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44 lines
1.2 KiB
44 lines
1.2 KiB
{
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module Presyntax.Lexer where
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import qualified Data.ByteString.Lazy as Lbs
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import qualified Data.Text.Encoding as T
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import Presyntax.Tokens
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}
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%wrapper "monad-bytestring"
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$alpha = [a-zA-Z]
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$digit = [0-9]
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tokens :-
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$white+ ;
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$alpha [$alpha $digit \_ \']* { yield TokVar }
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\= { always TokEqual }
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\: { always TokColon }
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\, { always TokComma }
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\* { always TokStar }
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".1" { always TokPi1 }
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".2" { always TokPi2 }
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\\ { always TokLambda }
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"->" { always TokArrow }
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\( { always TokOParen }
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\{ { always TokOBrace }
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\) { always TokCParen }
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\} { always TokCBrace }
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{
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alexEOF :: Alex Token
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alexEOF = do
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(AlexPn _ l c, _, _, _) <- alexGetInput
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pure $ Token TokEof l c
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yield k (AlexPn _ l c, _, s, _) i = pure (Token (k $! (T.decodeUtf8 (Lbs.toStrict (Lbs.take i s)))) l c)
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always k x i = yield (const k) x i
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}
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