1 files changed, 15 insertions, 4 deletions
diff --git a/Source/cmExprParser.y b/Source/cmExprParser.y
index ce467cf..c7c4a7b 100644
--- a/Source/cmExprParser.y
+++ b/Source/cmExprParser.y
@@ -118,19 +118,30 @@ shift:
   }
 
 term:
-  factor {
+  unary {
     $<Number>$ = $<Number>1;
   }
-| term exp_TIMES factor {
+| term exp_TIMES unary {
     $<Number>$ = $<Number>1 * $<Number>3;
   }
-| term exp_DIVIDE factor {
+| term exp_DIVIDE unary {
     $<Number>$ = $<Number>1 / $<Number>3;
   }
-| term exp_MOD factor {
+| term exp_MOD unary {
     $<Number>$ = $<Number>1 % $<Number>3;
   }
 
+unary:
+  factor {
+    $<Number>$ = $<Number>1;
+  }
+| exp_PLUS unary {
+    $<Number>$ = + $<Number>2;
+  }
+| exp_MINUS unary {
+    $<Number>$ = - $<Number>2;
+  }
+
 factor:
   exp_NUMBER {
     $<Number>$ = $<Number>1;