markov.ts

function markov<T>(findFirst: () => T[][], findNext: (previous: T) => T[][]): T[][] {
	function chooseRandom<T>(xs: T[]): T {
		return xs[Math.floor(Math.random() * xs.length)];
	}
	
	function last<T>(xs: T[]): T {
		return xs[xs.length - 1];
	}
	
	var result: T[][] = [];
	result.push(chooseRandom(findFirst()));
	while (true) {
		var previous = last(last(result));
		if (previous === null) {
			break;
		}
		var next = findNext(previous);
		if(next.length === 0) {
			break;
		}
		result.push(chooseRandom(next).slice(1));
	}
	return result;
}

(function() {
	var data: string[][] = [
		[null, "私", "は"],
		["私", "は", "りんご"],
		["は", "りんご", "が"],
		["りんご", "が", "好き"],
		["が", "好き", "だ"],
		["好き", "だ", null],
		[null, "彼", "は"],
		["彼", "は", "みかん"],
		["は", "みかん", "が"],
		["みかん", "が", "好き"],
		["が", "好き", "だ"],
		["好き", "だ", null]
	];
	
	var result = markov<string>(
		() => data.filter(xs => xs[0] === null),
		previous => data.filter(xs => xs[0] === previous));
	document.write(result.map(xs => xs.join('')).join(''));
})();