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 (parseAssStmt <* satTok SColonToken) <|>
43 (parseReturnStmt <* satTok SColonToken) <|>
44 (parseFunCall <* satTok SColonToken >>= \fc->pure $ FunStmt fc)
46 parseReturnStmt :: Parser Token Stmt
47 parseReturnStmt = satTok ReturnToken
48 *> optional parseExpr >>= \me->pure $ ReturnStmt me
50 parseAssStmt :: Parser Token Stmt
51 parseAssStmt = parseVarDef <* satTok AssignmentToken
52 >>= \var-> parseExpr >>= \expr->pure $ AssStmt var expr
54 parseIfStmt :: Parser Token Stmt
55 parseIfStmt = satTok IfToken
56 *> parseBBraces parseExpr
57 >>= \pred->parseBCBraces (many parseStmt)
58 >>= \thens->optional (
59 satTok ElseToken *> parseBCBraces (many parseStmt)
60 )>>= \elses->pure $ IfStmt pred thens (fromMaybe [] elses)
62 parseWhileStmt :: Parser Token Stmt
63 parseWhileStmt = satTok WhileToken *> parseBBraces parseExpr
64 >>= \pred->parseBCBraces (many parseStmt)
65 >>= \body->pure $ WhileStmt pred body
67 parseBBraces :: (Parser Token a) -> Parser Token a
68 parseBBraces p = satTok BraceOpenToken *> p <* satTok BraceCloseToken
70 parseBCBraces :: (Parser Token a) -> Parser Token a
71 parseBCBraces p = satTok CBraceOpenToken *> p <* satTok CBraceCloseToken
73 parseFunType :: Parser Token FunType
74 parseFunType = satTok DoubleColonToken *>
75 (parseInOutType <|> (parseVoidOrType >>= \t->pure $ FunType [] t))
77 parseInOutType :: Parser Token FunType
78 parseInOutType = some parseType <* satTok ArrowToken
79 >>= \intypes-> parseVoidOrType
80 >>= \outtypes->pure $ FunType intypes outtypes
82 parseVoidOrType :: Parser Token (Maybe Type)
83 parseVoidOrType = (satTok VoidToken *> pure Nothing) <|>
84 (parseType >>= \type->pure $ Just type)
86 parseVarDecl :: Parser Token VarDecl
88 (parseType <|> trans1 VarToken VarType )
89 >>= \t->parseIdent <* satTok AssignmentToken
90 >>= \i->parseExpr <* satTok SColonToken
91 >>= \e->pure $ VarDecl i t e
93 parseType :: Parser Token Type
95 trans1 IntTypeToken IntType <|>
96 trans1 CharTypeToken CharType <|>
97 trans1 BoolTypeToken BoolType <|>
98 (satTok SquareOpenToken *> parseType <* satTok SquareCloseToken
99 >>= \t.pure $ ListType t) <|>
100 (satTok BraceOpenToken *> parseType <* satTok CommaToken
101 >>= \t1->parseType <* satTok BraceCloseToken
102 >>= \t2->pure $ TupleType t1 t2) <|>
103 (parseIdent >>= \e.pure $ IdType e) <|>
106 parseExpr :: Parser Token Expr
107 parseExpr = //Operators in order of binding strength
108 parseOpR (trans1 ColonToken BiCons) $
109 parseOpR (trans1 PipesToken BiOr) $
110 parseOpR (trans1 AmpersandsToken BiAnd) $
111 parseOpR (trans1 EqualsToken BiEquals <|>
112 trans1 LesserToken BiLesser <|>
113 trans1 BiggerToken BiGreater <|>
114 trans1 LesserEqToken BiLesserEq <|>
115 trans1 GreaterEqToken BiGreaterEq <|>
116 trans1 NotEqualToken BiUnEqual) $
117 parseOpL (trans1 PlusToken BiPlus <|>
118 trans1 DashToken BiMinus) $
119 parseOpL (trans1 StarToken BiTimes <|>
120 trans1 SlashToken BiDivide <|>
121 trans1 PercentToken BiMod) $ parseBasicExpr
123 parseOpR :: (Parser Token Op2) (Parser Token Expr) -> Parser Token Expr
124 parseOpR ops prev = prev >>= \e1->optional (
125 ops >>= \op->parseOpR ops prev >>= \e->pure (op, e)
126 ) >>= \moe->pure $ maybe e1 (\(op,e2)->Op2Expr e1 op e2) moe
128 parseOpL :: (Parser Token Op2) (Parser Token Expr) -> Parser Token Expr
129 parseOpL ops prev = prev >>= \e1->many (
130 ops >>= \op->prev >>= \e->pure (op, e)
131 ) >>= \moe->foldM (\e->(\(op,e2)->pure $ Op2Expr e op e2)) e1 moe
133 parseBasicExpr :: Parser Token Expr
135 (satTok BraceOpenToken *> parseExpr <* satTok CommaToken
136 >>= \e1->parseExpr <* satTok BraceCloseToken
137 >>= \e2->pure $ TupleExpr e1 e2) <|>
138 (parseFunCall >>= \fc->pure $ FunExpr fc) <|>
139 parseBBraces parseExpr <|>
140 trans1 EmptyListToken EmptyListExpr <|>
141 trans2 TrueToken (const $ BoolExpr True) <|>
142 trans2 FalseToken (const $ BoolExpr False) <|>
143 trans2 (NumberToken zero) (\(NumberToken i)->IntExpr i) <|>
144 trans2 (CharToken zero) (\(CharToken c)->CharExpr c) <|>
145 (parseOp1 >>= \o->parseExpr >>= \e.pure $ Op1Expr o e) <|>
146 (parseVarDef >>= \ve->pure $ VarExpr ve)
148 parseFunCall :: Parser Token FunCall
