41 lines
897 B
TypeScript
41 lines
897 B
TypeScript
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import { Pos, Token } from "./Token.ts";
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class Lexer {
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private index = 0;
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private line = 1;
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private col = 1;
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public constructor (private text: string) {}
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public next(): Token | null { return null }
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private done(): boolean { return this.index >= this.text.length; }
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private current(): string { return this.text[this.index]; }
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private step() {
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if (this.done())
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return;
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if (this.current() === "\n") {
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this.line += 1;
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this.col = 1;
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} else {
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this.col += 1;
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}
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this.index += 1;
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}
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private pos(): Pos {
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return {
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index: this.index,
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line: this.line,
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col: this.col
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}
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}
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private token(type: string, pos: Pos): Token {
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const length = this.index - pos.index;
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return { type, pos, length };
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}
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}
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