Re: [Module::Build] ask() and you will receive

[Ken W. <ke...@ma...>]

On Apr 14, 2006, at 4:44 AM, Randy W. Sims wrote:

> +
> +=item allow_nonoption_default
> +
> +Normally, the value of the C<default> arguement must exist in the
> +C<options> array.  Setting this to true allows the C<default>  
> argument
> +to be set to an arbitrary value.

I do still wonder about the need for this parameter.  The author  
could just as easily put the value in the options array, and probably  
with less typing.

Not a big deal, though.

Let's at least update the verbiage to read something like this,  
indicating that C<options> isn't required:

+=item allow_nonoption_default
+
+Normally, if an C<options> array is present, then the value of the  
C<default>
+argument must exist in C<options>.  Setting  
C<allow_nonoption_default> to true
+allows the C<default> argument to be set to an arbitrary value.



> +
> +=item default   [required]
> +
> +This is the default value that will be used if the user presses
> +E<lt>enterE<gt> or if running an unattended build.
> +
> +The value assigned to C<default> may be different from the options
> +listed in the C<options> argument.

I think I'm about to blaspheme, but I think sometimes we shouldn't  
require there to be a default.

/me ducks

Sometimes there's simply no way to build & test & install a module  
without user intervention.  For example, Inline::Java asks you to  
tell it where the J2SDK installation is, and there's no default.

If we changed the error message to something appropriate, I think we  
could handle this case gracefully, both here and in y_n().  Something  
like:

   if ( $ENV{PERL_MM_USE_DEFAULT} && !$def ) {
     die <<EOF;
ERROR: PERL_MM_USE_DEFAULT is in effect, but there is no default  
value.  Aborting.
EOF
   }

It might be nice to note this fact in the META.yml file, using a flag  
like 'interactive_install' or something, so that automated testers  
don't even try to download & build the distro.

For a distro that really requires interaction like this, the author  
could work around our proposed required 'default' by setting  
'default' to undef and then die()ing with their own error message if  
prompt() or y_n() or ask() returned undef, but why not provide them  
with the appropriate sugar?


> +A reference to an array containing a list of valid options.  If  
> options
> +are provided, C<ask()> will not return until a valid option is
> +entered, or the C<default> is selected by pressing E<lt>enterE<gt>
> +without entering a value.  Option names are case-insensitive, but the
> +option returned will be normalized to the form used in the  
> argument to
> +C<options>.  It is not necessary for the user to enter the entire
> +option name; C<ask()> will accept any unambiguous sequence of
> +characters that will match only one option.  Eg. If the options are
> +C<qw(yes no)> it will accept any of 'y', 'ye', or 'yes' to mean
> +yes.  The complete option name will be returned.

Maybe we should make this conditional on an option called  
'allow_abbrev', default true, or something?

  -Ken