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/*****************************************************************************
*
* Copyright (c) 2000 - 2017, Lawrence Livermore National Security, LLC
* Produced at the Lawrence Livermore National Laboratory
* LLNL-CODE-442911
* All rights reserved.
*
* This file is part of VisIt. For details, see https://visit.llnl.gov/. The
* full copyright notice is contained in the file COPYRIGHT located at the root
* of the VisIt distribution or at http://www.llnl.gov/visit/copyright.html.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the disclaimer below.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the disclaimer (as noted below) in the
* documentation and/or other materials provided with the distribution.
* - Neither the name of the LLNS/LLNL nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL LAWRENCE LIVERMORE NATIONAL SECURITY,
* LLC, THE U.S. DEPARTMENT OF ENERGY OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
*****************************************************************************/
#include "Symbol.h"
#include "Dictionary.h"
#include "Rule.h"
#include "Token.h"
using std::vector;
using std::string;
using std::map;
// ****************************************************************************
// Constructor: Symbol::Symbol
//
// Purpose:
// Creates a terminal from the token type.
//
// Programmer: Jeremy Meredith
// Creation: April 5, 2002
//
// Modifications:
// Jeremy Meredith, Wed Jun 8 17:08:35 PDT 2005
// All symbols are now added to a dictionary instead of static members.
//
// ****************************************************************************
Symbol::Symbol(Dictionary &dict, int tt)
: type(Terminal), terminaltype(tt), displaystring(GetTokenTypeString(tt))
{
index = dict.AddTerminal(this);
}
// ****************************************************************************
// Constructor: Symbol::Symbol
//
// Purpose:
// Creates a terminal from the token type, overriding the display
// string with a known one.
//
// Programmer: Jeremy Meredith
// Creation: November 24, 2004
//
// Modifications:
// Jeremy Meredith, Wed Jun 8 17:08:35 PDT 2005
// All symbols are now added to a dictionary instead of static members.
//
// ****************************************************************************
Symbol::Symbol(Dictionary &dict, int tt, const string &s)
: type(Terminal), terminaltype(tt), displaystring(s)
{
index = dict.AddTerminal(this);
}
// ****************************************************************************
// Constructor: Symbol::Symbol
//
// Purpose:
// Creates a nonterminal from its name.
//
// Programmer: Jeremy Meredith
// Creation: April 5, 2002
//
// Modifications:
// Jeremy Meredith, Wed Jun 8 17:08:35 PDT 2005
// All symbols are now added to a dictionary instead of static members.
//
// ****************************************************************************
Symbol::Symbol(Dictionary &dict, const string &s)
: type(NonTerminal), terminaltype(0), displaystring(s)
{
index = dict.AddNonTerminal(this);
}
// ****************************************************************************
// Method: Symbol::operator==
//
// Purpose:
// Tests for equality. The displaystrings should always be unique.
//
// Programmer: Jeremy Meredith
// Creation: April 5, 2002
//
// ****************************************************************************
bool
Symbol::operator==(const Symbol &rhs) const
{
return displaystring == rhs.displaystring;
}
// ****************************************************************************
// Method: operator<<(ostream, Symbol)
//
// Purpose:
// Prints the symbol.
//
// Programmer: Jeremy Meredith
// Creation: April 5, 2002
//
// ****************************************************************************
ostream &operator<<(ostream &o, const Symbol &s)
{
o << s.displaystring.c_str();
return o;
}
// ****************************************************************************
// Method: Symbol::IsNullable
//
// Purpose:
// Checks if a symbol can produce, even indirectly, the null string.
//
// Programmer: Jeremy Meredith
// Creation: April 5, 2002
//
// ****************************************************************************
bool
Symbol::IsNullable(const vector<const Rule*> &rules) const
{
if (type == Terminal)
return false;
for (size_t i=0; i<rules.size(); i++)
{
if (rules[i]->GetLHS() == this)
{
if (rules[i]->IsNullable(rules))
return true;
}
}
return false;
}
// ****************************************************************************
// Method: Symbol::GetFirstSet
//
// Purpose:
// Gets the first set for any production of this symbol.
// For terminals, the first set is the identity operation.
//
// Programmer: Jeremy Meredith
// Creation: April 5, 2002
//
// ****************************************************************************
SymbolSet
Symbol::GetFirstSet(const vector<const Rule*> &rules) const
{
SymbolSet first;
if (type == Terminal)
{
first.insert(this);
}
else
{
for (size_t i=0; i<rules.size(); i++)
{
if (rules[i]->GetLHS() == this &&
// Try to avoid infinite recursion -- this should be improved!
(rules[i]->GetRHS().Empty() || rules[i]->GetRHS()[0] != this))
{
first.merge( rules[i]->GetRHS().GetFirstSet(rules) );
}
}
}
return first;
}
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