[css-houdini-drafts] "computationally idempotent" is a bad term

dbaron has just created a new issue for 
https://github.com/w3c/css-houdini-drafts:

== "computationally idempotent" is a bad term ==
The [definition of 
<code>registerProperty()</code>](https://drafts.css-houdini.org/css-properties-values-api/#the-registerproperty-function)
 partially defines the term "computationally idempotent".

This term doesn't make sense because computation of all values of all 
CSS properties is idempotent.  Idempotence means that f(x) equals 
f(f(x)).  In this case we're talking about f() being the function 
compute() that produces a computed value from a specified value.  
Pretending for a moment that both the input and output of this 
function is strings (rather than a data type that we can convert to 
strings):  compute("1em") might well be "16px", but compute("16px") 
sure better be "16px".  Likewise, compute("inherit") may well be 
"rgb(0, 0, 255)" (depending on the property and the inherited value, 
of course), but compute("rgb(0, 0, 255)") sure better be "rgb(0, 0, 
255)".  (Gecko has tests to test this for a very large set of 
properties and values that we add to whenever we add support for new 
CSS values.)

Please view or discuss this issue at 
https://github.com/w3c/css-houdini-drafts/issues/282 using your GitHub
 account

Received on Tuesday, 23 August 2016 00:08:50 UTC