Treat Infinity and NaN as reserved words

src/grammar.coffee

@@ -145,7 +145,6 @@ grammar =
   # they can also serve as keys in object literals.
   AlphaNumeric: [
     o 'NUMBER',                                 -> new NumberLiteral $1
-    o 'INFINITY',                               -> new InfinityLiteral $1
     o 'String'
   ]
 
@@ -168,6 +167,8 @@ grammar =
     o 'UNDEFINED',                              -> new UndefinedLiteral
     o 'NULL',                                   -> new NullLiteral
     o 'BOOL',                                   -> new BooleanLiteral $1
+    o 'INFINITY',                               -> new InfinityLiteral $1
+    o 'NAN',                                    -> new NaNLiteral
   ]
 
   # Assignment of a variable, property, or index to a value.

src/lexer.coffee

@@ -777,7 +777,10 @@ JS_KEYWORDS = [
 ]
 
 # CoffeeScript-only keywords.
-COFFEE_KEYWORDS = ['undefined', 'then', 'unless', 'until', 'loop', 'of', 'by', 'when']
+COFFEE_KEYWORDS = [
+  'undefined', 'Infinity', 'NaN'
+  'then', 'unless', 'until', 'loop', 'of', 'by', 'when'
+]
 
 COFFEE_ALIAS_MAP =
   and  : '&&'
@@ -939,7 +942,7 @@ BOOL = ['TRUE', 'FALSE']
 # of a function invocation or indexing operation.
 CALLABLE  = ['IDENTIFIER', 'PROPERTY', ')', ']', '?', '@', 'THIS', 'SUPER']
 INDEXABLE = CALLABLE.concat [
-  'NUMBER', 'INFINITY', 'STRING', 'STRING_END', 'REGEX', 'REGEX_END'
+  'NUMBER', 'INFINITY', 'NAN', 'STRING', 'STRING_END', 'REGEX', 'REGEX_END'
   'BOOL', 'NULL', 'UNDEFINED', '}', '::'
 ]
 

src/nodes.coffee

@@ -404,6 +404,14 @@ exports.InfinityLiteral = class InfinityLiteral extends NumberLiteral
   compileNode: ->
     [@makeCode '2e308']
 
+exports.NaNLiteral = class NaNLiteral extends NumberLiteral
+  constructor: ->
+    super 'NaN'
+
+  compileNode: (o) ->
+    code = [@makeCode '0/0']
+    if o.level >= LEVEL_OP then @wrapInBraces code else code
+
 exports.StringLiteral = class StringLiteral extends Literal
 
 exports.RegexLiteral = class RegexLiteral extends Literal

src/rewriter.coffee

@@ -483,9 +483,11 @@ IMPLICIT_FUNC    = ['IDENTIFIER', 'PROPERTY', 'SUPER', ')', 'CALL_END', ']', 'IN
 
 # If preceded by an `IMPLICIT_FUNC`, indicates a function invocation.
 IMPLICIT_CALL    = [
-  'IDENTIFIER', 'PROPERTY', 'NUMBER', 'INFINITY', 'STRING', 'STRING_START', 'JS', 'REGEX', 'REGEX_START'
-  'NEW', 'PARAM_START', 'CLASS', 'IF', 'TRY', 'SWITCH', 'THIS', 'BOOL', 'NULL'
-  'UNDEFINED', 'UNARY', 'YIELD', 'UNARY_MATH', 'SUPER', 'THROW'
+  'IDENTIFIER', 'PROPERTY', 'NUMBER', 'INFINITY', 'NAN'
+  'STRING', 'STRING_START', 'REGEX', 'REGEX_START', 'JS'
+  'NEW', 'PARAM_START', 'CLASS', 'IF', 'TRY', 'SWITCH', 'THIS'
+  'UNDEFINED', 'NULL', 'BOOL'
+  'UNARY', 'YIELD', 'UNARY_MATH', 'SUPER', 'THROW'
   '@', '->', '=>', '[', '(', '{', '--', '++'
 ]
 

test/numbers.coffee

@@ -83,3 +83,6 @@ test "Infinity", ->
   eq Infinity, CoffeeScript.eval "0x#{Array(256 + 1).join('f')}"
   eq Infinity, CoffeeScript.eval Array(500 + 1).join('9')
   eq Infinity, 2e308
+
+test "NaN", ->
+  ok isNaN 1/NaN

test/operators.coffee

@@ -259,7 +259,7 @@ test "chained operations should evaluate each value only once", ->
 
 test "#891: incorrect inversion of chained comparisons", ->
   ok (true unless 0 > 1 > 2)
-  ok (true unless (NaN = 0/0) < 0/0 < NaN)
+  ok (true unless (this.NaN = 0/0) < 0/0 < this.NaN)
 
 test "#1234: Applying a splat to :: applies the splat to the wrong object", ->
   nonce = {}