1 implementation module parse
6 from StdFunc import const
11 import Control.Applicative
13 from Text import class Text(concat), instance Text String
18 parser :: LexerOutput -> ParserOutput
19 parser (Left e) = Left $ toString $ LexError e
20 parser (Right r) = case runParser parseProgram r of
21 (Right p, _) = Right p
22 (Left e, _) = Left $ toString e
24 parseProgram :: Parser Token AST
25 parseProgram = some parseVarDecl
26 >>= \vd->pure $ AST vd []
28 parseFunDecl :: Parser Token FunDecl
31 parseVarDecl :: Parser Token VarDecl
33 (parseType <|> trans1 VarToken VarType )
34 >>= \t->parseIdent <* satTok AssignmentToken
35 >>= \i->parseExpr <* satTok SColonToken
36 >>= \e->pure $ VarDecl i t e
38 parseType :: Parser Token Type
40 trans1 IntTypeToken IntType <|>
41 trans1 CharTypeToken CharType <|>
42 trans1 BoolTypeToken BoolType <|>
43 (satTok SquareOpenToken *> parseType <* satTok SquareCloseToken
44 >>= \t.pure $ ListType t) <|>
45 (satTok BraceOpenToken *> parseType <* satTok CommaToken
46 >>= \t1->parseType <* satTok BraceCloseToken
47 >>= \t2->pure $ TupleType t1 t2) <|>
48 (parseIdent >>= \e.pure $ IdType e) <|>
51 parseExpr :: Parser Token Expr
53 parseOpRight (trans1 ColonToken BiCons) $
54 parseOpRight (trans1 PipesToken BiOr) $
55 parseOpRight (trans1 AmpersandsToken BiAnd) $
56 parseOpRight (trans1 EqualsToken BiEquals <|>
57 trans1 LesserToken BiLesser <|>
58 trans1 BiggerToken BiGreater <|>
59 trans1 LesserEqToken BiLesserEq <|>
60 trans1 GreaterEqToken BiGreaterEq <|>
61 trans1 NotEqualToken BiUnEqual) $
62 parseOpLeft (trans1 PlusToken BiPlus <|>
63 trans1 DashToken BiMinus) $
64 parseOpLeft (trans1 StarToken BiTimes <|>
65 trans1 SlashToken BiDivide <|>
66 trans1 PercentToken BiMod) $
69 parseOpRight :: (Parser Token Op2) (Parser Token Expr) -> Parser Token Expr
70 parseOpRight ops prev = prev >>= \e1->optional (
71 ops >>= \op->parseOpRight ops prev >>= \e->pure (op, e)
72 ) >>= \moe->pure $ maybe e1 (\(op,e2)->Op2Expr e1 op e2) moe
74 parseOpLeft :: (Parser Token Op2) (Parser Token Expr) -> Parser Token Expr
75 parseOpLeft ops prev = prev >>= \e1->many (
76 ops >>= \op->prev >>= \e->pure (op, e)
77 ) >>= \moe->foldM (\e->(\(op,e2)->pure $ Op2Expr e op e2)) e1 moe
79 parseBasicExpr :: Parser Token Expr
81 (satTok BraceOpenToken *> parseExpr <* satTok BraceCloseToken) <|>
82 (satTok BraceOpenToken *> parseExpr <* satTok CommaToken
83 >>= \e1->parseExpr <* satTok BraceCloseToken
84 >>= \e2->pure $ TupleExpr e1 e2) <|>
85 trans1 EmptyListToken EmptyListExpr <|>
86 trans2 TrueToken (const $ BoolExpr True) <|>
87 trans2 FalseToken (const $ BoolExpr False) <|>
88 trans2 (NumberToken zero) (\(NumberToken i)->IntExpr i) <|>
89 trans2 (CharToken zero) (\(CharToken c)->CharExpr c) <|>
90 (parseOp1 >>= \o->parseExpr >>= \e.pure $ Op1Expr o e) <|>
91 (parseIdent <* satTok BraceOpenToken
