{"id":25,"date":"2008-03-21T23:06:39","date_gmt":"2008-03-22T04:06:39","guid":{"rendered":"http:\/\/littlesvr.ca\/grumble\/2008\/03\/21\/to-sleep-with-javascript\/"},"modified":"2012-12-05T00:57:41","modified_gmt":"2012-12-05T05:57:41","slug":"to-sleep-with-javascript","status":"publish","type":"post","link":"http:\/\/littlesvr.ca\/grumble\/2008\/03\/21\/to-sleep-with-javascript\/","title":{"rendered":"To sleep with javascript"},"content":{"rendered":"

All proper programming languages I can think of have a real simple function – sleep(). It suspends the execution of your program for a time. This is what I wanted to do. Having no choice but to use javascript in this case, I went around looking for what the sleep() function is called in this dreadful language.<\/p>\n

Turns out there is none. There is only setTimeout() and setInterval(). Either will call a function after a time, but in between your code will continue to execute.<\/p>\n

All I could find on the internet is a bunch of solutions to this problem involving an infinite loop. That, for I hope obvious reasons, was not acceptable for me.<\/p>\n

I considered using `yield` but that doesn’t work for some reason in my version of the current firefox trunk. I did the javascript version thing, but then none of the javascript I had (yield or not) would work at all.<\/p>\n

So I grumbled for a couple of hours and finally figured out a solution so my stuff still works as I want it, and all that’s lost is readability. I’ll share this beast with you all in case you ever run into the same problem.<\/p>\n

This is what I wanted done in the first place, overly simplfied (lack of whitespace courtesy of wordpress):<\/p>\n

function wish(i, j)
\n{
\nvar k = i + j;<\/p>\n

for(var m = 0; m < 10; m++)
\n{
\n\/\/ start doing something outside of my control<\/p>\n

sleep(5000); \/\/ sleep for 5 seconds<\/p>\n

\/\/ check the results of the something<\/p>\n

alert(k + “, ” + m + results);
\n}
\n}<\/p>\n

Like I said, it’s overly simplified. There’s no need to bring 3D and benchmarks into this example.<\/p>\n

Since setInterval() is all I have to work with, that’s what I’ll use. The tricks to address my concerns are:<\/p>\n

    \n
  1. Make a global function that will take the (i, j) parameters and have it call another function (real()) that doesn’t take any parameters<\/li>\n
  2. Copy the parameters to wish() into glabal variables<\/li>\n
  3. Where the sleep() would be have a setInterval(‘real()’, 5000) instead<\/li>\n
  4. Copy all the local variables in real() to global variables before the setInterval()<\/li>\n
  5. Add a condition so real() will know whether it should continue from where it left off or start from the beginning.<\/li>\n<\/ol>\n

    A lot of work, but the other option is to not do it at all.. Here’s what it now looks like:<\/p>\n

    var gI;
    \nvar gJ;<\/p>\n

    function wish(i, j)
    \n{
    \ngI = i;
    \ngJ = j;
    \nreal();
    \n}<\/p>\n

    var gK;
    \nvar gM = 0;
    \nvar didSleep = false;<\/p>\n

    function real()
    \n{
    \nif (didSleep)
    \n{
    \n\/\/ check the results of the something
    \nalert(gK + “, ” + (gM – 1) + results);
    \n}
    \nelse
    \n{
    \ngK = gI + gJ;
    \n}<\/p>\n

    for(m = gM; m < 10; m++)
    \n{
    \n\/\/ start doing something outside of my control<\/p>\n

    gK = k;
    \ngM = m + 1;
    \ndidSleep = true;
    \nsetInterval(“real()”, 5000);
    \nreturn;
    \n}
    \n}<\/p>\n

    That’s pretty disgusting. I’d blame the people who came up with javascript if it wasn’t for the fact that javascript was never designed to be a proper language. Javascript was made for people one level above HTML, which is far, far from real programming and it served those people well.<\/p>\n

    Instead I blame the people responsible for the javascript hype. Both the fanboys who don’t know any better but their strength is in numbers; and the programmers who sell their time\/ideas by proclaiming that AJAX is the only way to go. I even blame google a little for making the two useful javascript applications in the world.<\/p>\n

    I’ll say it again – disgusting.<\/p>\n","protected":false},"excerpt":{"rendered":"

    All proper programming languages I can think of have a real simple function – sleep(). It suspends the execution of your program for a time. This is what I wanted to do. Having no choice but to use javascript in this case, I went around looking for what the sleep() function is called in this … <\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":{"0":"entry","1":"post","2":"publish","3":"author-andrew","4":"post-25","6":"format-standard","7":"category-safeforseneca"},"_links":{"self":[{"href":"http:\/\/littlesvr.ca\/grumble\/wp-json\/wp\/v2\/posts\/25","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/littlesvr.ca\/grumble\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/littlesvr.ca\/grumble\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/littlesvr.ca\/grumble\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"http:\/\/littlesvr.ca\/grumble\/wp-json\/wp\/v2\/comments?post=25"}],"version-history":[{"count":2,"href":"http:\/\/littlesvr.ca\/grumble\/wp-json\/wp\/v2\/posts\/25\/revisions"}],"predecessor-version":[{"id":670,"href":"http:\/\/littlesvr.ca\/grumble\/wp-json\/wp\/v2\/posts\/25\/revisions\/670"}],"wp:attachment":[{"href":"http:\/\/littlesvr.ca\/grumble\/wp-json\/wp\/v2\/media?parent=25"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/littlesvr.ca\/grumble\/wp-json\/wp\/v2\/categories?post=25"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/littlesvr.ca\/grumble\/wp-json\/wp\/v2\/tags?post=25"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}