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From Michael J McGonagle <fnd...@rcnchicago.com>
Subject Re: Using the 'Uptodate' task
Date Fri, 15 Feb 2002 03:05:23 GMT
Diane Holt wrote:

Thanks Diane, I think my problem is that I am thinking of these as
"variables" and not properties. It is all in how the task interprets the
values of what is passed to them, it does not assume they are all
"variables" and try to evaluate them.

Mike

> 
> --- Michael J McGonagle <fndsnd@rcnchicago.com> wrote:
> > The problem turned out that I was using 'unless="${file3.isBuilt}"' when
> > it should have been 'unless="file3.isBuilt"'.
> >
> > Is it just a matter of the difference between testing for the
> > 'exsistance of' and getting the 'value of'?
> 
> Nope -- 'if' and 'unless' don't test the value of a property, only whether
> it's set/not-set.
> 
> > If this is the case, I can see why things were happening the way they
> > were with my original code. Both times it was getting a 'true' when it
> > tested for the property. On the one hand, it was true because the
> > variable was not set, and in the second, it is true because its VALUE
> > was true, and I was asking for its value and not its exsistance.
> 
> Nope -- you were saying "unless a property named '${file3.isBuilt}' is
> set, run this target". And since a property with that (literal) name
> wasn't set, your target ran. To see this try:
> 
> <!--  <property name="${foo}" value="true"/> -->
>   <target name="doUnless" unless="${foo}">
>     <echo message="Property $${foo} is not set."/>
>   </target>
>   <target name="doIf" if="${foo}">
>     <echo message="Property $${foo} is set."/>
>   </target>
> 
> $ ant doUnless doIf
> doUnless:
>      [echo] Property ${foo} is not set.
> 
> Now uncomment the <property/> and run it again. Of course, you'd never
> actually want to set a property that was named '${foo}', since you'd never
> be able to get at its value. (Maybe we should add some error-checking to
> prevent people from doing that very thing :)
> 
> Diane
> 
> =====
> (holtdl@yahoo.com)
> 
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