R devel - May 2010 - require( "foo (>= 2.1)" )

Hello,

I often find myself writing code like :

if( require( "foo" ) && compareVersion( packageDescription( 
"foo")[["Version"]], "2.1" ) < 0 ){

	# code that uses version 2.1 of foo
} else {
	stop( "could not load version >= 2.1 of foo" )
}



Would it make sense to include something like this in require, library, 
etc ...

require( "foo (>= 2.1)" )
require( "foo", minimal.version = "2.1" )

I know we can use Depends: foo (>= 2.1) in a package DESCRIPTION file, 
but that does not work for loose dependencies, when package "bar"
works
better with "foo" but can still work fine without, or when not making
a
package.

Romain

-- 
Romain Francois
Professional R Enthusiast
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Hi Romain,

not that I have any authority here, but wouldn't your suggestion (which 
I think could be very useful) be more powerful if it were accompanied by 
a patch that could be applied to the R sources?

Best wishes
Wolfgang Huber
EMBL
http://www.embl.de/research/units/genome_biology/huber




On 28/05/10 19:25, Romain Francois wrote:
> Hello,
>
> I often find myself writing code like :
>
> if( require( "foo" ) && compareVersion(
packageDescription(
> "foo")[["Version"]], "2.1" ) < 0 ){
>
> # code that uses version 2.1 of foo
> } else {
> stop( "could not load version >= 2.1 of foo" )
> }
>
>
>
> Would it make sense to include something like this in require, library,
> etc ...
>
> require( "foo (>= 2.1)" )
> require( "foo", minimal.version = "2.1" )
>
> I know we can use Depends: foo (>= 2.1) in a package DESCRIPTION file,
> but that does not work for loose dependencies, when package "bar"
works
> better with "foo" but can still work fine without, or when not
making a
> package.
>
> Romain
>
--