1 implementation module parse
6 from StdFunc import const
11 import Control.Applicative
13 from Data.List import intercalate, replicate
14 from Text import class Text(concat), instance Text String
19 parser :: LexerOutput -> ParserOutput
20 parser (Left e) = Left $ toString $ LexError e
21 parser (Right r) = case runParser parseProgram r of
22 (Right p, _) = Right p
23 (Left e, _) = Left $ toString e
25 parseProgram :: Parser Token AST
26 parseProgram = many parseVarDecl
27 >>= \vd->some parseFunDecl
28 >>= \fd->pure $ AST vd fd
30 parseFunDecl :: Parser Token FunDecl
31 parseFunDecl = parseIdent <* satTok BraceOpenToken
32 >>= \ident->parseSepList CommaToken parseIdent <* satTok BraceCloseToken
33 >>= \args->parseFunType <* satTok CBraceOpenToken
34 >>= \funtype->many parseVarDecl
35 >>= \vardecls->many parseStmt
36 <* satTok CBraceCloseToken
37 >>= \stmts->pure $ FunDecl ident args funtype vardecls stmts
39 parseStmt :: Parser Token Stmt
40 parseStmt = parseIfStmt <|>
42 parseSColon parseAssStmt <|>
43 parseSColon parseReturnStmt <|>
44 (parseSColon parseFunCall >>= \fc->pure $ FunStmt fc)
46 parseSColon :: (Parser Token a) -> Parser Token a
47 parseSColon p = p <* satTok SColonToken
49 parseReturnStmt :: Parser Token Stmt
50 parseReturnStmt = satTok ReturnToken
51 *> optional parseExpr >>= \me->pure $ ReturnStmt me
53 parseAssStmt :: Parser Token Stmt
54 parseAssStmt = parseVarDef <* satTok AssignmentToken
55 >>= \var-> parseExpr >>= \expr->pure $ AssStmt var expr
57 parseIfStmt :: Parser Token Stmt
58 parseIfStmt = satTok IfToken
59 *> parseBBraces parseExpr
60 >>= \pred->(parseBlock <|> parseOneLine)
61 >>= \thens->optional (
62 satTok ElseToken *> (parseBlock <|> parseOneLine)
63 )>>= \elses->pure $ IfStmt pred thens (fromMaybe [] elses)
65 parseWhileStmt :: Parser Token Stmt
66 parseWhileStmt = satTok WhileToken *> parseBBraces parseExpr
67 >>= \pred->parseBlock >>= \body->pure $ WhileStmt pred body
69 parseBlock :: Parser Token [Stmt]
70 parseBlock = parseBCBraces (many parseStmt)
72 parseOneLine :: Parser Token [Stmt]
73 parseOneLine = parseStmt >>= \s->pure [s]
75 parseBBraces :: (Parser Token a) -> Parser Token a
76 parseBBraces p = satTok BraceOpenToken *> p <* satTok BraceCloseToken
78 parseBCBraces :: (Parser Token a) -> Parser Token a
79 parseBCBraces p = satTok CBraceOpenToken *> p <* satTok CBraceCloseToken
81 parseFunType :: Parser Token FunType
82 parseFunType = satTok DoubleColonToken *>
83 (parseInOutType <|> (parseVoidOrType >>= \t->pure $ FunType [] t))
85 parseInOutType :: Parser Token FunType
86 parseInOutType = some parseType <* satTok ArrowToken
87 >>= \intypes-> parseVoidOrType
88 >>= \outtypes->pure $ FunType intypes outtypes
90 parseVoidOrType :: Parser Token (Maybe Type)
91 parseVoidOrType = (satTok VoidToken *> pure Nothing) <|>
92 (parseType >>= \type->pure $ Just type)
94 parseVarDecl :: Parser Token VarDecl
96 (parseType <|> trans1 VarToken VarType )
97 >>= \t->parseIdent <* satTok AssignmentToken
98 >>= \i->parseExpr <* satTok SColonToken
99 >>= \e->pure $ VarDecl i t e
101 parseType :: Parser Token Type
103 trans1 IntTypeToken IntType <|>
104 trans1 CharTypeToken CharType <|>
105 trans1 BoolTypeToken BoolType <|>
106 (satTok SquareOpenToken *> parseType <* satTok SquareCloseToken
107 >>= \t.pure $ ListType t) <|>
108 (satTok BraceOpenToken *> parseType <* satTok CommaToken
109 >>= \t1->parseType <* satTok BraceCloseToken
110 >>= \t2->pure $ TupleType t1 t2) <|>
