World's Simplest Code Generator: implemented in pure Javascript

Last night I was stuck using an old laptop, with no dev tools and no internet connection.

A machine without dev tools is like a pub without beer, i lamented, when i suddenly remembered Douglas Crockford's essay 'Javascript, the world's most misunderstood programming language.'

So I fired up notepad and set about re-writing "the world's simplest code generator" -- in pure javascript this time.

This was a fun and liberating exercise: programming without any tool support (remember Chucky Petzold's Does Visual Studio Rot The Mind?).

There were a few unexpected delights and challenges, that i'll talk about now. If you want to use (or bookmark) this new, faster version of the WSCG, i've polished it up a little and uploaded it to here:

world's simplest code generator (javascript edition)

function calculate() {
  //split the data into an array of rows
  var dataRows = $('txtData').value.split($('rowDelim').value);
  for (var i = 0; i < dataRows.length;i++) {
    //apply the pattern to each row
    result += apply($('txtPattern').value, dataRows[i], $('fieldDelim').value) + '\r\n';
  }
} 

function apply(pattern, row, fieldDelim) {
  //split the row into an array of fields
  var fields = rows.split(fieldDelim);
  for (var col = fields.length; col > 0; col --) {
    //replace '$1' with fields[0]... and so on for each field.
    //(applied in descending order, so that, for example, '$10' isn't mis-interpreted as '$1')
    pattern = pattern.replace(new RegExp('\\$' + col, "g") , trim(fields[col-1]));		 
  }   
  return pattern;
}

function ltrim(input) 
{
   //if it starts with spaces... remove them!
   return input.replace(/^\s+/gm,'')
}

function rtrim(input) 
{
   //if it ends with spaces... remove them!
   return input.replace(/\s+$/gm,'')
}

function trim(input) {
  //trim spaces from the front and the back of the string.
  return ltrim(rtrim(input));
}

  for (var col = fields.length; col > 0; col --) 

'Matt Casto' on Wed, 15 Aug 2007 10:26:39 GMT, sez:

Hurray! Another version of my favorite programming tool on the internet. You need to take away your internet access more often!

I hadn't seen that regex testing tool before. I've added it to my links and I'll find it helpful for quick regex verification. I usually use Regulator which I keep on a thumb drive. In fact, most of my development tools I have as portable application or installs stored on my thumb drive so I don't ever end up on a machine without any development tools.

'Des Traynor' on Wed, 15 Aug 2007 11:12:30 GMT, sez:

Nice work, I've been using WSCG for a while now.

I wrote a Javascript based Code to HTML converter, which has but a subset of your functionality. Basically you can throw any type of code into the first box, and you will get XHTML for it in the third box.
http://destraynor.com/c2h.html

'Simon' on Wed, 15 Aug 2007 13:15:52 GMT, sez:

You love it! I love the WSCG, and this does improve it one notch more. Well done.

'Andrew Webb' on Wed, 15 Aug 2007 14:06:18 GMT, sez:

Also on Javascript:

http://www.codinghorror.com/blog/archives/000857.html

'David Stone' on Wed, 15 Aug 2007 16:05:47 GMT, sez:

Javscript 1.7 actually has a foreach:

for(var x in myArray)
{
//yadda yadda yadda
}

Even works in IE 7. :)

'lb' on Wed, 15 Aug 2007 21:05:12 GMT, sez:

thanks for the feedback! glad to know the WSCG is still in use (i don't watch its traffic or usage... i used to but, gave up a while back)

I use it for all sorts of things myself.

@Des -- hey i've tinkered with that tool of yours. Some things I'd ask for, 1: a link on that page that tells us where to give feedback. 2: personally i'd like it if leading spaces get converted to non-breaking spaces. 3: I'm pretty wary of using the 'pre' tag as it stops a long line from wrapping which can destroy page layout/templates etc. 4: colour coding!! come on des! you can do it... only have to infer the language, and parse for all known operators/keywords/comment types etc. 5: compile the entered code and highlight any errors. 6: okay, number 5 went too far.

@David -- ah thanks!!

'Raj Chaudhuri' on Thu, 16 Aug 2007 06:36:57 GMT, sez:

You didn't mention wanting to do a CMD.EXE version, so I did one.

http://rajch.spaces.live.com/

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