Re: [Nant-users] Re: Segfault during compilation with mono on Linux

[Ian MacLean]

Gert Driesen wrote:
-----Original Message-----
From: [EMAIL PROTECTED] 
[mailto:[EMAIL PROTECTED] On Behalf Of 
Ian MacLean
Sent: vrijdag 3 december 2004 9:29
To: Gert Driesen
Cc: 'Troy Laurin'; 'J. Christopher Six'; 
[EMAIL PROTECTED]
Subject: Re: [Nant-users] Re: Segfault during compilation 
with mono on Linux

Gert Driesen wrote:
   

This is a legacy of Ant not having expressions or an if 
    

         

statement, so 
  

       

the only way to conditionally perform tasks was via this 
         

depends/if 
   

mechanism:
<target name="foo" depends="foo-test" if="${foo-exists}">
<do-foo />
</target>
<target name="foo-test">
<available file="foo.txt" property="foo-exists" />
</target>
    

         

Since NAnt now does have expressions then that behaviour 
doesn't make as 
much sense. You can achieve the same thing by putting the if 
test inside 
the target. However with the current behaviour you *can't* 
prevent both 
a target and its dependencies from being executed just by 
using the "if" 
attribute. This seems like one case where diverging from Ants 
behaviour 
might not be a bad thing. Certainly the current behaviour 
violates the 
"principle of least suprise".
  

       

I understand, but it does make sense that dependencies can 
     

have influence on
   

whether or not the target should be executed.
     

they can anyway :
<target name="foo" depends="foo-test" >
	<if test="${foo-exists}" >
 		<do-foo />
	</if>
</target>
   

Ofcourse, but I prefer having the condition on the target (when possible).
 

however right now you *can't* stop a target  *and* all its 
dependencies 
from being run  by using the  if attribute - and that seems 
like a big  
functionality hole.
   

Yeah, I know ...
 

I think the "stop this target and all its dependencies from running" 
use-case is a more common one than the:

"stop only this target but let all its dependencies execute" one.
   

If you put it like that yes, but another common use-case is : "execute a
target, but have its dependencies decide whether tasks in that target should
indeed be executed"
 

yes and as I pointed out - that can be done with:
<target name="foo" depends="foo-test" >
        <if test="${foo-exists}" >
                <do-foo />
        </if>
</target>
ie the dependencies set the value of foo-exists.

If your first use-case is that common, then how come it has taken several
years for this to become an issue ? ;-)
 

fair point - I guess everyong has just worked around it up till now.
well - adding useful functionality seems like a pretty good reason - 
especially when the Ant behaviour is only there because they lack an 
expression system.
   

Is that indeed the reason ?
 

Troy seemed to think so. Maybe Stefan is reading and can offer his 
opinion. Personally I have no idea.

Sure - of course breaking compatibility is a bad thing generally - 
however in this case I think there are probably more users who are 
frustrated/confused by the current behaviour than are 
actively relying 
on it. I could be wrong though - I'd love to get peoples 
opinions on this.
   

Yeah, me too. I have no problem with this change, if our user base (and not
just one or two persons) agrees its for the best, and if the Ant developers
only implemented it like this because they do not have an expression system.
 

Excellent - we have reached agreement :)
should be secondary to having it do the 
right thing.
   

But we should at least make sure the new behavior is clearly documented, and
announced as a (major) breaking change (if we decide to change this
behavior).
 

totally - no argument there.
Ian

-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now. 
http://productguide.itmanagersjournal.com/
_______________________________________________
Nant-users mailing list
[EMAIL PROTECTED]
https://lists.sourceforge.net/lists/listinfo/nant-users