lexer

lib/Quox/CharExtra.idr

@@ -1,4 +1,4 @@
-module Quox.Unicode
+module Quox.CharExtra
 
 import Generics.Derive
 
@@ -123,11 +123,13 @@ namespace Char
 
 export
 isIdStart : Char -> Bool
-isIdStart ch = isLetter ch || isNumber ch && not ('0' <= ch && ch <= '9')
+isIdStart ch =
+  ch == '_' || isLetter ch || isNumber ch && not ('0' <= ch && ch <= '9')
 
 export
 isIdCont : Char -> Bool
-isIdCont ch = isIdStart ch || ch == '\'' || isMark ch || isNumber ch
+isIdCont ch =
+  isIdStart ch || ch == '\'' || isMark ch || isNumber ch
 
 export
 isIdConnector : Char -> Bool
@@ -136,12 +138,11 @@ isIdConnector ch = genCat ch == Punctuation Connector
 
 export
 isSymChar : Char -> Bool
-isSymChar ch =
-  case genCat ch of
-    Symbol      _     => True
-    Punctuation Dash  => True
-    Punctuation Other => True
-    _                 => False
+isSymChar ch = case genCat ch of
+  Symbol      _     => True
+  Punctuation Dash  => True
+  Punctuation Other => True
+  _                 => False
 
