Files for autocomplete talk

auto-complete.org

Goal

• Introduce bash completion
• look at basic options
• build a custom completion

What’s out there

complete -p

complete -F _minimal
complete -F _fcoemon_options fcoemon
complete -o filenames -F _yu_yumdownloader yumdownloader
complete -o filenames -F _yu_builddep yum-builddep.py
...

299 on my home laptop

Setup

Register a completion strategy for a command.

Strategies all return lists of completions.

Setup Example: Function

complete -F _foo foo

Setup Example: Command

complete -C foo_comp foo

Setup Example: Actions

complete -A setopt set 

Setup Example: Options

complete -o filenames -o nospace -F _pass pass

Options

complete [-abcdefgjksuv] [-o comp-option] [-DEI] [-A action] [-G globpat]
[-W wordlist] [-F function] [-C command] [-X filterpat]
[-P prefix] [-S suffix] name [name …]
complete -pr [-DEI] [name …]

Example: SSH

complete -o default -o nospace -W \
  "$(awk '/^Host / {print $2}' < $HOME/.ssh/config)" scp sftp ssh;

More Complicated

Let’s build up a version for bk

We’ll use a dummy version called baker

baker

def pr cmd, options
  puts "'#{cmd} #{options.join(' ')}' was called"
end

cmd, *options = ARGV
case cmd
when 'up'
  pr cmd, options
when 'down'
  pr cmd, options
when 'runcmd'
 #....
else
  raise "Unknown cmd: #{cmd}"
end

version 1

#!/usr/bin/env ruby

# complete -r baker; complete -C ./c1.rb baker

COMMANDS = %w(up down runcmd ps pull version)

puts COMMANDS

exit 0

version 2

class BakerCompleter
  COMMANDS = %w(up down runcmd ps pull version)

  def self.completions(word)
    if word.empty?
      COMMANDS
    else
      COMMANDS.select do |c|
        c.match? word
      end
    end
  end
end

# baker <?>
full_cmd = ENV["COMP_LINE"].split
current_word = full_cmd.last.to_s.strip

puts BakerCompleter.completions(current_word)
exit 0

version 3

version 3

links

https://github.com/scop/bash-completion https://devmanual.gentoo.org/tasks-reference/completion/index.html https://debian-administration.org/article/317/An_introduction_to_bash_completion_part_2 https://blog.cykerway.com/posts/2016/12/23/how-to-write-bash-completion.html https://www.linuxjournal.com/content/more-using-bash-complete-command https://spin.atomicobject.com/2016/02/14/bash-programmable-completion/

baker

#!/usr/bin/env ruby

def pr cmd, options
  puts "'#{cmd} #{options.join(' ')}' was called"
end

cmd, *options = ARGV

case cmd
when 'up'
  pr cmd, options
when 'down'
  pr cmd, options
when 'runcmd'
  pr cmd, options
when 'ps'
  pr cmd, options
when 'pull'
  pr cmd, options
when 'version'
  pr cmd, options
else
  raise "Unknown cmd: #{cmd}"
end

c1.rb

#!/usr/bin/env ruby

# complete -r baker; complete -C c1.rb baker

COMMANDS = %w(up down runcmd ps pull version)

puts COMMANDS

exit 0

c2.rb

#!/usr/bin/env ruby

# complete -r baker; complete -C c2.rb baker

class BakerCompleter
  COMMANDS = %w(up down runcmd ps pull version)

  def self.completions(word)
    if word.empty?
      COMMANDS
    else
      COMMANDS.select do |c|
        c.match? word
      end
    end
  end
end

# baker <?>
full_cmd = ENV["COMP_LINE"].split
full_cmd.shift # drop bakerq
current_word = full_cmd.last.to_s.strip

puts BakerCompleter.completions(current_word)
exit 0

c3.rb

#!/usr/bin/env ruby

# complete -r baker; complete -C c3.rb baker

class BakerCompleter
  COMMANDS = %w(up down runcmd ps pull version)
  APPS = %w(lello pince valve nile)
  OPTS = {
    'up' => ['--no-migrations'],
    'down' => ['--no-rm'],
    'runcmd' => ["--command", "--no-build"]
  }

  def initialize previous, current
    @previous, @current = previous, current
  end

  def completions
    return COMMANDS if @current.nil? && @previous.nil?
    return nil      if @current == 'version'

    if @previous.empty? && COMMANDS.include?(@current)
      return APPS
    end

    if COMMANDS.include?(@previous)
      if @current.match("-")
        matches(OPTS[@previous], @current)
      else
        matches(APPS, @current)
      end
    else
      matches(COMMANDS, @current)
    end
  end

  private

  def matches(haystack, needle)
    haystack.select{|c| c.match? needle }
  end
end

args = ENV["COMP_LINE"].split.compact
args.shift # drop baker
current = args.pop.to_s.strip
previous = args.pop.to_s.strip

puts BakerCompleter.new(previous, current).completions
exit 0