botlang /
botlang-js
| Lines of Code | 81 |
| Duplicated Lines | 0 |
| Ratio | 0 % |
| Changes | 2 | ||
| Bugs | 0 | Features | 0 |
| 1 | 'use strict'; |
||
| 2 | |||
| 3 | /** |
||
| 4 | * Representation of the input stream with some util functions. The class is used by the botlang |
||
| 5 | * lexer which takes an instance of `Input` as a constructor argument and converts it into a |
||
| 6 | * token stream. |
||
| 7 | */ |
||
| 8 | class Input { |
||
| 9 | /** |
||
| 10 | * Create an Input. |
||
| 11 | * @param {String} input |
||
| 12 | */ |
||
| 13 | constructor(input) { |
||
| 14 | /** |
||
| 15 | * @private |
||
| 16 | * @type {Number} |
||
| 17 | */ |
||
| 18 | this.column = 0; |
||
| 19 | /** |
||
| 20 | * @private |
||
| 21 | * @type {String} |
||
| 22 | */ |
||
| 23 | this.input = `${input}`; |
||
| 24 | /** |
||
| 25 | * @private |
||
| 26 | * @type {Number} |
||
| 27 | */ |
||
| 28 | this.line = 1; |
||
| 29 | /** |
||
| 30 | * @private |
||
| 31 | * @type {Number} |
||
| 32 | */ |
||
| 33 | this.position = 0; |
||
| 34 | } |
||
| 35 | |||
| 36 | /** |
||
| 37 | * Determine whether or not there are no more values in the stream. |
||
| 38 | * @return {Boolean} |
||
| 39 | */ |
||
| 40 | eof() { |
||
| 41 | return '' === this.peek(); |
||
| 42 | } |
||
| 43 | |||
| 44 | /** |
||
| 45 | * Throw a new Error. |
||
| 46 | * @param {String} message |
||
| 47 | * @throws {Error} |
||
| 48 | * @return {void} |
||
| 49 | */ |
||
| 50 | error(message) { |
||
| 51 | throw new Error(`${message} (Line: ${this.line}, Column: ${this.column})`); |
||
| 52 | } |
||
| 53 | |||
| 54 | /** |
||
| 55 | * Return the next character from the input stream. |
||
| 56 | * @return {String} |
||
| 57 | */ |
||
| 58 | next() { |
||
| 59 | const character = this.input.charAt(this.position += 1); |
||
| 60 | |||
| 61 | // Keep track of the current column and line number |
||
| 62 | if ('\n' === character) { |
||
| 63 | this.column = 0; |
||
| 64 | this.line += 1; |
||
| 65 | } else { |
||
| 66 | this.column += 1; |
||
| 67 | } |
||
| 68 | |||
| 69 | return character; |
||
| 70 | } |
||
| 71 | |||
| 72 | /** |
||
| 73 | * Return the character from the current position without "consuming" it. |
||
| 74 | * @return {String} |
||
| 75 | */ |
||
| 76 | peek() { |
||
| 77 | return this.input.charAt(this.position); |
||
| 78 | } |
||
| 79 | } |
||
| 80 | |||
| 81 | export default Input; |
||
| 82 |
