244 lines
6.6 KiB
Idris
244 lines
6.6 KiB
Idris
module Quox.Parser.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 public Data.String -- for singleton to reduce in IsReserved
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import public Data.List.Elem
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import public Text.Lexer
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import public 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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||| @ Reserved reserved token
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||| @ Name name, possibly qualified
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||| @ Nat nat literal
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||| @ String string literal
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||| @ Tag tag literal
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||| @ TYPE "Type" or "★" with ascii nat directly after
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||| @ Sup superscript or ^ number (displacement, or universe for ★)
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public export
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data Token =
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Reserved String
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| Name PName
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| Nat Nat
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| Str String
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| Tag String
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| TYPE Nat
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| Sup Nat
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%runElab derive "Token" [Eq, Ord, Show]
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-- token or whitespace
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public export
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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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private
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skip : Lexer -> Tokenizer TokenW
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skip t = match t $ const Nothing
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private
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match : Lexer -> (String -> Token) -> Tokenizer TokenW
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match t f = Tokenizer.match t (Just . f)
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%hide Tokenizer.match
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private
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name : Tokenizer TokenW
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name = match name $ Name . fromListP . split (== '.') . 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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private
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string : Tokenizer TokenW
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string = match stringLit (Str . fromStringLit)
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private
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nat : Tokenizer TokenW
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nat = match (some (range '0' '9')) (Nat . cast)
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private
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tag : Tokenizer TokenW
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tag = match (is '\'' <+> name) (Tag . drop 1)
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<|> match (is '\'' <+> stringLit) (Tag . 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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fromSup : Char -> Char
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fromSup 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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private %inline
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supToNat : String -> Nat
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supToNat = cast . pack . map fromSup . unpack
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-- ★0, Type0. base ★/Type is a Reserved
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private
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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 <+> digits) (TYPE . cast . drop len)
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private
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sup : Tokenizer TokenW
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sup = match (some $ pred isSupDigit) (Sup . supToNat)
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<|> match (is '^' <+> digits) (Sup . cast . drop 1)
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private %inline
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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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namespace Reserved
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||| description of a reserved symbol
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||| @ Word a reserved word (must not be followed by letters, digits, etc)
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||| @ Sym a reserved symbol (must not be followed by symbolic chars)
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||| @ Punc a character that doesn't show up in names (brackets, etc)
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public export
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data Reserved1 = Word String | Sym String | Punc Char
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%runElab derive "Reserved1" [Eq, Ord, Show]
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||| description of a token that might have unicode & ascii-only aliases
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public export
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data Reserved = Only Reserved1 | Or Reserved1 Reserved1
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%runElab derive "Reserved" [Eq, Ord, Show]
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public export
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Sym1, Word1 : String -> Reserved
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Sym1 = Only . Sym
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Word1 = Only . Word
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public export
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Punc1 : Char -> Reserved
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Punc1 = Only . Punc
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public export
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resString1 : Reserved1 -> String
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resString1 (Punc x) = singleton x
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resString1 (Word w) = w
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resString1 (Sym s) = s
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||| return the representative string for a token description. if there are
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||| two, then it's the first one, which should be the full-unicode one
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public export
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resString : Reserved -> String
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resString (Only r) = resString1 r
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resString (r `Or` _) = resString1 r
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private
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resTokenizer1 : Reserved1 -> String -> Tokenizer TokenW
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resTokenizer1 r str =
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let res : String -> Token := const $ Reserved str in
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case r of Word w => match (exact w <+> reject idContEnd) res
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Sym s => match (exact s <+> reject symCont) res
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Punc x => match (is x) res
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||| match a reserved token
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export
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resTokenizer : Reserved -> Tokenizer TokenW
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resTokenizer (Only r) = resTokenizer1 r (resString1 r)
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resTokenizer (r `Or` s) =
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resTokenizer1 r (resString1 r) <|> resTokenizer1 s (resString1 r)
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||| reserved words & symbols.
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||| the tokens recognised by ``a `Or` b`` will be `Reserved a`.
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||| e.g. `=>` in the input (if not part of a longer name)
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||| will be returned as `Reserved "⇒"`.
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public export
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reserved : List Reserved
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reserved =
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[Punc1 '(', Punc1 ')', Punc1 '[', Punc1 ']', Punc1 '{', Punc1 '}',
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Punc1 ',', Punc1 ';',
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Sym1 "@",
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Sym1 ":",
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Sym "⇒" `Or` Sym "=>",
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Sym "→" `Or` Sym "->",
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Sym "×" `Or` Sym "**",
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Sym "≡" `Or` Sym "==",
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Sym "∷" `Or` Sym "::",
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Punc1 '.',
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Word1 "case",
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Word1 "case0", Word1 "case1",
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Word "caseω" `Or` Word "case#",
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Word1 "return",
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Word1 "of",
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Word1 "_",
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Word1 "Eq",
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Word "λ" `Or` Word "fun",
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Word "δ" `Or` Word "dfun",
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Word "ω" `Or` Sym "#",
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Sym "★" `Or` Word "Type",
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Word "ℕ" `Or` Word "Nat",
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Word1 "zero", Word1 "succ",
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Word1 "coe", Word1 "comp",
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Word1 "def",
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Word1 "def0",
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Word "defω" `Or` Word "def#",
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Sym1 "=",
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Word1 "load",
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Word1 "namespace"]
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||| `IsReserved str` is true if `Reserved str` might actually show up in
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||| the token stream
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public export
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IsReserved : String -> Type
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IsReserved str = str `Elem` map resString reserved
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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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[universe] <+> -- ★ᵢ takes precedence over bare ★
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map resTokenizer reserved <+>
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[sup, 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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