codegen.js

const fs = require("fs");

const numberToLetters = (num) => {
	let letters = "";
	while (num >= 0) {
		letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"[num % 26] + letters;
		num = Math.floor(num / 26) - 1;
	}
	return letters;
};

const code =
	`
module [exampleFunction]

exampleFunction = \\x, y ->
    when x is
` +
	Array.from(Array(1000).keys())
		.map(
			(x) =>
				" ".repeat(8) +
				numberToLetters(x) +
				" ->\n" +
				" ".repeat(12) +
				"when y is\n" +
				Array.from(Array(1000).keys())
					.map(
						(y) =>
							" ".repeat(16) +
							numberToLetters(y) +
							" -> " +
							'"' +
							numberToLetters((x + 1) * (y + 1)) +
							'"',
					)
					.join("\n"),
		)
		.join("\n");

fs.writeFileSync("Example.roc", code);

main.roc

package [Example] {}