Big chunk of changes:

* Fixed bugs in option parsing
* Simplified the main.cpp significantly (more c++ like)
* Added the null kind, expr value, and expression, with the default constructor public
* Simplified commands, we need to discuss this in the meeting (what to do with command results?)
* Removed all the lex/yacc files
* Symbol table is now a templated class, as we will have tables for variables, predicates and functions
* The ANTLR parsing infrastructure/makefiles is all in. SMT lib Boolean benchmarks should parse + giving nice error such as 
      Parse Error: /home/dejan/eclipse-cxx/smtlib-parser/test/test4.smt:3:16: Undeclared variable p
      Parse Error: /home/dejan/eclipse-cxx/smtlib-parser/test/test2.smt:2:11: unexpected token: sa
      
Didn't add any unit tests as the unit testing doesn't work with the updated build system -- it doesn't know how to create directories in the corresponding build directory.

TODO: 
 * add the PL grammar and unit test when the testing becomes available
 * with this build setup my eclipse debugger doesn't work.  Might have something to do with the visibility of symbols?
 * i'm getting g++ depracated warnings regarding the hash_map from the symbol table, need to figure out how to use it in a standard manner. the new <unordered_map> header is for C++0x, and the <ext/hash_map> is getting deprecation warningns... weird.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/expr/expr.h b/src/expr/expr.h
index 5a11e0fbd..0fcb5ea6a 100644
--- a/src/expr/expr.h
+++ b/src/expr/expr.h
@@ -60,6 +60,10 @@ class CVC4_PUBLIC Expr {
   friend class ExprManager;
 
 public:
+
+  /** Default constructor, makes a null expression. */
+  CVC4_PUBLIC Expr();
+
   CVC4_PUBLIC Expr(const Expr&);
 
   /** Destructor.  Decrements the reference count and, if zero,
@@ -103,6 +107,9 @@ public:
   inline iterator end() const;
 
   void toString(std::ostream&) const;
+
+  bool isNull() const;
+
 };/* class Expr */
 
 }/* CVC4 namespace */