NAME

       "Commandable::Output" - abstractions for printing output from commands

DESCRIPTION

       This package contains default implementations of methods for providing printed output from commands
       implemented using Commandable. These methods are provided for the convenience of user code, and are also
       used by built-in commands provided by the "Commandable" system itself.

       Implementations are permitted (encouraged, even) to replace any of these methods in order to customise
       their behaviour.

   WITH "String::Tagged"
       If String::Tagged and Convert::Color are available, this module applies formatting to strings by using
       the String::Tagged::Formatting conventions.  The "format_heading" and "format_note" methods will return
       results as instances of "String::Tagged", suitable to pass into the main "printf" method.

METHODS

   printf
          Commandable::Output->printf( $format, @args )

       The main output method, used to send messages for display to the user. The arguments are formatted into a
       single string by Perl's "printf" function.  This method does not append a linefeed. To output a complete
       line of text, remember to include the "\n" at the end of the format string.

       The default implementation writes output on the terminal via STDOUT.

       In cases where the output should be sent to some other place (perhaps a GUI display widget of some kind),
       the application should replace this method with something that writes the display to somewhere more
       appropriate. Don't forget to use "sprintf" to format the arguments into a string.

          no warnings 'redefine';
          sub Commandable::Output::printf
          {
             shift; # the package name
             my ( $format, @args ) = @_;

             my $str = sprintf $format, @args;

             $gui_display_widget->append_text( $str );
          }

       If String::Tagged::Terminal is available, the output will be printed using this module, by first
       converting the format string and arguments using "from_sprintf" in String::Tagged and then constructing a
       terminal string using "new_from_formatting" in String::Tagged::Terminal. This means the default
       implementation will be able to output formatted strings using the String::Tagged::Formatting conventions.

   print_heading
          Commandable::Output->print_heading( $text, $level )

       Used to send output that should be considered like a section heading.  $level may be an integer used to
       express sub-levels; increasing values from 1 upwards indicate increasing sub-levels.

       The default implementation formats the text string using "format_heading" then prints it using "printf"
       with a trailing linefeed.

   format_heading
          $str = Commandable::Output->format_heading( $text, $level )

       Returns a value for printing, to represent a section heading for the given text and level.

       The default implementation applies the following formatting if "String::Tagged" is available:

       Level 1
           Underlined

       Level 2
           Underlined, cyan colour

       Level 3
           Bold

   format_note
          $str = Commandable::Output->format_note( $text, $level )

       Returns a value for printing, to somehow highlight the given text (which should be a short word or
       string) at the given level.

       The default implementation applies the following formatting if "String::Tagged" is available:

       Level 0
           Bold, yellow colour

       Level 1
           Bold, cyan colour

       Level 2
           Bold, magenta colour

AUTHOR

       Paul Evans <leonerd@leonerd.org.uk>