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deb-goldedplus/goldlib/gall/gevalhum.cpp

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2000-02-25 10:15:17 +00:00
// This may look like C code, but it is really -*- C++ -*-
// ------------------------------------------------------------------
// The Goldware Library
// Copyright (C) 1990-1999 Odinn Sorensen
// ------------------------------------------------------------------
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public
// License along with this program; if not, write to the Free
// Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
// MA 02111-1307, USA
// ------------------------------------------------------------------
// $Id$
// ------------------------------------------------------------------
// Human (left-to-right) expression evaluator class.
// ------------------------------------------------------------------
#include <gdefs.h>
#include <geval.h>
// ------------------------------------------------------------------
gevalhum::gevalhum() {
}
// ------------------------------------------------------------------
gevalhum::~gevalhum() {
}
// ------------------------------------------------------------------
int gevalhum::evaluate() {
while(vstk.size() and ostk.size()) {
while(ostk.size()) {
int* vptr = vstk.begin();
ops* optr = ostk.begin();
while(optr < ostk.end()) {
if(optr < (ostk.end() - 1)) {
if(*optr == parenthesis_left) {
if(optr[1] == parenthesis_right) {
ostk.erase(optr, optr+2);
break;
}
else {
optr++;
}
continue;
}
else if(((*optr == negation) or (*optr == logic_not)) and (optr[1] == parenthesis_left)) {
optr++;
continue;
}
else if((*optr < optr[1]) and (optr[1] != parenthesis_right)) {
optr++;
vptr++;
continue;
}
}
if(ostk.size()) {
if((*optr == negation) or (*optr == logic_not))
*vptr = evaluate_ops(optr, vptr, vptr);
else {
*vptr = evaluate_ops(optr, vptr, vptr+1);
if(vptr+1 < vstk.end())
vstk.erase(vptr+1);
}
ostk.erase(optr);
}
break;
}
}
}
return pop_value();
}
// ------------------------------------------------------------------