1 implementation module parse
6 from StdFunc import const, o
10 import Control.Applicative
12 from Data.List import intercalate, replicate, instance Functor []
13 from Text import class Text(concat), instance Text String
19 parser :: LexerOutput -> ParserOutput
20 parser (Left e) = Left e
21 parser (Right r) = fst $ runParser parseProgram r
23 parseProgram :: Parser Token AST
24 parseProgram = liftM2 AST (many parseVarDecl) (some parseFunDecl)
26 parseFunDecl :: Parser Token FunDecl
27 parseFunDecl = liftM5 FunDecl
28 (parseIdent <* satTok BraceOpenToken)
29 (parseSepList CommaToken parseIdent <* satTok BraceCloseToken)
30 (optional parseFunType <* satTok CBraceOpenToken)
32 (many parseStmt <* satTok CBraceCloseToken)
34 parseStmt :: Parser Token Stmt
35 parseStmt = parseIfStmt <|> parseWhileStmt <|>
36 parseSColon parseAssStmt <|> parseSColon parseReturnStmt <|>
37 (liftM FunStmt (parseSColon parseFunCall))
39 parseSColon :: (Parser Token a) -> Parser Token a
40 parseSColon p = p <* satTok SColonToken
42 parseReturnStmt :: Parser Token Stmt
44 satTok ReturnToken *> liftM ReturnStmt (optional parseExpr)
46 parseAssStmt :: Parser Token Stmt
48 liftM2 AssStmt (parseVarDef <* satTok AssignmentToken) parseExpr
50 parseIfStmt :: Parser Token Stmt
51 parseIfStmt = liftM3 IfStmt
52 (satTok IfToken *> parseBBraces parseExpr)
53 (parseBlock <|> parseOneLine)
55 (optional (satTok ElseToken *> (parseBlock<|> parseOneLine))))
57 parseWhileStmt :: Parser Token Stmt
58 parseWhileStmt = satTok WhileToken *>
59 liftM2 WhileStmt (parseBBraces parseExpr) parseBlock
61 parseBlock :: Parser Token [Stmt]
62 parseBlock = parseBCBraces (many parseStmt)
64 parseOneLine :: Parser Token [Stmt]
65 //first pure makes singleton list from the statement
66 parseOneLine = liftM pure parseStmt
68 parseFunType :: Parser Token FunType
69 parseFunType = satTok DoubleColonToken *>
70 (parseInOutType <|> (liftM (FunType []) parseVoidOrType))
72 parseInOutType :: Parser Token FunType
73 parseInOutType = liftM2 FunType
74 (some parseType <* satTok ArrowToken) parseVoidOrType
76 parseVoidOrType :: Parser Token (Maybe Type)
77 parseVoidOrType = (satTok VoidToken *> pure Nothing) <|>
78 (liftM Just parseType) <|> pure Nothing
80 parseVarDecl :: Parser Token VarDecl
81 parseVarDecl = liftM3 VarDecl
82 (parseType <|> trans1 VarToken VarType )
83 (parseIdent <* satTok AssignmentToken)
84 (parseExpr <* satTok SColonToken)
86 parseType :: Parser Token Type
88 trans1 IntTypeToken IntType <|>
89 trans1 CharTypeToken CharType <|>
90 trans1 BoolTypeToken BoolType <|>
91 (liftM ListType (parseBSqBraces parseType)) <|>
92 (liftM TupleType (parseTuple parseType)) <|>
93 (liftM IdType parseIdent)
95 parseExpr :: Parser Token Expr
96 parseExpr = //Operators in order of binding strength
97 parseOpR (trans1 ColonToken BiCons) $
98 parseOpR (trans1 PipesToken BiOr) $
99 parseOpR (trans1 AmpersandsToken BiAnd) $
100 parseOpR (trans1 EqualsToken BiEquals <|>
101 trans1 LesserToken BiLesser <|>
102 trans1 BiggerToken BiGreater <|>
103 trans1 LesserEqToken BiLesserEq <|>
104 trans1 GreaterEqToken BiGreaterEq <|>
105 trans1 NotEqualToken BiUnEqual) $
106 parseOpL (trans1 PlusToken BiPlus <|>
107 trans1 DashToken BiMinus) $