92 >>= \i->parseActArgs <* satTok BraceCloseToken
93 >>= \es->pure $ FunExpr i es) <|>
94 (parseIdent >>= \i. parseFieldSelector >>= \f.pure $ VarExpr i f)
96 parseActArgs :: Parser Token [Expr]
98 (some (parseExpr <* satTok CommaToken) >>= \es->parseExpr
99 >>= \e.pure [e:es]) <|>
100 (parseExpr >>= \e->pure [e]) <|>
103 parseOp1 :: Parser Token Op1
104 parseOp1 = trans1 DashToken UnMinus <|>
105 trans1 ExclamationToken UnNegation
107 parseFieldSelector :: Parser Token (Maybe FieldSelector)
108 parseFieldSelector = optional (satTok DotToken *> (
109 (parseIdent >>= (\i.if (i == "hd") (pure FieldHd) empty)) <|>
110 (parseIdent >>= \i.if (i == "tl") (pure FieldTl) empty) <|>
111 (parseIdent >>= \i.if (i == "fst") (pure FieldFst) empty) <|>
112 (parseIdent >>= \i.if (i == "snd") (pure FieldSnd) empty)))
114 trans2 :: TokenValue (TokenValue -> a) -> Parser Token a
115 trans2 t f = satTok t >>= \(_, r).pure (f r)
117 trans1 :: TokenValue a -> Parser Token a
118 trans1 t r = trans2 t $ const r
120 satTok :: TokenValue -> Parser Token Token
121 satTok t = satisfy ((===) t)
123 parseIdent :: Parser Token String
124 parseIdent = trans2 (IdentToken []) (\(IdentToken e).toString e)
126 instance toString AST where
127 toString (AST v f) = concat (print v ++ ["\n":print f])
129 class print a :: a -> [String]
131 instance print [a] | print a where
133 print [v:vs] = print v ++ ["\n":print vs]
135 instance print VarDecl where
136 print (VarDecl i t e) = print t ++ [" ":i:"=":print e] ++ [";"]
137 instance print FunDecl where
138 print _ = ["Function printing not yet implemented"]
140 instance print Type where
141 print (TupleType t1 t2) = ["(":print t1] ++ [", ":print t2] ++ [")"]
142 print (ListType t) = ["[":print t] ++ ["]"]
143 print (IdType s) = [s]
144 print IntType = ["Int"]
145 print BoolType = ["Bool"]
146 print CharType = ["Char"]
147 print VarType = ["var"]
149 instance print Expr where
150 print (VarExpr i Nothing) = [i]
151 print (VarExpr i (Just mf)) = [i, case mf of
152 FieldHd = ".hd"; FieldTl = ".tl"
153 FieldSnd = ".snd"; FieldFst = ".fst"]
154 print (Op2Expr e1 o e2) = print e1 ++ [case o of
155 BiPlus = "+"; BiMinus = "-"; BiTimes = "*"; BiDivide = "/"
156 BiMod = "%"; BiEquals = "="; BiLesser = "<"; BiGreater = ">"
157 BiLesserEq = "<="; BiGreaterEq = ">="; BiUnEqual = "!=";
158 BiAnd = "&&"; BiOr = "||"; BiCons = ":"
160 print (Op1Expr o e) = [case o of
161 UnNegation = "!"; UnMinus = "-"
163 print (IntExpr i) = [toString i]
164 print (CharExpr c) = ["\'", case c of
165 '\b' = "\\b"; '\f' = "\\f"; '\n' = "\\n"
166 '\r' = "\\r"; '\t' = "\\t"; '\v' = "\\v"
167 c = if (c == toChar 7) "\\a" (toString c)
169 print (BoolExpr b) = [toString b]
170 print (FunExpr i es) = pe ++ flatten [[",":x]\\x<-tl pes]
171 where [pe:pes] = map print es
172 print EmptyListExpr = ["[]"]
173 print (TupleExpr e1 e2) = ["(":print e1] ++ [",":print e2] ++ [")"]