[Mediawiki-l] parserfunctions question: evaluate vs. display?

[Brion Vibber]

Daniel Barrett wrote:
> In a parserfunctions statement like this:
> 
> {{#if:  {{#some-condition:}}  |  {{#some-big-computation:}} }}
> 
> if #some-condition is false, which of the following should happen?
> 
> 1.	#some-big-computation gets fully evaluated, but results are not
> displayed
> 2.	#some-big-computation is not evaluated at all

#2 (logical shortcut).

I can confirm this is how it works in both 1.12 and trunk (1.13 dev branch).

> Looks like choice #1 is happening in MW 1.12.0, which is bad if
> #some-big-computation has side-effects or is very expensive.  Is this
> correct behavior?

Are you perhaps running with the old parser enabled?

-- brion vibber (brion @ wikimedia.org)