From cbedc425b810dd887da2a52d2f33df2bced0f831 Mon Sep 17 00:00:00 2001
From: "Juan J. Martinez" <jjm@usebox.net>
Date: Sun, 21 Aug 2022 14:28:30 +0100
Subject: Support for binary numbers witg 0b[0-1] notation

---
 src/Lexer.hs | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

(limited to 'src')

diff --git a/src/Lexer.hs b/src/Lexer.hs
index 4938cfe..848a892 100644
--- a/src/Lexer.hs
+++ b/src/Lexer.hs
@@ -1,5 +1,6 @@
 module Lexer where
 
+import Data.Char (digitToInt)
 import Text.Parsec
 import Text.Parsec.Language (emptyDef)
 import Text.Parsec.String (Parser)
@@ -17,8 +18,16 @@ scanner = T.makeTokenParser style
           T.reservedNames = names
         }
 
+binNum :: Parser Integer
+binNum = do
+  _ <- char '0'
+  _ <- oneOf "bB"
+  digits <- many1 $ oneOf "01"
+  let n = foldl (\x d -> 2 * x + toInteger (digitToInt d)) 0 digits
+  seq n $ return n
+
 integer :: Parser Integer
-integer = T.integer scanner
+integer = binNum <|> T.integer scanner
 
 parens :: Parser a -> Parser a
 parens = T.parens scanner
-- 
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