special casing the optional ident, which is conflicting with pi and e as numbers

Author: ylafon

org/w3c/css/parser/analyzer/CssParser.jj

@@ -3338,8 +3338,8 @@ CssCheckableValue mathfunctionround() :
 }
 {
     ( n=<FUNCTIONROUND> { c = new CssMathFunction(ac, n.image); }
-        ( <S> )* ( LOOKAHEAD(2) v=mathsum() { c.addValue(v); }
-     | n=<IDENT> { c.addValue(CssIdent.getIdent(convertIdent(n.image))); } )
+        ( <S> )* (  LOOKAHEAD(2) n=<IDENT> { c.addValue(CssIdent.getIdent(convertIdent(n.image))); } 
+     | v=mathsum() { c.addValue(v); } )
         ( <S> )* ( <COMMA> ( <S> )* v=mathsum() {
                 c.addValue(v);
         } ( <S> )* )* <RPAREN> ) {

org/w3c/css/values/CssMathFunction.java

@@ -278,6 +278,15 @@ private void _computeResultingTypeRound(boolean is_final)
         }
         if (vsize == 2) {
             valtype1 = values.get(0).getType();
+            // parsing artefact
+            if (valtype1 == CssTypes.CSS_IDENT) {
+                try {
+                    CssNumber n = new CssNumber();
+                    n.set(values.get(0).getIdent().toString(), ac);
+                    valtype1 = CssTypes.CSS_NUMBER;
+                } catch (Exception ignored) {
+                }
+            }
             valtype2 = values.get(1).getType();
         } else {  // 3 values
             CssValue v = values.get(0);