52 lines
1.4 KiB
JavaScript
52 lines
1.4 KiB
JavaScript
/**
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* LogarithmPlotter - Create graphs with logarithm scales.
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* Copyright (C) 2022 Ad5001
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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.pragma library
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class InputExpression {
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constructor(expression) {
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this.position = 0;
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this.input = expression;
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}
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next() {
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return this.input[this.position++];
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}
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peek() {
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return this.input[this.position];
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}
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skip(char) {
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if(!atEnd() && peek() == char) {
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this.position++;
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} else {
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this.raise("Unexpected character " + peek() + ". Expected character " + char);
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}
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}
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atEnd() {
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return this.position >= this.input.length;
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}
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raise(message) {
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throw new SyntaxError(message + " at " + this.position ".")
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}
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}
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