Class: Mercury::CLI::Commands::Help

Inherits:
Cri::Command
  • Object
show all
Defined in:
lib/mercury/cli/commands/help.rb

Overview

Note:

This class is merely a helper class: the actual text, options and other details are drawn directly from the source code of those commands. In the execution of this command, we rely on the cri and cli libraries to do the hard work of actually processing the sub-commands.

The help command show the user a brief summary of the available sub-commands, and the short description of each of those commands.

Further help is available to the user, if one of the sub-commands is named as an argument to this command. In that case, the longer help for the command is displayed.

Author:

  • Denis Defreyne

  • David Love

Instance Method Summary collapse

Instance Method Details

#aliases ⇒ Object

The aliases this sub-command is known by



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# File 'lib/mercury/cli/commands/help.rb', line 41

def aliases
  []
end

#long_desc ⇒ Object

A longer description, detailing both the purpose and the use of this command



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# File 'lib/mercury/cli/commands/help.rb', line 52

def long_desc
  'Show help for the given command, or show general help. When no ' +
  'command is given, a list of available commands is displayed, as ' +
  'well as a list of global command-line options. When a command is ' +
  'given, a command description as well as command-specific ' +
  'command-line options are shown.'
end

#name ⇒ Object

The name of the sub-command (as it appears in the command line app)



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# File 'lib/mercury/cli/commands/help.rb', line 36

def name
  'help'
end

#run(options, arguments) ⇒ Object

Execute the command



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# File 'lib/mercury/cli/commands/help.rb', line 66

def run(options, arguments)
  # Check arguments
  if arguments.size > 1
    $stderr.puts "usage: #{usage}"
    exit 1
  end

  if arguments.length == 0
    # Build help text
    text = ''

    # Add title
    text << "A command-line tool for managing Mercury realms.\n"

    # Add available commands
    text << "\n"
    text << "Available commands:\n"
    text << "\n"
    @base.commands.sort.each do |command|
      text << sprintf("    %-20s %s\n", command.name, command.short_desc)
    end

    # Add global options
    text << "\n"
    text << "Global options:\n"
    text << "\n"
    @base.global_option_definitions.sort { |x,y| x[:long] <=> y[:long] }.each do |opt_def|
      text << sprintf("    -%1s --%-15s %s\n", opt_def[:short], opt_def[:long], opt_def[:desc])
    end

    # Display text
    puts text
  elsif arguments.length == 1
    command = @base.command_named(arguments[0])
    puts command.help
  end
end

#short_desc ⇒ Object

A short help text describing the purpose of this command



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# File 'lib/mercury/cli/commands/help.rb', line 46

def short_desc
  'Show help for a command'
end

#usage ⇒ Object

Show the user the basic syntax of this command



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# File 'lib/mercury/cli/commands/help.rb', line 61

def usage
  "mercury help [command]"
end