combine-parser-org-mode.ts

import * as fs from 'fs';
import { parse } from 'querystring';

const data = fs.readFileSync('./research.org', 'utf-8');

interface Token {
    success: boolean;
    value?: string;
    rest?: string;
    data?: string;
    error?: Error;
};

interface ParserFn {
    (input?: string): Token;
};

const match_char = (c: string): ParserFn => (input: string): Token => {
    if (input[0] === c) {
        return <Token>{
            success: true,
            value: input[0],
            rest: input.slice(1),
            data: null,
            error: null
        };
    }
    throw new Error(`MatchCharError: Expected ${c}, found ${input[0]}`);
};

const match_any_char_to_eol = (): ParserFn => (input: string): Token => {
    let parsed: string = "";
    while (input[0] != "\n" && input.length) {
        console.log(input);
        parsed += input[0];
        input = input.slice(1);
    }
    return <Token>{
        success: true,
        value: parsed,
        rest: input,
        data: null,
        error: null
    };
};

const combine_parser = (parsers: ParserFn[]): ParserFn => (input: string): Token => {
    let next = input;
    let result = [];
    for (let i = 0; i < parsers.length; i++) {
        const parser: ParserFn = parsers[i];
        const parse_result: Token = parser(next);
        result.push(parse_result.value);
        next = parse_result.rest;
    }
    return <Token>{
        success: true,
        value: result.join(''),
        rest: next,
        data: null,
        error: null
    };
};

let input = "*** Header";
console.log(combine_parser([match_char('*'), match_char('*'), match_char('*'), match_any_char_to_eol()])(input));