Binary notation integers (0b100 as 4).

lib/coffee-script/lexer.js

@@ -107,11 +107,14 @@
     };
 
     Lexer.prototype.numberToken = function() {
-      var match, number;
+      var is_binary, match, number, numlen;
       if (!(match = NUMBER.exec(this.chunk))) return 0;
       number = match[0];
+      numlen = number.length;
+      is_binary = /0b([01]+)/.exec(number);
+      if (is_binary) number = (parseInt(is_binary[1], 2)).toString();
       this.token('NUMBER', number);
-      return number.length;
+      return numlen;
     };
 
     Lexer.prototype.stringToken = function() {
@@ -620,7 +623,7 @@
 
   IDENTIFIER = /^([$A-Za-z_\x7f-\uffff][$\w\x7f-\uffff]*)([^\n\S]*:(?!:))?/;
 
-  NUMBER = /^0x[\da-f]+|^\d*\.?\d+(?:e[+-]?\d+)?/i;
+  NUMBER = /^0x[\da-f]+|^0b[01]+|^\d*\.?\d+(?:e[+-]?\d+)?/i;
 
   HEREDOC = /^("""|''')([\s\S]*?)(?:\n[^\n\S]*)?\1/;
 

src/lexer.coffee

@@ -133,8 +133,14 @@ exports.Lexer = class Lexer
   numberToken: ->
     return 0 unless match = NUMBER.exec @chunk
     number = match[0]
+    numlen = number.length
+    # Now, since it is not JavaScript-descended, if it is binary, we will have
+    # to massage it into something similar and then hand it over. May the user
+    # forgive us.
+    is_binary = /0b([01]+)/.exec number
+    number = (parseInt is_binary[1], 2).toString() if is_binary
     @token 'NUMBER', number
-    number.length
+    numlen
 
   # Matches strings, including multi-line strings. Ensures that quotation marks
   # are balanced within the string's contents, and within nested interpolations.
@@ -578,6 +584,7 @@ IDENTIFIER = /// ^
 
 NUMBER     = ///
   ^ 0x[\da-f]+ |                              # hex
+  ^ 0b[01]+ |                              # binary
   ^ \d*\.?\d+ (?:e[+-]?\d+)?  # decimal
 ///i
 

test/numbers.coffee

@@ -7,8 +7,17 @@
 # * Scientific Notation Integer Literals
 # * Scientific Notation Non-Integer Literals
 # * Non-Integer Literals
+# * Binary Integer Literals
 
 
+# Binary Integer Literals
+# Binary notation is understood as would be decimal notation.
+
+test "Parser recognises binary numbers", ->
+  eq 4, 0b100.valueOf()
+  eq '11', 0b100.toString 3
+  eq '100', 0b100['toString'] 2
+
 # Decimal Integer Literals
 
 test "call methods directly on numbers", ->