good idea. I find prompting annoying though. Perhaps after the scaffold site is generate it can state:

Now run your application with the command: "yesod devel"
Just a warning: "yesod devel" will install this cabal package in your cabal database.

On Mon, Apr 18, 2011 at 5:55 PM, Felipe Almeida Lessa <felipe.lessa@gmail.com> wrote:
On Mon, Apr 18, 2011 at 9:40 PM, Greg Weber <greg@gregweber.info> wrote:
> I agree that this isn't optimal (and should be avoided in the long-term),
> but is it problematic in practice? It seems that the main problem would be
> if the name conflicted with an existing one- but we are willing to put the
> burden on the user to create a unique package name.

I just think that somehow the user should be warned that the package
is going to be installed.  Something like

 $ ls .yesod_devel_accepted
 ls: cannot access .yesod_devel_accepted: No such file or directory
 $ yesod devel
 This opereration needs to install your package to the user database.
 Do you want to proceed?  You will not be asked again.
 Proceed? (y/N)   y
 ...
 $ ls .yesod_devel_accepted
 .yesod_devel_accepted
 $ yesod devel
 ...

Cheers,

--
Felipe.