include/AD/symbolic/expr.h

   1 //////////////////////////////////////////////////////////////////////////////
   2 // NOTICE:
   3 //
   4 // ADLib, Prop and their related set of tools and documentation are in the
   5 // public domain.   The author(s) of this software reserve no copyrights on
   6 // the source code and any code generated using the tools.  You are encouraged
   7 // to use ADLib and Prop to develop software, in both academic and commercial
   8 // settings, and are welcomed to incorporate any part of ADLib and Prop into
   9 // your programs.
  10 //
  11 // Although you are under no obligation to do so, we strongly recommend that
  12 // you give away all software developed using our tools.
  13 //
  14 // We also ask that credit be given to us when ADLib and/or Prop are used in
  15 // your programs, and that this notice be preserved intact in all the source
  16 // code.
  17 //
  18 // This software is still under development and we welcome(read crave for)
  19 // any suggestions and help from the users.
  20 //
  21 // Allen Leung (leunga@valis.cs.nyu.edu)
  22 // 1994-1995
  23 //////////////////////////////////////////////////////////////////////////////
  24 #ifndef symbolic_expressions_base_class_h
  25 #define symbolic_expressions_base_class_h
  26
  27 #include <AD/generic/generic.h>
  28 #include <AD/gc/gcobject.h>
  29 #include <AD/persist/pobject.h>
  30
  31 //////////////////////////////////////////////////////////////////////////////
  32 //
  33 //  Forward declarations
  34 //
  35 //////////////////////////////////////////////////////////////////////////////
  36 class SymbolicUnifier;
  37 class SymbolicExprPrinter;
  38 class SymbolicExprReader;
  39 class SymbolicEnvironment;
  40
  41 //////////////////////////////////////////////////////////////////////////////
  42 //
  43 //  SymbolicExpr is a base class for all symbolic expressions.
  44 //
  45 //////////////////////////////////////////////////////////////////////////////
  46 class SymbolicExpr : public GCObject, public PObject
  47 {
  48 public:
  49    ///////////////////////////////////////////////////////////////////////////
  50    //
  51    //  Constructor, destructor and copying
  52    //
  53    ///////////////////////////////////////////////////////////////////////////
  54             SymbolicExpr();
  55    virtual ~SymbolicExpr();
  56    virtual SymbolicExpr * copy () const;
  57
  58    ///////////////////////////////////////////////////////////////////////////
  59    //
  60    //  Interfaces to a symbolic expression.
  61    //
  62    ///////////////////////////////////////////////////////////////////////////
  63    virtual Bool                 unify (SymbolicExpr *, SymbolicUnifier&) = 0;
  64    virtual SymbolicExpr *       eval  (SymbolicEnvironment&) const;
  65    virtual SymbolicExprPrinter& print (SymbolicExprPrinter&) const = 0;
  66    virtual SymbolicExprReader&  read  (SymbolicExprReader&) = 0;
  67 };
  68
  69 #endif