[Bioperl-l] Generalized _setparams proposal

[Chris Fields]

Sendu,

Looks great to me!  As with your former proposed Bio::Root::RootI method,
would you switch run modules over to using this, or leave them be?

chris

> Bioperl-run wrappers (and some other modules) typically store 
> parameters from the user intended for the program they wrap 
> via methods of similar name to the parameter. The wrappers 
> then implement their own way of taking the values of those 
> methods and generating a parameter string suitable for 
> passing to the program.
> 
> Typically this is done in a _setparams() method with code 
> along the lines of:
> 
> $param_string .= ' --param_x '.$self->param_x if $self->param_x;
> 
> or a number of modules have their own variation on:
> 
> # clustalw's _setparam method
> my $param_string = "";
> for  $attr ( @CLUSTALW_PARAMS ) {
>    $value = $self->$attr();
>    next unless (defined $value);
>    my $attr_key = lc $attr; #put params in format expected by clustalw
>    $attr_key = ' -'.$attr_key;
>    $param_string .= $attr_key.'='.$value; } #...
> 
> 
> I propose generalizing this into a _setparams method in 
> Bio::Tools::Run::WrapperBase, eg. such that the above could 
> be re-implemented as:
> 
> # clustalw's _setparam method
> my $param_string = $self->SUPER::_setparam(
>    -methods => \@CLUSTALW_PARAMS,
>    -dash => 1,
>    -lc => 1,
>    -join => '=');
> #...
> 
> 
> 
> Proposed code follows:
> 
> =head2  _setparams()
> 
>   Title   : _setparams
>   Usage   : $params = $self->_setparams(-methods => [qw(window 
> evalue_cutoff)])
>   Function: For internal use by wrapper modules to build 
> parameter strings
>             suitable for sending to the program being 
> wrapped. For each method
>             name supplied, calls the method and adds the 
> method name (as modified
>             by optional things) along with its value (unless 
> a switch) to the
>             parameter string
>   Example : $params = $self->_setparams(-methods => 
> [qw(window evalue_cutoff)],
>                                         -double_dash => 1,
>                                         -underscore_to_dash => 1);
>             If window() had not been previously called, but
> evalue_cutoff(0.5)
>             had been called, $params would be ' --evalue-cutoff 0.5'
> 
>             A separate call should be used for methods that 
> store values that
>             are intended to be valueless switches:
> 
>             $params .= $self->_setparams(-methods => 
> [qw(simple large all)],
>                                          -switches => 1,
>                                          -double_dash => 1,
>                                          -underscore_to_dash => 1);
>             If simple() had not been called, large(1) had 
> been called and all(0)
>             had been called, $params would now be ' 
> --evalue-cutoff 0.5 --large'
> 
>   Returns : parameter string
>   Args    : -methods => [] or {} # REQUIRED, array ref of 
> method names 
> to call,
>                                    or hash ref where keys are 
> method names and
>                                    values are how those names 
> should be output
>                                    in the params string
>             -join => string      # define how parameters and their 
> values are
>                                    joined, default ' '. (eg. 
> could be '=' for
>                                    param=value)
>             -switches => boolean # all supplied methods are 
> treated as switches
>             -lc => boolean       # lc() method names prior to 
> output in 
> string
>             -dash => boolean     # prefix all method names 
> with a single 
> dash
>             -double_dash => bool # prefix all method names 
> with a double dash
>             -underscore_to_dash => boolean # convert all 
> underscores in method
>                                              names to dashes
> 
> =cut
> 
> sub _setparams {
>      my ($self, @args) = @_;
> 
>      my ($methods, $switch, $join, $lc, $d, $dd, $utd) =
>          $self->_rearrange([qw(METHODS
>                                SWITCHES
>                                JOIN
>                                LC
>                                DASH
>                                DOUBLE_DASH
>                                UNDERSCORE_TO_DASH)], @args);
>      $self->throw('-methods is required') unless $methods;
>      $self->throw("-dash and -double_dash are mutually 
> exclusive") if ($d && $dd);
>      $join ||= ' ';
> 
>      my %methods = ref($methods) eq 'HASH' ? %{$methods} : 
> map { $_ => $_ } @{$methods};
> 
>      my $param_string = '';
>      while (my ($method, $method_out) = each %methods) {
>          my $value = $self->$method();
>          next unless (defined $value);
>          next if ($switch && ! $value);
> 
>          $method_out = lc($method_out) if $lc;
>          $method_out = '-'.$method_out if $d;
>          $method_out = '--'.$method_out if $dd;
>          $method_out =~ s/_/-/g if $utd;
> 
>          $param_string .= ' '.$method_out.($switch ? '' : 
> $join.$value);
>      }
> 
>      return $param_string;
> }
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