108 parseOpL (trans1 StarToken BiTimes <|>
109 trans1 SlashToken BiDivide <|>
110 trans1 PercentToken BiMod) $ parseBasicExpr
112 parseOpR :: (Parser Token Op2) (Parser Token Expr) -> Parser Token Expr
113 parseOpR ops prev = prev >>= \e1->optional (
114 ops >>= \op->parseOpR ops prev >>= \e->pure (op, e)
115 ) >>= \moe->pure $ maybe e1 (\(op,e2)->Op2Expr e1 op e2) moe
117 parseOpL :: (Parser Token Op2) (Parser Token Expr) -> Parser Token Expr
118 parseOpL ops prev = prev >>= \e1->many (
119 ops >>= \op->prev >>= \e->pure (op, e)
120 ) >>= \moe->foldM (\e->(\(op,e2)->pure $ Op2Expr e op e2)) e1 moe
122 parseBasicExpr :: Parser Token Expr
124 (liftM TupleExpr (parseTuple parseExpr)) <|>
125 (liftM FunExpr parseFunCall) <|>
126 parseBBraces parseExpr <|>
127 trans1 EmptyListToken EmptyListExpr <|>
128 trans1 TrueToken (BoolExpr True) <|>
129 trans1 FalseToken (BoolExpr False) <|>
130 trans2 (NumberToken zero) (\(NumberToken i)->IntExpr i) <|>
131 trans2 (CharToken zero) (\(CharToken c)->CharExpr c) <|>
132 (liftM2 Op1Expr parseOp1 parseExpr) <|>
133 (liftM VarExpr parseVarDef)
135 parseFunCall :: Parser Token FunCall
136 parseFunCall = liftM2 FunCall
137 parseIdent (parseBBraces $ parseSepList CommaToken parseExpr)
139 parseVarDef :: Parser Token VarDef
140 parseVarDef = liftM2 VarDef
142 (many (satTok DotToken *> (
143 (parseIdent >>= (\i.if (i == "hd") (pure FieldHd) empty)) <|>
144 (parseIdent >>= \i.if (i == "tl") (pure FieldTl) empty) <|>
145 (parseIdent >>= \i.if (i == "fst") (pure FieldFst) empty) <|>
146 (parseIdent >>= \i.if (i == "snd") (pure FieldSnd) empty))))
148 parseOp1 :: Parser Token Op1
149 parseOp1 = trans1 DashToken UnMinus <|> trans1 ExclamationToken UnNegation
151 parseBBraces :: (Parser Token a) -> Parser Token a
152 parseBBraces p = satTok BraceOpenToken *> p <* satTok BraceCloseToken
154 parseBCBraces :: (Parser Token a) -> Parser Token a
155 parseBCBraces p = satTok CBraceOpenToken *> p <* satTok CBraceCloseToken
157 parseBSqBraces :: (Parser Token a) -> Parser Token a
158 parseBSqBraces p = satTok SquareOpenToken *> p <* satTok SquareCloseToken
160 parseTuple :: (Parser Token a) -> Parser Token (a, a)
161 parseTuple p = satTok BraceOpenToken *>
162 (liftM2 (\a->(\b->(a,b))) (p <* satTok CommaToken) p)
163 <* satTok BraceCloseToken
165 trans2 :: TokenValue (TokenValue -> a) -> Parser Token a
166 trans2 t f = liftM (\{token}->f token) $ satTok t
168 trans1 :: TokenValue a -> Parser Token a
169 trans1 t r = trans2 t $ const r
171 derive gPrint TokenValue
172 derive gEq TokenValue
173 satTok :: TokenValue -> Parser Token Token
174 satTok t = top >>= \tok=:{line,column,token} -> if (eq t token)
175 (pure tok) (fail <?> PositionalError line column
176 ("ParseError: Unexpected token: " +++ printToString token))
178 eq (IdentToken _) (IdentToken _) = True
179 eq (NumberToken _) (NumberToken _) = True
180 eq (CharToken _) (CharToken _) = True
181 eq x y = gEq {|*|} x y
183 parseSepList :: TokenValue (Parser Token a) -> Parser Token [a]
185 (liftM2 (\es->(\e->reverse [e:es])) (some (p <* satTok sep)) p) <|>
186 (liftM pure p) <|> pure empty
188 parseIdent :: Parser Token String
189 parseIdent = trans2 (IdentToken "") (\(IdentToken e).toString e)
