140byt.es -- Click ↑↑ fork ↑↑ to play!

README.md

140byt.es

A tweet-sized, fork-to-play, community-curated collection of JavaScript.

How to play

1. Click the button above to fork this gist.
2. Modify all the files to according to the rules below.
3. Save your entry and tweet it up!

Rules

All entries must exist in an index.js file, whose contents are

1. a valid Javascript function expression, that
2. optionally self-executes,
3. contains no more than 140 bytes, and
4. does not pollute global scope.

All entries must also be licensed under the MIT license.

For more information

The 140byt.es site hasn't launched yet, but for now follow @140bytes on Twitter.

140byt.es is brought to you by Jed Schmidt. It was inspired by work from Thomas Fuchs and Dustin Diaz.

annotated.js

updatePhysicsUsingPseudoCalculusTimeForJedsTweetThingie // meaningful name.
= function
  ( a // the entity, some set of [[x,y,z],[dx,dy,dz],[ddx,ddy,ddz],...]
  , b // elapsed time

      // local variables:
  , c // counter for the set of derivatives
  , d // variable for each set of derivatives
  , e // variable for each derivative in a set
  , f // counter for the derivative in a set
  , g // undefined
  , h // the previous set of derivatives
  ) {

    f=c=0 // initialize counters
    while // loop over the set of derivatives
      ( d = a[ h=c, ++c ]) // while also getting a reference to the previous
                           // item in the set, and incrementing the counter
                           // so that it starts at 1, but h=0
      while ((e = d[f]) != g) // over each dimension derivative != undefined
        a[h][f++] += e*b // update the appropriate dimension, and
                         // increment the dimension counter
  }

index.js

updatePhysicsUsingPseudoCalculusTimeForJedsTweetThingie=function(a,b,c,d,e,f,g,h){f=c=0;while(d=a[h=c,++c])while((e=d[f])!=g)a[h][f++]+=e*b}

LICENSE.txt

Copyright (c) 2011 YOUR_NAME_HERE, YOUR_URL_HERE
 
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
 
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

package.json

{
  "name": "physics-updater",

  // [OPTIONAL] A description of your library, phrased as a verb predicate.
  // The gist description is used by default.
  "description": "Update an entity based on d/dt values and elapsed time",

  // [OPTIONAL] Up to 5 keywords used for indexing.
  "keywords": [
    "physics", "calculus"
  ]
}

the byte you save could be your own.

function(a,b,c,d,e,f,g,h){for(f=c=0;d=a[h=c,++c];)while((e=d[f])!=g)a[h][f++]+=e*b}

Oh, nice. Then you don't need the \n for the loop initializers.

Is this Euler's Method in 140 bytes? o_o Hard core.

Edit: Oh, no, because it takes in precalc'd derivatives. But Euler's Method would be pretty neat!