Beginnings of Parsec parser.
Chris Pressey
6 months ago
| 0 | 0 | module Language.ZOWIE.Parser where |
| 1 | ||
| 2 | import Text.ParserCombinators.Parsec | |
| 1 | 3 | |
| 2 | 4 | import Language.ZOWIE.State |
| 3 | 5 | |
| 7 | 9 | splitLines ('\n':rest) line = [reverse line] ++ (splitLines rest []) |
| 8 | 10 | splitLines (char:rest) line = splitLines rest (char:line) |
| 9 | 11 | |
| 12 | -- | |
| 13 | -- The grammar of a line is | |
| 14 | -- | |
| 15 | -- Line ::= Comment | "MOV" Operand "," Operand [Comment]. | |
| 16 | -- Operand ::= "R[R" Number "]" | "R" Number | Number. | |
| 17 | -- Comment ::= ";" anything. | |
| 18 | -- | |
| 19 | ||
| 20 | zowieLine = commentLine <|> instrLine | |
| 21 | ||
| 22 | commentLine :: Parser (Maybe Instruction) | |
| 23 | commentLine = do | |
| 24 | spaces | |
| 25 | string ";" | |
| 26 | many $ satisfy (\x -> x /= '\n') | |
| 27 | return Nothing | |
| 28 | ||
| 29 | instrLine :: Parser (Maybe Instruction) | |
| 30 | instrLine = do | |
| 31 | spaces | |
| 32 | string "MOV" | |
| 33 | dest <- operand | |
| 34 | spaces | |
| 35 | string "," | |
| 36 | src <- operand | |
| 37 | optional commentLine | |
| 38 | return $ Just $ Mov dest src | |
| 39 | ||
| 40 | operand = do | |
| 41 | spaces | |
| 42 | r <- indirect <|> direct <|> immediate | |
| 43 | return r | |
| 44 | ||
| 45 | indirect = do | |
| 46 | string "R[R" | |
| 47 | n <- number | |
| 48 | string "]" | |
| 49 | return $ Indirect n | |
| 50 | ||
| 51 | direct = do | |
| 52 | string "R" | |
| 53 | n <- number | |
| 54 | return $ Direct n | |
| 55 | ||
| 56 | immediate = do | |
| 57 | n <- number | |
| 58 | return $ Direct n | |
| 59 | ||
| 60 | number = do | |
| 61 | c <- digit | |
| 62 | cs <- many digit | |
| 63 | num <- return (read (c:cs) :: Integer) | |
| 64 | return num | |
| 65 | ||
| 66 | ||
| 10 | 67 | parseLines [] = [] |
| 11 | 68 | parseLines (line:lines) = |
| 12 | case parseLine line of | |
| 13 | Just instr -> | |
| 14 | (instr:parseLines lines) | |
| 15 | Nothing -> | |
| 69 | case parse zowieLine "" line of | |
| 70 | Left err -> | |
| 16 | 71 | parseLines lines |
| 17 | ||
| 18 | parseLine [] = Nothing | |
| 19 | parseLine (' ':rest) = parseLine rest | |
| 20 | parseLine ('M':'O':'V':rest) = Just $ Mov (Direct 0) (Immediate 0) | |
| 21 | ||
| 72 | Right result -> | |
| 73 | case result of | |
| 74 | Just instr -> | |
| 75 | (instr:parseLines lines) | |
| 76 | Nothing -> | |
| 77 | parseLines lines | |
| 22 | 78 | |
| 23 | 79 | parseZOWIE text = |
| 24 | 80 | let |