parse.icl

   1 implementation module parse
   2
   3 import StdString
   4 import StdTuple
   5 import StdList
   6 from StdFunc import const, o
   7 import Data.Either
   8 import Data.Maybe
   9 import Data.Functor
  10 import Control.Monad
  11 import Control.Applicative
  12 import Data.Func
  13 from Data.List import intercalate, replicate, instance Functor []
  14 from Text import class Text(concat), instance Text String
  15 import GenPrint
  16
  17 import yard
  18 import lex
  19 import AST
  20
  21 parser :: LexerOutput -> ParserOutput
  22 parser (Left e) = Left e
  23 parser (Right r) = fst $ runParser parseProgram r
  24
  25 parseProgram :: Parser Token AST
  26 parseProgram = liftM2 AST (many parseVarDecl) (some parseFunDecl)
  27
  28 parseFunDecl :: Parser Token FunDecl
  29 parseFunDecl = liftM5 FunDecl
  30         (parseIdent <* satTok BraceOpenToken)
  31         (parseSepList CommaToken parseIdent <* satTok BraceCloseToken)
  32         (optional parseFunType <* satTok CBraceOpenToken)
  33         (many parseVarDecl)
  34         (many parseStmt <* satTok CBraceCloseToken)
  35
  36 parseStmt :: Parser Token Stmt
  37 parseStmt = parseIfStmt <|> parseWhileStmt <|>
  38         parseSColon parseAssStmt <|> parseSColon parseReturnStmt <|>
  39         (liftM FunStmt (parseSColon parseFunCall))
  40         where
  41                 parseSColon :: (Parser Token a) -> Parser Token a
  42                 parseSColon p = p <* satTok SColonToken
  43
  44                 parseReturnStmt :: Parser Token Stmt
  45                 parseReturnStmt =
  46                         satTok ReturnToken *> liftM ReturnStmt (optional parseExpr)
  47
  48                 parseAssStmt :: Parser Token Stmt
  49                 parseAssStmt =
  50                         AssStmt <$> (parseVarDef <* satTok AssignmentToken) <*> parseExpr
  51
  52                 parseIfStmt :: Parser Token Stmt
  53                 parseIfStmt = liftM3 IfStmt
  54             (satTok IfToken *> parseBBraces parseExpr)
  55             (parseBlock <|> parseOneLine)
  56             (liftM (fromMaybe [])
  57                 (optional (satTok ElseToken *> (parseBlock<|> parseOneLine))))
  58
  59                 parseWhileStmt :: Parser Token Stmt
  60                 parseWhileStmt = satTok WhileToken *>
  61                         (WhileStmt <$> (parseBBraces parseExpr) <*> parseBlock)
  62
  63                 parseBlock :: Parser Token [Stmt]
  64                 parseBlock = parseBCBraces (many parseStmt)
  65
  66                 parseOneLine :: Parser Token [Stmt]
  67                 //first pure makes singleton list from the statement
  68                 parseOneLine = pure <$> parseStmt
  69
  70 parseFunType :: Parser Token FunType
  71 parseFunType = satTok DoubleColonToken *>
  72         (parseInOutType <|> ((FunType []) <$> parseVoidOrType))
  73         where
  74                 parseInOutType :: Parser Token FunType
  75                 parseInOutType =  FunType <$> (some parseType <* satTok ArrowToken) <*> parseVoidOrType
  76
  77                 parseVoidOrType :: Parser Token (Maybe Type)
  78                 parseVoidOrType = (satTok VoidToken *> pure Nothing) <|>
  79                         (Just <$> parseType) <|> pure Nothing
  80
  81 parseVarDecl :: Parser Token VarDecl
  82 parseVarDecl = liftM3 VarDecl
  83         (parseType <|> trans1 VarToken VarType )
  84         (parseIdent <* satTok AssignmentToken)
  85         (parseExpr <* satTok SColonToken)
  86
  87 parseType :: Parser Token Type
  88 parseType =
  89         trans1 IntTypeToken IntType <|>
  90         trans1 CharTypeToken CharType <|>
  91         trans1 BoolTypeToken BoolType <|>
  92         (ListType <$> (parseBSqBraces parseType)) <|>
  93         (TupleType <$> (parseTuple parseType)) <|>
  94         (IdType <$> parseIdent)
  95
  96 parseExpr :: Parser Token Expr
  97 parseExpr = //Operators in order of binding strength
  98         parseOpR (trans1 ColonToken BiCons) $
  99         parseOpR (trans1 PipesToken BiOr) $
 100         parseOpR (trans1 AmpersandsToken BiAnd) $
