78 lines
1.6 KiB
Haskell
78 lines
1.6 KiB
Haskell
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module Lexer where
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import Research
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import Text.Megaparsec
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import Text.Megaparsec.Char
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import Data.Void
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type Lexer = Parsec Void String
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data LToken
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= LKeywordT
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| LIdentifier String
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| LIntegerLiteral Int
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| LStringLiteral String
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| LAssign
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| LOpenParen
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| LCloseParen
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| LOpenBracket
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| LCloseBracket
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| LNewline
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deriving (Show, Eq, Ord)
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keywordT :: Lexer LToken
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keywordT = string "t" *> notFollowedBy alphaNumChar *> pure LKeywordT
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identifier :: Lexer LToken
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identifier = do
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name <- some (letterChar <|> char '_' <|> char '-')
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if name == "t"
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then fail "Keyword 't' cannot be used as an identifier"
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else return (LIdentifier name)
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integerLiteral :: Lexer LToken
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integerLiteral = do
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num <- some digitChar
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return (LIntegerLiteral (read num))
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stringLiteral :: Lexer LToken
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stringLiteral = do
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char '"'
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content <- many (noneOf ['"'])
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char '"' --"
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return (LStringLiteral content)
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assign :: Lexer LToken
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assign = char '=' *> pure LAssign
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openParen :: Lexer LToken
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openParen = char '(' *> pure LOpenParen
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closeParen :: Lexer LToken
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closeParen = char ')' *> pure LCloseParen
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openBracket :: Lexer LToken
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openBracket = char '[' *> pure LOpenBracket
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closeBracket :: Lexer LToken
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closeBracket = char ']' *> pure LCloseBracket
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lnewline :: Lexer LToken
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lnewline = char '\n' *> pure LNewline
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sc :: Lexer ()
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sc = skipMany (char ' ' <|> char '\t')
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saplingLexer :: Lexer [LToken]
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saplingLexer = many (sc *> choice
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[ try keywordT
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, try identifier
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, try integerLiteral
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, try stringLiteral
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, assign
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, openParen
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, closeParen
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, openBracket
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, closeBracket
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, lnewline
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]) <* eof
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