 export
 isWhitespace : Char -> Bool

lib/Quox/Lexer.idr

@@ -0,0 +1,183 @@
+module Quox.Lexer
+
+import Quox.CharExtra
+import Quox.Name
+import Data.String.Extra
+import Data.SortedMap
+import Text.Lexer
+import Text.Lexer.Tokenizer
+import Generics.Derive
+%hide TT.Name
+
+
+%default total
+%language ElabReflection
+
+
+||| @ R reserved token
+||| @ I identifier
+||| @ N nat literal
+||| @ S string literal
+||| @ T tag literal
+||| @ TYPE "Type" or "★" with subscript
+public export
+data Token = R String | I Name | N Nat | S String | T String | TYPE Nat
+%runElab derive "Token" [Generic, Meta, Eq, Ord, DecEq, Show]
+
+-- token or whitespace
+private
+0 TokenW : Type
+TokenW = Maybe Token
+
+
+public export
+record Error where
+  constructor Err
+  reason    : StopReason
+  line, col : Int
+  ||| `Nothing` if the error is at the end of the input
+  char      : Maybe Char
+%runElab derive "StopReason" [Generic, Meta, Eq, Ord, DecEq, Show]
+%runElab derive "Error"      [Generic, Meta, Eq, Ord, DecEq, Show]
+
+
+skip : Lexer -> Tokenizer TokenW
+skip t = match t $ const Nothing
+
+export
+syntaxChars : List Char
+syntaxChars = ['(', ')', '[', ']', '{', '}', '`', '"', '\'', ',', '.']
+
+export
+isSymStart, isSymCont : Char -> Bool
+isSymStart c = not (c `elem` syntaxChars) && isSymChar c
+isSymCont  c = c == '\'' || isSymStart c
+
+export
+idStart, idCont, idEnd, idContEnd, symStart, symCont : Lexer
+idStart   = pred isIdStart
+idCont    = pred isIdCont
+idEnd     = pred $ \c => c `elem` unpack "?!#"
+idContEnd = idCont <|> idEnd
+symStart  = pred isSymStart
+symCont   = pred isSymCont
+
+private %inline
+resVal : String -> a -> Maybe Token
+resVal str = const $ Just $ R str
+
+export
+resWordL, resSymL, syntaxL : String -> Lexer
+resWordL str = exact str <+> reject idContEnd
+resSymL  str = exact str <+> reject symCont
+syntaxL  str = exact str
+
+export
+resWord, resSym, syntax : String -> Tokenizer TokenW
+resWord str = match (resWordL str) (resVal str)
+resSym  str = match (resSymL  str) (resVal str)
+syntax  str = match (syntaxL  str) (resVal str)
+
+-- return value contains unicode version
+export
+uresWord, uresSym, usyntax : (unicode, ascii : String) -> Tokenizer TokenW
+uresWord u a = match (resWordL u <|> resWordL a) (resVal u)
+uresSym  u a = match (resSymL u <|> resSymL a) (resVal u)
+usyntax  u a = match (exact u <|> exact a) (resVal u)
+
+export
+alphaName, symName, baseNameL : Lexer
+alphaName = idStart <+> many idCont <+> many idEnd
+symName   = symStart <+> many symCont
+baseNameL = symName <|> alphaName
+
+export
+baseName : Tokenizer BaseName
+baseName = match baseNameL UN
+
+private
+toName : String -> Name
+toName = fromList . split (== '.')
+
+export
+name : Tokenizer TokenW
+name = match (baseNameL <+> many (is '.' <+> baseNameL))
+             (Just . I . toName . normalizeNfc)
+
+-- [todo] escapes other than \" and (accidentally) \\
+export
+fromStringLit : String -> String
+fromStringLit = pack . go . unpack . drop 1 . dropLast 1 where
+  go : List Char -> List Char
+  go []                = []
+  go ['\\']            = ['\\'] -- i guess???
+  go ('\\' :: c :: cs) = c :: go cs
+  go (c :: cs)         = c :: go cs
+
+export
+string : Tokenizer TokenW
+string = match stringLit (Just . S . fromStringLit)
+
+export
+nat : Tokenizer TokenW
+nat = match (some (range '0' '9')) (Just . N . cast)
+
+export
+tag : Tokenizer TokenW
+tag = match (is '`' <+> baseNameL) (Just . T . drop 1)
+  <|> match (is '`' <+> stringLit) (Just . T . fromStringLit . drop 1)
+
+
+
+private %inline
+fromSub : Char -> Char
+fromSub c = case c of
+  '₀' => '0'; '₁' => '1'; '₂' => '2'; '₃' => '3'; '₄' => '4'
+  '₅' => '5'; '₆' => '6'; '₇' => '7'; '₈' => '8'; '₉' => '9'; _ => c
+
+private %inline
+subToNat : String -> Nat
+subToNat = cast . pack . map fromSub . unpack
+
+
+export
+universe : Tokenizer TokenW
+universe = universeWith "★" <|> universeWith "Type" where
+  universeWith : String -> Tokenizer TokenW
+  universeWith pfx =
+    let len = length pfx in
+    match (exact pfx <+> some (range '0' '9'))
+          (Just . TYPE . cast . drop len) <|>
+    match (exact pfx <+> some (range '₀' '₉'))
+          (Just . TYPE . subToNat . drop len)
+
+
+export
+choice : (xs : List (Tokenizer a)) -> (0 _ : NonEmpty xs) => Tokenizer a
+choice (t :: ts) = foldl (\a, b => a <|> b) t ts
+
+
+export
+tokens : Tokenizer TokenW
+tokens = choice $
+  map skip [pred isWhitespace,
+            lineComment (exact "--" <+> reject symCont),
+            blockComment (exact "{-") (exact "-}")] <+>
+  map syntax ["(", ")", "[", "]", ",", "{", "}", "."] <+>
+  [match (exact "`{" <+> reject (is '-')) (resVal "`{")] <+>
+  map resSym ["@", ":"] <+>
+  map (uncurry uresSym)
+    [("·", "%"), ("→","->"), ("×", "**"), ("≡", "=="), ("∷", "::")] <+>
+  map resWord ["case", "case1", "caseω", "return", "of", "_"] <+>
+  map (uncurry uresWord) [("λ","fun"), ("δ","dfun"), ("caseω", "case#")] <+>
+  [resWord "ω", match (resSymL "#") (resVal "ω"),
+   universe, resSym "★", match (resWordL "Type") (resVal "★")] <+>
+  [nat, string, tag, name]
+
+export
+lex : String -> Either Error (List (WithBounds Token))
+lex str =
+  let (res, reason, line, col, str) = lex tokens str in
+  case reason of
+    EndInput => Right $ mapMaybe sequence res
+    _        => Left  $ Err {reason, line, col, char = index 0 str}

lib/Quox/Name.idr

@@ -34,7 +34,7 @@ record Name where
   constructor MakeName
   mods : SnocList String
   base : BaseName
-%runElab derive "Name" [Generic, Meta, Eq, Ord]
+%runElab derive "Name" [Generic, Meta, Eq, Ord, DecEq]
 
 export
 Show Name where
@@ -53,3 +53,10 @@ unq = MakeName [<]
 export
 toDots : Name -> String
 toDots x = fastConcat $ cast $ map (<+> ".") x.mods :< baseStr x.base
+
+export
+fromList : List1 String -> Name
+fromList (x ::: xs) = go [<] x xs where
+  go : SnocList String -> String -> List String -> Name
+  go mods x []        = MakeName mods (UN x)
+  go mods x (y :: ys) = go (mods :< x) y ys