern, AST)
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| Defun String AST
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| Def String AST
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| Def Pattern AST
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| Var String
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| Lambda [(Pattern, AST)]
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| Call String AST
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@ -219,10 +219,13 @@ eval (Defun name fn) = do
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newfn = FnV cls (oldpats ++ [(pat, body)]) in
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put (s, bind env name newfn) >> return newfn
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eval (Def name v') = do
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eval (Def pat v') = do
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v <- eval v'
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(s,env) <- get
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put (s, bind env name v)
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(s,locals:xs) <- get
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case patternBindings pat v of
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Nothing -> error $ "pattern binding doesn't satisfy: " ++ show v ++ " with " ++ show pat
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Just bindings ->
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put (s, (M.union bindings locals):xs) >> -- update our local bindings
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return v
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eval (Lambda pats) =
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@ -158,23 +158,23 @@ ifExpr = do
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bool = fmap BoolConst $ (symbol "true" >> return True) <|> (symbol "false" >> return False)
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def = do
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name <- identifier
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pat <- pattern
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whiteSpace
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symbol "="
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value <- exprparser
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return $ Def name value
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return $ Def pat value
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expr' = try block
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<|> try funDef
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<|> try call
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<|> try lambda
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<|> try def
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<|> try (emptyTuple TupleConst)
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<|> try (tupleSeq exprparser TupleConst)
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<|> parens exprparser
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<|> listSeq exprparser ListConst
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<|> try ifExpr
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<|> try bool
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<|> try def
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<|> fmap Var identifier
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<|> fmap StrConst stringLiteral
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<|> fmap IntConst integer
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