191 instance toString AST where
192 toString (AST v f) = concat (
193 ["\n":printersperse "\n" v] ++
194 ["\n":printersperse "\n" f])
196 class print a :: a -> [String]
198 printersperse :: String [a] -> [String] | print a
199 printersperse i j = intercalate [i] (map print j)
201 instance print FunDecl where
202 print (FunDecl i as t vs ss) =
203 ["\n", i, " (":printersperse "," as] ++
204 [")"] ++ maybe [] (\tt->[" :: ":print tt]) t ++
205 ["{\n\t":printersperse "\n\t" vs] ++
206 ["\n":printStatements ss 1] ++ ["}\n"]
208 printStatements :: [Stmt] Int -> [String]
209 printStatements [] i = []
210 printStatements [s:ss] i = (case s of
211 (IfStmt b thens elses) = indent i ["if (":print b] ++ [")"] ++
212 printCodeBlock thens i ++
213 indent i ["else ":printCodeBlock elses i] ++ ["\n"]
214 (WhileStmt b dos) = indent i ["while (":print b] ++
215 [")":printCodeBlock dos i]
216 (AssStmt vardef val) =
217 indent i $ print vardef ++ ["=":print val] ++ [";\n"]
218 (FunStmt fc) = indent i $ print fc ++ [";\n"]
219 (ReturnStmt me) = indent i ["return ":maybe [""] print me] ++ [";\n"]
220 ) ++ printStatements ss i
222 printCodeBlock :: [Stmt] Int -> [String]
223 printCodeBlock [] _ = ["{}\n"]
224 printCodeBlock [x] i = ["\n":printStatements [x] (i+1)]
226 ["{\n":printStatements x (i+1)] ++ indent i ["}\n"]
228 indent :: Int [String] -> [String]
229 indent i rest = replicate i "\t" ++ rest
231 instance print FunType where
232 print (FunType at rt) = printersperse " " at ++
233 [if (isEmpty at) "" "->":maybe ["Void"] print rt]
235 instance print VarDecl where
236 print (VarDecl t i e) = print t ++ [" ":i:"=":print e] ++ [";"]
238 instance print Type where
239 print (TupleType (t1, t2)) = ["(":print t1] ++ [",":print t2] ++ [")"]
240 print (ListType t) = ["[":print t] ++ ["]"]
241 print (IdType s) = print s
242 print IntType = print "Int"
243 print BoolType = print "Bool"
244 print CharType = print "Char"
245 print VarType = print "var"
247 instance print String where
250 instance print FieldSelector where
251 print FieldHd = print "hd"
252 print FieldTl = print "tl"
253 print FieldSnd = print "snd"
254 print FieldFst = print "fst"
256 instance print VarDef where
257 print (VarDef i fs) = printersperse "." [i:flatten $ map print fs]
259 instance print FunCall where
260 print (FunCall i args) = [i,"(":printersperse "," args] ++ [")"]
262 instance print Expr where
263 print (VarExpr vd) = print vd
264 print (Op2Expr e1 o e2) = ["(":print e1] ++ [" ",case o of
265 BiPlus = "+"; BiMinus = "-"; BiTimes = "*"; BiDivide = "/"
266 BiMod = "%"; BiEquals = "="; BiLesser = "<"; BiGreater = ">"
267 BiLesserEq = "<="; BiGreaterEq = ">="; BiUnEqual = "!=";
268 BiAnd = "&&"; BiOr = "||"; BiCons = ":"
269 ," ":print e2] ++ [")"]
270 print (Op1Expr o e) = ["(",case o of
271 UnNegation = "!"; UnMinus = "-"
273 print (IntExpr i) = [toString i]
274 print (CharExpr c) = ["\'", case c of
275 '\b' = "\\b"; '\f' = "\\f"; '\n' = "\\n"
276 '\r' = "\\r"; '\t' = "\\t"; '\v' = "\\v"
277 c = if (c == toChar 7) "\\a" (toString c)
279 print (BoolExpr b) = [toString b]
280 print (FunExpr fc) = print fc
281 print EmptyListExpr = ["[]"]
282 print (TupleExpr (e1, e2)) = ["(":print e1] ++ [",":print e2] ++ [")"]