111 (parseIdent >>= \e.pure $ IdType e) <|>
114 parseExpr :: Parser Token Expr
115 parseExpr = //Operators in order of binding strength
116 parseOpR (trans1 ColonToken BiCons) $
117 parseOpR (trans1 PipesToken BiOr) $
118 parseOpR (trans1 AmpersandsToken BiAnd) $
119 parseOpR (trans1 EqualsToken BiEquals <|>
120 trans1 LesserToken BiLesser <|>
121 trans1 BiggerToken BiGreater <|>
122 trans1 LesserEqToken BiLesserEq <|>
123 trans1 GreaterEqToken BiGreaterEq <|>
124 trans1 NotEqualToken BiUnEqual) $
125 parseOpL (trans1 PlusToken BiPlus <|>
126 trans1 DashToken BiMinus) $
127 parseOpL (trans1 StarToken BiTimes <|>
128 trans1 SlashToken BiDivide <|>
129 trans1 PercentToken BiMod) $ parseBasicExpr
131 parseOpR :: (Parser Token Op2) (Parser Token Expr) -> Parser Token Expr
132 parseOpR ops prev = prev >>= \e1->optional (
133 ops >>= \op->parseOpR ops prev >>= \e->pure (op, e)
134 ) >>= \moe->pure $ maybe e1 (\(op,e2)->Op2Expr e1 op e2) moe
136 parseOpL :: (Parser Token Op2) (Parser Token Expr) -> Parser Token Expr
137 parseOpL ops prev = prev >>= \e1->many (
138 ops >>= \op->prev >>= \e->pure (op, e)
139 ) >>= \moe->foldM (\e->(\(op,e2)->pure $ Op2Expr e op e2)) e1 moe
141 parseBasicExpr :: Parser Token Expr
143 (satTok BraceOpenToken *> parseExpr <* satTok CommaToken
144 >>= \e1->parseExpr <* satTok BraceCloseToken
145 >>= \e2->pure $ TupleExpr e1 e2) <|>
146 (parseFunCall >>= \fc->pure $ FunExpr fc) <|>
147 parseBBraces parseExpr <|>
148 trans1 EmptyListToken EmptyListExpr <|>
149 trans2 TrueToken (const $ BoolExpr True) <|>
150 trans2 FalseToken (const $ BoolExpr False) <|>
151 trans2 (NumberToken zero) (\(NumberToken i)->IntExpr i) <|>
152 trans2 (CharToken zero) (\(CharToken c)->CharExpr c) <|>
153 (parseOp1 >>= \o->parseExpr >>= \e.pure $ Op1Expr o e) <|>
154 (parseVarDef >>= \ve->pure $ VarExpr ve)
156 parseFunCall :: Parser Token FunCall
157 parseFunCall = parseIdent <* satTok BraceOpenToken
158 >>= \i->parseSepList CommaToken parseExpr
159 <* satTok BraceCloseToken >>= \es->pure $ FunCall i es
161 parseVarDef :: Parser Token VarDef
162 parseVarDef = parseIdent
163 >>= \i-> many (satTok DotToken *> (
164 (parseIdent >>= (\i.if (i == "hd") (pure FieldHd) empty)) <|>
165 (parseIdent >>= \i.if (i == "tl") (pure FieldTl) empty) <|>
166 (parseIdent >>= \i.if (i == "fst") (pure FieldFst) empty) <|>
167 (parseIdent >>= \i.if (i == "snd") (pure FieldSnd) empty))
168 ) >>= \f->pure $ VarDef i f
170 parseOp1 :: Parser Token Op1
171 parseOp1 = trans1 DashToken UnMinus <|>
172 trans1 ExclamationToken UnNegation
174 trans2 :: TokenValue (TokenValue -> a) -> Parser Token a
175 trans2 t f = satTok t >>= \(_, r).pure (f r)
177 trans1 :: TokenValue a -> Parser Token a
178 trans1 t r = trans2 t $ const r
180 satTok :: TokenValue -> Parser Token Token
181 satTok t = satisfy ((===) t)
183 parseSepList :: TokenValue (Parser Token a) -> Parser Token [a]
185 (some (p <* satTok sep) >>= \es->p >>= \e.pure $ reverse [e:es]) <|>
186 (p >>= \e->pure [e]) <|> pure []
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] ++
205 ["{":printersperse "\n\t" vs] ++
206 ["\n":printStatements ss 1] ++ ["}"]
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 [] _ = ["{}"]
224 printCodeBlock [x] i = ["\n":printStatements [x] (i+1)]
226 ["{\n":printStatements x (i+1)] ++ indent i ["}"]
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 i t 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] ++ [")"]