 101         parseOpR (trans1 EqualsToken BiEquals <|>
 102                         trans1 LesserToken BiLesser <|>
 103                         trans1 BiggerToken BiGreater <|>
 104                         trans1 LesserEqToken BiLesserEq <|>
 105                         trans1 GreaterEqToken BiGreaterEq <|>
 106                         trans1 NotEqualToken BiUnEqual) $
 107         parseOpL (trans1 PlusToken BiPlus <|>
 108                         trans1 DashToken BiMinus) $
 109         parseOpL (trans1 StarToken BiTimes <|>
 110                         trans1 SlashToken BiDivide <|>
 111                         trans1 PercentToken BiMod) $ parseBasicExpr
 112         where
 113                 parseOpR :: (Parser Token Op2) (Parser Token Expr) -> Parser Token Expr
 114                 parseOpR ops prev = prev >>= \e1->optional (
 115                                 ops >>= \op->parseOpR ops prev >>= \e->pure (op, e)
 116                         ) >>= \moe->pure $ maybe e1 (\(op,e2)->Op2Expr e1 op e2) moe
 117
 118                 parseOpL :: (Parser Token Op2) (Parser Token Expr) -> Parser Token Expr
 119                 parseOpL ops prev = prev >>= \e1->many (
 120                                 ops >>= \op->prev >>= \e->pure (op, e)
 121                         ) >>= \moe->foldM (\e->(\(op,e2)->pure $ Op2Expr e op e2)) e1 moe
 122
 123                 parseBasicExpr :: Parser Token Expr
 124                 parseBasicExpr =
 125                         (TupleExpr <$> (parseTuple parseExpr)) <|>
 126                         (FunExpr <$> parseFunCall) <|>
 127                         parseBBraces parseExpr <|>
 128                         trans1 EmptyListToken EmptyListExpr <|>
 129                         trans1 TrueToken (BoolExpr True) <|>
 130                         trans1 FalseToken (BoolExpr False) <|>
 131                         trans2 (NumberToken zero) (\(NumberToken i)->IntExpr i) <|>
 132                         trans2 (CharToken zero) (\(CharToken c)->CharExpr c) <|>
 133                         (Op1Expr <$> parseOp1 <*> parseExpr) <|>
 134                         (VarExpr <$> parseVarDef)
 135
 136 parseFunCall :: Parser Token FunCall
 137 parseFunCall = FunCall <$> parseIdent <*> (parseBBraces $ parseSepList CommaToken parseExpr)
 138
 139 parseVarDef :: Parser Token VarDef
 140 parseVarDef = liftM2 VarDef
 141         parseIdent
 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))))
 147
 148 parseOp1 :: Parser Token Op1
 149 parseOp1 = trans1 DashToken UnMinus <|> trans1 ExclamationToken UnNegation
 150
 151 parseBBraces :: (Parser Token a) -> Parser Token a
 152 parseBBraces p = satTok BraceOpenToken *> p <* satTok BraceCloseToken
 153
 154 parseBCBraces :: (Parser Token a) -> Parser Token a
 155 parseBCBraces p = satTok CBraceOpenToken *> p <* satTok CBraceCloseToken
 156
 157 parseBSqBraces :: (Parser Token a) -> Parser Token a
 158 parseBSqBraces p = satTok SquareOpenToken *> p <* satTok SquareCloseToken
 159
 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
 164
 165 trans2 :: TokenValue (TokenValue -> a) -> Parser Token a
 166 trans2 t f = (\(_,token)->f token) <$> satTok t
 167
 168 trans1 :: TokenValue a -> Parser Token a
 169 trans1 t r = trans2 t $ const r
 170
 171 derive gPrint TokenValue
 172 derive gEq TokenValue
 173 satTok :: TokenValue -> Parser Token Token
 174 satTok t = top >>= \tok=:({line,col},token) -> if (eq t token)
 175         (pure tok) (fail <?> PositionalError line col
 176                 ("ParseError: Unexpected token: " +++ printToString token))
 177         where
 178                 eq (IdentToken _)  (IdentToken _) = True
 179                 eq (NumberToken _) (NumberToken _) = True
 180                 eq (CharToken _)   (CharToken _) = True
 181                 eq x y = gEq {|*|} x y
 182
 183 parseSepList :: TokenValue (Parser Token a) -> Parser Token [a]
 184 parseSepList sep p =
 185         (liftM2 (\es->(\e->reverse [e:es])) (some (p <* satTok sep)) p) <|>
 186         (liftM pure p) <|> pure empty
 187
 188 parseIdent :: Parser Token String
 189 parseIdent = trans2 (IdentToken "") (\(IdentToken e).toString e)