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53 lines
1.2 KiB
53 lines
1.2 KiB
2 years ago
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import { SyntaxError } from './SyntaxError.js';
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const TAB = 9;
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const N = 10;
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const F = 12;
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const R = 13;
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const SPACE = 32;
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export class Tokenizer {
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constructor(str) {
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this.str = str;
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this.pos = 0;
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}
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charCodeAt(pos) {
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return pos < this.str.length ? this.str.charCodeAt(pos) : 0;
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}
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charCode() {
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return this.charCodeAt(this.pos);
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}
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nextCharCode() {
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return this.charCodeAt(this.pos + 1);
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}
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nextNonWsCode(pos) {
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return this.charCodeAt(this.findWsEnd(pos));
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}
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findWsEnd(pos) {
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for (; pos < this.str.length; pos++) {
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const code = this.str.charCodeAt(pos);
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if (code !== R && code !== N && code !== F && code !== SPACE && code !== TAB) {
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break;
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}
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}
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return pos;
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}
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substringToPos(end) {
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return this.str.substring(this.pos, this.pos = end);
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}
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eat(code) {
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if (this.charCode() !== code) {
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this.error('Expect `' + String.fromCharCode(code) + '`');
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}
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this.pos++;
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}
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peek() {
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return this.pos < this.str.length ? this.str.charAt(this.pos++) : '';
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}
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error(message) {
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throw new SyntaxError(message, this.str, this.pos);
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}
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};
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