diff --git a/LexRain.x b/LexRain.x
index cc4a8d5..da870e3 100644
--- a/LexRain.x
+++ b/LexRain.x
@@ -54,12 +54,10 @@ $escapeChar = [cnrts \" \' \\ \n]
 @stringLiteral = \" ( @escape | [^\\\"] )* \"
 @charLiteral = \' ( @escape | [^\'] ) \'
 
--- Note that occam number literals don't include their signs -- if you say
--- "-3", then that's the operator "-" applied to the literal "3".
-@decimalLiteral = $decimalDigit+
+@decimalLiteral = ("-")? $decimalDigit+
 @hexLiteral = "#" $hexDigit+
 @exponent = ("+" | "-") $decimalDigit+
-@realLiteral = ( $decimalDigit+ "." $decimalDigit+ "E" @exponent )
+@realLiteral = ("-")? ( $decimalDigit+ "." $decimalDigit+ "E" @exponent )
              | ( $decimalDigit+ "." $decimalDigit+ )
 
 occam :-
diff --git a/RainParseTest.hs b/RainParseTest.hs
index 186cc29..a62d643 100644
--- a/RainParseTest.hs
+++ b/RainParseTest.hs
@@ -183,6 +183,9 @@ testLiteral =
   ,pass ("18446744073709551616", RP.literal, assertEqual "testLiteral 2" (intLiteral 18446744073709551616))  
   --2^100:  We should be able to parse this, but it will be rejected at a later stage:
   ,pass ("1267650600228229401496703205376", RP.literal, assertEqual "testLiteral 3" (intLiteral 1267650600228229401496703205376))  
+  --Test that both literal and expression parse -3 the same way:
+  ,pass ("-3", RP.literal, assertEqual "testLiteral 4" (intLiteral (-3)))
+  ,pass ("-3", RP.expression, assertEqual "testLiteral 5" (intLiteral (-3)))
   
   --Non-integers currently unsupported:
   ,fail ("0.",RP.literal)