149 parseFunCall = parseIdent <* satTok BraceOpenToken
150 >>= \i->parseSepList CommaToken parseExpr
151 <* satTok BraceCloseToken >>= \es->pure $ FunCall i es
153 parseVarDef :: Parser Token VarDef
154 parseVarDef = parseIdent
155 >>= \i-> many (satTok DotToken *> (
156 (parseIdent >>= (\i.if (i == "hd") (pure FieldHd) empty)) <|>
157 (parseIdent >>= \i.if (i == "tl") (pure FieldTl) empty) <|>
158 (parseIdent >>= \i.if (i == "fst") (pure FieldFst) empty) <|>
159 (parseIdent >>= \i.if (i == "snd") (pure FieldSnd) empty))
160 ) >>= \f->pure $ VarDef i f
162 parseOp1 :: Parser Token Op1
163 parseOp1 = trans1 DashToken UnMinus <|>
164 trans1 ExclamationToken UnNegation
166 trans2 :: TokenValue (TokenValue -> a) -> Parser Token a
167 trans2 t f = satTok t >>= \(_, r).pure (f r)
169 trans1 :: TokenValue a -> Parser Token a
170 trans1 t r = trans2 t $ const r
172 satTok :: TokenValue -> Parser Token Token
173 satTok t = satisfy ((===) t)
175 parseSepList :: TokenValue (Parser Token a) -> Parser Token [a]
177 (some (p <* satTok sep) >>= \es->p >>= \e.pure $ reverse [e:es]) <|>
178 (p >>= \e->pure [e]) <|> pure []
180 parseIdent :: Parser Token String
181 parseIdent = trans2 (IdentToken []) (\(IdentToken e).toString e)
183 instance toString AST where
184 toString (AST v f) = concat (
185 ["\n":printersperse "\n" v] ++
186 ["\n":printersperse "\n" f])
188 class print a :: a -> [String]
190 printersperse :: String [a] -> [String] | print a
191 printersperse i j = intercalate [i] (map print j)
193 instance print FunDecl where
194 print (FunDecl i as t vs ss) =
195 ["\n", i, " (":printersperse "," as] ++
197 ["{\n\t":printersperse "\n\t" vs] ++
198 ["\n":printStatements ss 1] ++ ["\n}"]
200 printStatements :: [Stmt] Int -> [String]
201 printStatements [] i = []
202 printStatements [s:ss] i = (case s of
203 (IfStmt b thens elses) = indent i ["if (":print b] ++ ["){\n"] ++
204 printStatements thens (i+1) ++
205 indent i ["} else {\n":printStatements elses (i+1)] ++
207 (WhileStmt b dos) = indent i ["while (":print b] ++
208 ["){\n":printStatements dos (i+1)] ++ indent i ["}\n"]
209 (AssStmt vardef val) =
210 indent i $ print vardef ++ ["=":print val] ++ [";\n"]
211 (FunStmt fc) = indent i $ print fc ++ [";\n"]
212 (ReturnStmt me) = indent i ["return ":maybe [""] print me] ++ [";\n"]
213 ) ++ printStatements ss i
215 indent :: Int [String] -> [String]
216 indent i rest = replicate i "\t" ++ rest
218 instance print FunType where
219 print (FunType at rt) = printersperse " " at ++
220 [if (isEmpty at) "" "->":maybe ["Void"] print rt]
222 instance print VarDecl where
223 print (VarDecl i t e) = print t ++ [" ":i:"=":print e] ++ [";"]
225 instance print Type where
226 print (TupleType t1 t2) = ["(":print t1] ++ [",":print t2] ++ [")"]
227 print (ListType t) = ["[":print t] ++ ["]"]
228 print (IdType s) = print s
229 print IntType = print "Int"
230 print BoolType = print "Bool"
231 print CharType = print "Char"
232 print VarType = print "var"
234 instance print String where
237 instance print FieldSelector where
238 print FieldHd = print "hd"
239 print FieldTl = print "tl"
240 print FieldSnd = print "snd"
241 print FieldFst = print "fst"
243 instance print VarDef where
244 print (VarDef i fs) = printersperse "." [i:flatten $ map print fs]
246 instance print FunCall where
247 print (FunCall i args) = [i,"(":printersperse "," args] ++ [")"]
249 instance print Expr where
250 print (VarExpr vd) = print vd
251 print (Op2Expr e1 o e2) = ["(":print e1] ++ [" ",case o of
252 BiPlus = "+"; BiMinus = "-"; BiTimes = "*"; BiDivide = "/"
253 BiMod = "%"; BiEquals = "="; BiLesser = "<"; BiGreater = ">"
254 BiLesserEq = "<="; BiGreaterEq = ">="; BiUnEqual = "!=";
255 BiAnd = "&&"; BiOr = "||"; BiCons = ":"
256 ," ":print e2] ++ [")"]
257 print (Op1Expr o e) = ["(",case o of
258 UnNegation = "!"; UnMinus = "-"
260 print (IntExpr i) = [toString i]
261 print (CharExpr c) = ["\'", case c of
262 '\b' = "\\b"; '\f' = "\\f"; '\n' = "\\n"
263 '\r' = "\\r"; '\t' = "\\t"; '\v' = "\\v"
264 c = if (c == toChar 7) "\\a" (toString c)
266 print (BoolExpr b) = [toString b]
267 print (FunExpr fc) = print fc
268 print EmptyListExpr = ["[]"]
269 print (TupleExpr e1 e2) = ["(":print e1] ++ [",":print e2] ++ [")"]