lib-src/rewrite/twig.cc

   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 //////////////////////////////////////////////////////////////////////////////
  26 //  This file contains the implementation of a top-down tree parser
  27 //  with dynamic programming.  See Aho, Tsiang, et al. for details.
  28 //////////////////////////////////////////////////////////////////////////////
  29
  30 #include <iostream>
  31 #include <AD/rewrite/twig.h>     // twig module
  32 #include <AD/memory/boundtag.h>  // boundary tag memory maager
  33 #include <AD/contain/bitset.h>   // bit sets
  34
  35 //////////////////////////////////////////////////////////////////////////////
  36 //  Make hidden types visible
  37 //////////////////////////////////////////////////////////////////////////////
  38 typedef Twig::Symbol Symbol;
  39 typedef Twig::State  State;
  40 typedef Twig::Offset Offset;
  41 typedef Twig::Rule   Rule;
  42
  43 //////////////////////////////////////////////////////////////////////////////
  44 //  Internal representation of the tree matcher
  45 //////////////////////////////////////////////////////////////////////////////
  46 class Twig_Impl {
  47 public:
  48    Twig_Impl() {}
  49   ~Twig_Impl() {}
  50 };
  51
  52 //////////////////////////////////////////////////////////////////////////////
  53 //  Constructor and destructor for class Twig.
  54 //////////////////////////////////////////////////////////////////////////////
  55 Twig:: Twig( const Offset base_table  [],
  56              const State  check_table [],
  57              const State  failure     [],
  58              const State  next_table  [],
  59              const Rule   rule_table  []
  60            ) :
  61    Super(base_table,check_table,failure,next_table,rule_table),
  62    mem(* new BoundaryTag) {}
  63 Twig::~Twig() { close(); delete (&mem); }
  64
  65 //////////////////////////////////////////////////////////////////////////////
  66 //  Method to initialize the tree reducer.
  67 //////////////////////////////////////////////////////////////////////////////
  68 void Twig::open()
  69 {  if (impl) delete impl;
  70    impl = new Twig_Impl();
  71 }
  72
  73 //////////////////////////////////////////////////////////////////////////////
  74 //  Method to clean up the tree reducer.
  75 //////////////////////////////////////////////////////////////////////////////
  76 void Twig::close()
  77 {  if (impl) delete impl; impl = 0; }
  78
  79 //////////////////////////////////////////////////////////////////////////////
  80 //  Method to perform the actual reduction.
  81 //////////////////////////////////////////////////////////////////////////////
  82 void Twig::reduce()
  83 {
  84 }