add binary literals

Written via "0b" in the manner of other literals. e.g. 0b111001 = 57

src/Parser/Lexer/Source.idr

@@ -203,6 +203,20 @@ reservedSymbols
       ["%", "\\", ":", "=", "|", "|||", "<-", "->", "=>", "?", "!",
        "&", "**", "..", "~"]
 
+fromBinLit : String -> Integer
+fromBinLit str
+    = if length str <= 2
+         then 0
+         else let num = assert_total (strTail (strTail str)) in
+                fromBin . reverse . map castBin . unpack $ num
+    where
+      castBin : Char -> Integer
+      castBin '1' = 1; castBin _ = 0 -- This can only be '1' and '0' once lexed
+      fromBin : List Integer -> Integer
+      fromBin [] = 0
+      fromBin (0 :: xs) = 2 * fromBin xs
+      fromBin (1 :: xs) = 1 + (2 * fromBin xs)
+
 fromHexLit : String -> Integer
 fromHexLit str
   = if length str <= 2
@@ -230,6 +244,7 @@ rawTokens =
      (holeIdent, \x => HoleIdent (assert_total (strTail x)))] ++
     map (\x => (exact x, Symbol)) symbols ++
     [(doubleLit, \x => DoubleLit (cast x)),
+     (binLit, \x => IntegerLit (fromBinLit x)),
      (hexLit, \x => IntegerLit (fromHexLit x)),
      (octLit, \x => IntegerLit (fromOctLit x)),
      (digits, \x => IntegerLit (cast x)),

src/Text/Lexer.idr

@@ -166,6 +166,18 @@ export
 digits : Lexer
 digits = some digit
 
+||| Recognise a single binary digit
+||| /[0-1]/
+export
+binDigit : Lexer
+binDigit = pred (\c => c == '0' || c == '1')
+
+||| Recognise one or more binary digits
+||| /[0-1]+/
+export
+binDigits : Lexer
+binDigits = some binDigit
+
 ||| Recognise a single hexidecimal digit
 ||| /[0-9A-Fa-f]/
 export
@@ -332,6 +344,7 @@ charLit = let q = '\'' in
                       "DLE", "DC1", "DC2", "DC3", "DC4", "NAK", "SYN", "ETB",
                       "CAN", "EM",  "SUB", "ESC", "FS",  "GS",  "RS",  "US",
                       "SP",  "DEL"]
+                <|> (is 'b' <+> binDigits)
                 <|> (is 'x' <+> hexDigits)
                 <|> (is 'o' <+> octDigits)
                 <|> digits
@@ -342,6 +355,12 @@ export
 intLit : Lexer
 intLit = opt (is '-') <+> digits
 
+||| Recognise a binary literal, prefixed by "0b"
+||| /0b[0-1]+/
+export
+binLit : Lexer
+binLit = exact "0b" <+> binDigits
+
 ||| Recognise a hexidecimal literal, prefixed by "0x" or "0X"
 ||| /0[Xx][0-9A-Fa-f]+/
 export
@@ -349,7 +368,7 @@ hexLit : Lexer
 hexLit = approx "0x" <+> hexDigits
 
 ||| Recognise an octal literal, prefixed by "0o"
-||| /0[Xx][0-9A-Fa-f]+/
+||| /0o[0-9A-Fa-f]+/
 export
 octLit : Lexer
 octLit = exact "0o" <+> octDigits

tests/idris2/reg020/expected

@@ -1,5 +1,6 @@
 1/1: Building matchlits (matchlits.idr)
 Main> Main.test1 : Int -> Int
+test1 5 = 5
 test1 256 = 42
 test1 64 = 43
 test1 1234567890 = 44

tests/idris2/reg020/matchlits.idr

@@ -1,4 +1,5 @@
 test1 : Int -> Int
+test1 0b101 = 5
 test1 0x100 = 42
 test1 0o100 = 43
 test1 1234567890 = 44