Adding debug options to vhdl parser generator

JavaCC contains by default options to get more information about the parser paths used (analogous to the -d option of flex).
- Makefile
  - adding option (JAVACC_FLAGS) for easier use of JavaCC options
  - adding possibility to reset generated files to their git versions.
- vhdlstring.h adding functions required by debug options (debug_token_manager)

vhdlparser/Makefile

@@ -7,16 +7,48 @@
 # for any purpose. It is provided "as is" without express or implied warranty.
 # See the GNU General Public License for more details.
 #
-# Documents produced by Doxygen are derivative works derived from the
+# Documents produced by doxygen are derivative works derived from the
 # input used in their production; they are not affected by this license.
 #
 
-regenerate:
-	rm -f CharStream.cc CharStream.h ErrorHandler.h ParseException.cc ParseException.h \
+#
+# Files generated by javacc 
+#
+GEN_FILES=CharStream.cc CharStream.h ErrorHandler.h ParseException.cc ParseException.h \
 	      Token.cc Token.h TokenManager.h TokenMgrError.cc TokenMgrError.h VhdlParser.cc VhdlParser.h \
 	      VhdlParserConstants.h VhdlParserTokenManager.cc VhdlParserTokenManager.h \
               JavaCC.h
-	javacc vhdlparser.jj
-	cp JavaCC.h.in JavaCC.h
+#
+# Generate parser (default target)
+#
+# when generating the parser with debug options it will look like:
+#   make JAVACC_FLAGS=-debug_parser 
+#  or
+#   make JAVACC_FLAGS="-debug_parser -debug_lookahead"
+#
+# Available debug options:
+#  -debug_parser
+#  -debug_token_manager
+#  -debug_lookahead
+#
+# For other javacc settings / options consult the documentation of javacc.
+
+regenerate:
+	@rm -f $(GEN_FILES)
+	@javacc $(JAVACC_FLAGS) vhdlparser.jj
+	@cp JavaCC.h.in JavaCC.h
+
+#
+# reset the generated files back to their versions from git.
+#
+
+reset_gen_files:
+	@rm -f $(GEN_FILES)
+	@git checkout $(GEN_FILES)
+
+help:
+	@echo "Targets:"
+	@echo "  regenerate (default)"
+	@echo "  reset_gen_files"
 
 FORCE:

vhdlparser/vhdlstring.h

@@ -9,6 +9,7 @@
 /** @brief Minimal string class with std::string like behaviour that fulfills the JavaCC
  *  string requirements.
  */
+
 class VhdlString
 {
   public:
@@ -93,11 +94,18 @@ class VhdlString
     void        clear()                 { free(m_str); init(); }
     VhdlString  &operator+=(char c)      { char s[2]; s[0]=c; s[1]=0; return append(s); }
     VhdlString  &operator+=(const char *s) { return append(s); }
+    VhdlString  &operator+=(VhdlString s) { return append(s); }
+    VhdlString   operator+ (const char *s) { return append(s); }
 
   private:
     void init() { m_str=(char*)calloc(1,1); m_len=0; }
     char *m_str;
     int   m_len;
 };
 
+// declare it static otherwise we will get:
+//   multiple definition of `operator+(char const*, VhdlString)'
+// as we are in an include file
+static VhdlString   operator+ (const char *s, VhdlString v) { return VhdlString(s).append(v); }
+
 #endif