Add error on misused define.

src/V3PreLex.l

@@ -244,6 +244,11 @@ bom             [\357\273\277]
                           // Note paren level 0 means before "(" of starting args
                           // Level 1 means "," between arguments
                           // Level 2+ means one inside the () of an argument
+                          if (LEXP->m_parenLevel == 1) {  // Starting (
+                              if (!VString::isWhitespace(LEXP->m_defValue)) {
+                                  yyerrorf("Illegal text before '(' that starts define arguments");
+                              }
+                          }
                           if (LEXP->m_parenLevel>1) {
                               appendDefValue(yytext, yyleng); FL_BRK;
                           } else {

src/V3String.cpp

@@ -114,6 +114,13 @@ string VString::spaceUnprintable(const string& str) {
     return out;
 }
 
+bool VString::isWhitespace(const string& str) {
+    for (string::const_iterator pos = str.begin(); pos != str.end(); ++pos) {
+        if (!isspace(*pos)) return false;
+    }
+    return true;
+}
+
 //######################################################################
 // VHashSha256
 

src/V3String.h

@@ -74,6 +74,8 @@ public:
     // Replace any unprintable with space
     // This includes removing tabs, so column tracking is correct
     static string spaceUnprintable(const string& str);
+    // Return true if only whitespace or ""
+    static bool isWhitespace(const string& str);
 };
 
 //######################################################################