184 lines
5.0 KiB
Idris
184 lines
5.0 KiB
Idris
module Quox.Lexer
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import Quox.CharExtra
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import Quox.Name
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import Data.String.Extra
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import Data.SortedMap
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import Text.Lexer
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import Text.Lexer.Tokenizer
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import Derive.Prelude
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%hide TT.Name
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%default total
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%language ElabReflection
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||| @ R reserved token
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||| @ I identifier
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||| @ N nat literal
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||| @ S string literal
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||| @ T tag literal
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||| @ TYPE "Type" or "★" with subscript
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public export
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data Token = R String | I Name | N Nat | S String | T String | TYPE Nat
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%runElab derive "Token" [Eq, Ord, Show]
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-- token or whitespace
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private
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0 TokenW : Type
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TokenW = Maybe Token
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public export
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record Error where
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constructor Err
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reason : StopReason
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line, col : Int
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||| `Nothing` if the error is at the end of the input
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char : Maybe Char
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%runElab derive "StopReason" [Eq, Ord, Show]
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%runElab derive "Error" [Eq, Ord, Show]
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skip : Lexer -> Tokenizer TokenW
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skip t = match t $ const Nothing
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export
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syntaxChars : List Char
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syntaxChars = ['(', ')', '[', ']', '{', '}', '`', '"', '\'', ',', '.']
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export
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isSymStart, isSymCont : Char -> Bool
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isSymStart c = not (c `elem` syntaxChars) && isSymChar c
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isSymCont c = c == '\'' || isSymStart c
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export
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idStart, idCont, idEnd, idContEnd, symStart, symCont : Lexer
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idStart = pred isIdStart
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idCont = pred isIdCont
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idEnd = pred $ \c => c `elem` unpack "?!#"
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idContEnd = idCont <|> idEnd
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symStart = pred isSymStart
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symCont = pred isSymCont
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private %inline
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resVal : String -> a -> Maybe Token
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resVal str = const $ Just $ R str
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export
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resWordL, resSymL, syntaxL : String -> Lexer
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resWordL str = exact str <+> reject idContEnd
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resSymL str = exact str <+> reject symCont
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syntaxL str = exact str
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export
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resWord, resSym, syntax : String -> Tokenizer TokenW
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resWord str = match (resWordL str) (resVal str)
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resSym str = match (resSymL str) (resVal str)
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syntax str = match (syntaxL str) (resVal str)
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-- return value contains unicode version
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export
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uresWord, uresSym, usyntax : (unicode, ascii : String) -> Tokenizer TokenW
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uresWord u a = match (resWordL u <|> resWordL a) (resVal u)
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uresSym u a = match (resSymL u <|> resSymL a) (resVal u)
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usyntax u a = match (exact u <|> exact a) (resVal u)
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export
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alphaName, symName, baseNameL : Lexer
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alphaName = idStart <+> many idCont <+> many idEnd
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symName = symStart <+> many symCont
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baseNameL = symName <|> alphaName
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export
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baseName : Tokenizer BaseName
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baseName = match baseNameL UN
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private
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toName : String -> Name
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toName = fromList . split (== '.')
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export
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name : Tokenizer TokenW
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name = match (baseNameL <+> many (is '.' <+> baseNameL))
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(Just . I . toName . normalizeNfc)
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-- [todo] escapes other than \" and (accidentally) \\
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export
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fromStringLit : String -> String
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fromStringLit = pack . go . unpack . drop 1 . dropLast 1 where
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go : List Char -> List Char
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go [] = []
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go ['\\'] = ['\\'] -- i guess???
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go ('\\' :: c :: cs) = c :: go cs
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go (c :: cs) = c :: go cs
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export
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string : Tokenizer TokenW
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string = match stringLit (Just . S . fromStringLit)
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export
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nat : Tokenizer TokenW
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nat = match (some (range '0' '9')) (Just . N . cast)
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export
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tag : Tokenizer TokenW
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tag = match (is '`' <+> baseNameL) (Just . T . drop 1)
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<|> match (is '`' <+> stringLit) (Just . T . fromStringLit . drop 1)
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private %inline
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fromSub : Char -> Char
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fromSub c = case c of
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'₀' => '0'; '₁' => '1'; '₂' => '2'; '₃' => '3'; '₄' => '4'
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'₅' => '5'; '₆' => '6'; '₇' => '7'; '₈' => '8'; '₉' => '9'; _ => c
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private %inline
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subToNat : String -> Nat
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subToNat = cast . pack . map fromSub . unpack
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export
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universe : Tokenizer TokenW
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universe = universeWith "★" <|> universeWith "Type" where
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universeWith : String -> Tokenizer TokenW
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universeWith pfx =
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let len = length pfx in
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match (exact pfx <+> some (range '0' '9'))
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(Just . TYPE . cast . drop len) <|>
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match (exact pfx <+> some (range '₀' '₉'))
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(Just . TYPE . subToNat . drop len)
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export
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choice : (xs : List (Tokenizer a)) -> (0 _ : NonEmpty xs) => Tokenizer a
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choice (t :: ts) = foldl (\a, b => a <|> b) t ts
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export
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tokens : Tokenizer TokenW
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tokens = choice $
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map skip [pred isWhitespace,
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lineComment (exact "--" <+> reject symCont),
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blockComment (exact "{-") (exact "-}")] <+>
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map syntax ["(", ")", "[", "]", ",", "{", "}", "."] <+>
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[match (exact "`{" <+> reject (is '-')) (resVal "`{")] <+>
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map resSym ["@", ":"] <+>
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map (uncurry uresSym)
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[("·", "%"), ("→","->"), ("×", "**"), ("≡", "=="), ("∷", "::")] <+>
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map resWord ["case", "case1", "caseω", "return", "of", "_"] <+>
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map (uncurry uresWord) [("λ","fun"), ("δ","dfun"), ("caseω", "case#")] <+>
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[resWord "ω", match (resSymL "#") (resVal "ω"),
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universe, resSym "★", match (resWordL "Type") (resVal "★")] <+>
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[nat, string, tag, name]
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export
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lex : String -> Either Error (List (WithBounds Token))
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lex str =
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let (res, reason, line, col, str) = lex tokens str in
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case reason of
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EndInput => Right $ mapMaybe sequence res
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_ => Left $ Err {reason, line, col, char = index 0 str}
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