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