get a stochastic integer in range
This script should not be not be installed directly. It is a library for other scripts to include with the meta directive // @require https://update.greasyfork.org/scripts/430439/1074311/RandInt-Getter.js
// ==UserScript==
// @name RandInt-Getter
// @namespace http://greasyfork.org/
// @version 0.1
// @description get a stochastic integer in range
// @author Cosil.C
// @grant unsafeWindow
// @license GPLv3
// ==/UserScript==
/**
* @description get a stochastic integer in range
* @param exp pattern: [|( -* \d+ , -* \d+ )|]
* @returns a stochastic integer with type number in range
*/
unsafeWindow.getRandInt = (exp) => {
if ('string' != typeof exp) {
throw 'Expression param error: the param inputed must be a string';
}
if (!/[\[\(]\s*-{0,1}\s*\d+\s*,\s*-{0,1}\s*\d+\s*[\]\)]/.test(exp)) {
throw 'Expression syntax error';
}
let res;
exp.replace(/([\[\(])\s*(-{0,1}\s*\d+)\s*,\s*(-{0,1}\s*\d+)\s*([\]\)])/g, (rs, $1, $2, $3, $4) => {
let left = $1.charCodeAt(),
min = parseInt($2.replace(/\s+/, '')),
max = parseInt($3.replace(/\s+/, '')),
right = $4.charCodeAt();
if (min > max) {
throw `Expression param error: cause ${min} > ${max}`;
} else if (right - left == 1 && max <= min + 1) {
throw `Expression param error: cause range is '(' and ')' but can't found any integer between ${min} and ${max}`;
} else {
res = min + Math.floor(Math.random() * (max - min + (right == left + 2 ? 1 : right == left + 1 ? -1 : 0))) + (left == 40 ? 1 : 0);
}
})
return res;
}