CASSIS
Tantek Çelik tantek.com • @t
2008
Bulletproof AJAX
more responsive =
better UX
href="#"
breaks the web
href="?p=jeremy"
+ Unobtrusive JavaScript
"Hijax"
Unobtrusive AJAX
writing code twice:
JavaScript & PHP
DRY principle
(Don't Repeat Yourself)
tired of rewriting in different languages
can we pick a winner?
has JavaScript (JS) won?
(yet)
most # of programmers
most # of companies optimizing it
JS on client & server
= write logic once
JS subset that works
on client & server?
CASSIS conceived
- Client
- And
- Server
- Scripting
- Implementation
- Subset
avoid unintentionally enabling SkyNet
JS on the server
not supported by default
but all web hosts run PHP
intersection of JS & PHP?
2009
falsy values research
false 0 "0" "00"
falsy value testing
function js() {
return ("00"==false);
}
function js() {
return ("00"==false);
}runtime switching good
need a parsetime switch
2001
voice-family:"\"}\"";
2002
Semantic Scripting
principle of separation of script and markup
hypertext script docs
external JS with HTML
<!-- /*-->
markup ...
<!--*/ //-->
script
//<!--
/*-->
more markup
<!--*/ //-->
<!-- /*-->
markup ...
<!--*/ //-->
script
//<!--
/*-->
more markup
<!--*/ //-->
but for JS and PHP files
back to 2009
CASSIS v0 code
<!-- <?php // -->
/* cassis.js v0 code */
/* valid JS and PHP */
// ?> -->
<!-- <?php // -->
/* cassis.js v0 code */
/* valid JS and PHP */
// ?> -->
<!-- HTML -->
<script src="cassis.js">
<!-- HTML -->
<script src="cassis.js">/* php */
ob_start();
include 'cassis.js';
ob_end_clean();
/* php */
ob_start();
include 'cassis.js';
ob_end_clean();
challenge: variable names
jQuery popularized $ in JS
CASSIS convention:
$ variables e.g. $x
challenge: string concat
'a'+'b' vs 'a'.'b'
common function instead
function strcat($s1,$s2) {
if (js()) {
return $s1 + $s2;
}
else {
return $s1 . $s2;
}
}
function strcat($s1,$s2) {
if (js()) {
return $s1 + $s2;
}
else {
return $s1 . $s2;
}
}
challenge: PHP-only code
date_default_timezone_set("UTC");
need a PHP-only block
/* <!-- <?php // -->
echo 'PHP only';
// */
/* both JS and PHP */
// ?> -->
/* <!-- <?php // -->
echo 'PHP only';
// */
/* both JS and PHP */
// ?> -->
challenge: JS-only code
e.g. PHP function equivalents
function strlen(s) {
return s.length;
}
function ord(s) {
return s.charCodeAt(0);
}
function strlen(s) {
return s.length;
}
function ord(s) {
return s.charCodeAt(0);
}
need JS and/or PHP
/*/
comment inverter
/**/
stateless comment closer
/* <!-- <?php // -->
echo 'PHP only';
/*/
alert("JS only");
/**/
/* both JS and PHP */
// ?> -->
/* <!-- <?php // -->
echo 'PHP only';
/*/
alert("JS only");
/**/
/* both JS and PHP */
// ?> -->
What's CASSIS good for?
- functional programming
- math, datetime computations
- string processing/parsing
- form validation routines