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Posted to user@velocity.apache.org by Mike Kienenberger <mk...@alaska.net> on 2004/10/27 01:02:20 UTC

#set $var = (boolean exp) ==> $var = null

I suppose in retrospect since Velocity is String-oriented, this behavior is 
to be expected, but it sure seems counter-intuitive that

	#set ($listHasElements = ($list.size() > 0))
	#if ($listHasElements)

for lists containing elements does not work, but 

	#if ($list.size() > 0)

does.

Maybe my pointing this out will save someone else some pain.

-Mike

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Re: #set $var = (boolean exp) ==> $var = null

Posted by Mike Kienenberger <mk...@alaska.net>.
Shinobu Kawai <sh...@gmail.com> wrote:
> Well, here's what you /can/ do using 1.3:
> 
> #set ($listIsEmpty = $list.empty)
> #if ($listIsEmpty)
> no elements!
> #else
> first element : $list.get(0)
> #end
> 
> It looks like it's the expression that Velocity doesn't like, and not
> the Boolean.  (It didn't work for ... = !$list.empty)

Thanks for looking into it.

Fortunately, out of my hundreds of templates, I only used that construct 
once, and it was trivial to place it directly in the #if statement.

I never thought to check $list.empty, but that's a variable assignment, not 
a velocity boolean expression.

Probably the best news is that it's fixed in 1.4.

-Mike

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Re: #set $var = (boolean exp) ==> $var = null

Posted by Shinobu Kawai <sh...@gmail.com>.
Hi Mike,

> > #set ($listHasElements = ($list.size() > 0))
> > $listHasElements
> > 
> > should show "$listHasElements", right?  But it was "true".  It worked
> > for both 1.4 and CVS HEAD.
> > 
> > Maybe there's something wrong with your "$list".
> 
> Nope, but maybe the behavior changed in 1.4.  I'm using 1.3.1.
Yeah, I tried it on 1.3 and it failed.  ;)

Well, here's what you /can/ do using 1.3:

#set ($listIsEmpty = $list.empty)
#if ($listIsEmpty)
no elements!
#else
first element : $list.get(0)
#end

It looks like it's the expression that Velocity doesn't like, and not
the Boolean.  (It didn't work for ... = !$list.empty)

Best regards,
-- Shinobu Kawai

--
Shinobu Kawai <sh...@gmail.com>


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Re: #set $var = (boolean exp) ==> $var = null

Posted by Mike Kienenberger <mk...@alaska.net>.
Shinobu Kawai <sh...@gmail.com> wrote:
> Hi Mike,
> 
> > I suppose in retrospect since Velocity is String-oriented, this behavior 
is
> > to be expected, but it sure seems counter-intuitive that
> > 
> >        #set ($listHasElements = ($list.size() > 0))
> > 
> >        #if ($listHasElements)
> > 
> > for lists containing elements does not work, but
> > 
> >        #if ($list.size() > 0)
> > 
> > does.
> I wonder why it works in my environment?
> 
> #set ($listHasElements = ($list.size() > 0))
> $listHasElements
> 
> should show "$listHasElements", right?  But it was "true".  It worked
> for both 1.4 and CVS HEAD.
> 
> Maybe there's something wrong with your "$list".

Nope, but maybe the behavior changed in 1.4.  I'm using 1.3.1.

The list definitely exists and has elements.

-Mike

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Re: #set $var = (boolean exp) ==> $var = null

Posted by Shinobu Kawai <sh...@gmail.com>.
Hi Mike,

> I suppose in retrospect since Velocity is String-oriented, this behavior is
> to be expected, but it sure seems counter-intuitive that
> 
>        #set ($listHasElements = ($list.size() > 0))
> 
>        #if ($listHasElements)
> 
> for lists containing elements does not work, but
> 
>        #if ($list.size() > 0)
> 
> does.
I wonder why it works in my environment?

#set ($listHasElements = ($list.size() > 0))
$listHasElements

should show "$listHasElements", right?  But it was "true".  It worked
for both 1.4 and CVS HEAD.

Maybe there's something wrong with your "$list".

Best regards,
-- Shinobu Kawai

-- 
Shinobu Kawai <sh...@gmail.com>

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