include/AD/automata/gla.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
  22 // 1994
  23 //////////////////////////////////////////////////////////////////////////////
  24
  25 #ifndef general_lookahead_automata_h
  26 #define general_lookahead_automata_h
  27
  28 #include <AD/automata/grammar.h>     // grammars
  29 #include <AD/memory/mem.h>           // memory manager
  30 #include <AD/contain/bitset.h>       // bit sets
  31
  32 //////////////////////////////////////////////////////////////////////////////
  33 //  Class GLA represents a ``general_lookahead_automaton'' (see Terrance
  34 //  Parr's PhD thesis at Purdue U.)
  35 //////////////////////////////////////////////////////////////////////////////
  36 class GLA : public DFATables {
  37
  38    GLA(const GLA&);               // no copy constructor
  39    void operator = (const GLA&);  // no assignment
  40
  41 public:
  42
  43    ///////////////////////////////////////////////////////////////////////////
  44    //  Import some types from superclass.
  45    ///////////////////////////////////////////////////////////////////////////
  46    typedef DFATables            Super;
  47    typedef Super::State         State;
  48    typedef Super::Rule          Rule;
  49    typedef Super::Symbol        Symbol;
  50    typedef Grammar::NonTerminal NonTerminal;
  51    typedef Grammar::Terminal    Terminal;
  52    typedef Grammar::EquivMap    EquivMap;
  53    typedef BitSet               NonTerminalSet;
  54
  55    ///////////////////////////////////////////////////////////////////////////
  56    //  Define the GLA internals:
  57    //     A GLA node is represented by the following class.
  58    //     It is basically a labeled graph represented in child-sibling
  59    //     format.
  60    ///////////////////////////////////////////////////////////////////////////
  61    class Node {
  62
  63       Node(const Node&);               // no copy constructor
  64       void operator = (const Node&);   // no assignment
  65
  66    public:
  67
  68       Node();
  69      ~Node();
  70    };
  71
  72 protected:
  73
  74    ///////////////////////////////////////////////////////////////////////////
  75    //  The internals of this class is hidden.
  76    ///////////////////////////////////////////////////////////////////////////
  77    Mem&             mem;      // internal memory manager
  78    class GLA_Impl * intern;   // internal rep.
  79    virtual void clean_up();   // method to clean up internal rep.
  80
  81 public:
  82
  83    ///////////////////////////////////////////////////////////////////////////
  84    //  Constructors and destructor
  85    ///////////////////////////////////////////////////////////////////////////
  86             GLA( Mem& );
  87             GLA( const Grammar&, Mem& );
  88    virtual ~GLA();
  89
  90    ///////////////////////////////////////////////////////////////////////////
  91    //  Method to construct the LR(0) automaton and compute the GLA
  92    //  from the grammar.
  93    ///////////////////////////////////////////////////////////////////////////
  94    virtual void build(const Grammar&);
  95
  96    ///////////////////////////////////////////////////////////////////////////
  97    //  Operations on a GLA:
  98    //     `look()' -- compute the linear lookahead approximation from a
  99    //                 node of the GLA, where 'k' is the lookahead count.
 100    ///////////////////////////////////////////////////////////////////////////
 101    const NonTerminalSet& look (const Node *, int k);
 102
 103    ///////////////////////////////////////////////////////////////////////////
 104    //  Method to print a report.
 105    ///////////////////////////////////////////////////////////////////////////
 106    virtual ostream& print_report(ostream&, Bool, Bool);
 107 };
 108
 109 #endif