Module: Hammer::Shell

Included in:
Hammer
Defined in:
lib/hammer/shell.rb

Overview

ANSI color/output helpers. Mixed into command instances; also callable directly as ‘Hammer::Shell.say(…)`.

Defined Under Namespace

Classes: SayProxy

Class Method Summary collapse

Class Method Details

.ask(prompt, default: nil) ⇒ Object 



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# File 'lib/hammer/shell.rb', line 67

def ask(prompt, default: nil)
  suffix = default ? " [#{default}]" : ''
  print paint("#{prompt}#{suffix}: ", :cyan)
  line = $stdin.gets
  return default if line.nil?
  line = line.chomp
  line.empty? ? default : line
end

.choose(prompt, items) ⇒ Object

Arrow-key picker. Returns the chosen index, or nil on cancel (ESC, Ctrl-C, q). Non-TTY input falls back to a numbered prompt so this stays scriptable.

idx = choose 'Pick env', %w[dev staging prod]
say.green "chose #{ %w[dev staging prod][idx] }" if idx



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# File 'lib/hammer/shell.rb', line 88

def choose(prompt, items)
  items = items.to_a
  error 'choose needs at least one item' if items.empty?

  say.cyan prompt

  return choose_numbered(items) unless $stdin.tty? && $stdin.respond_to?(:raw)

  selected = 0
  redraw = lambda do |highlight = :cyan|
    items.each_with_index do |item, i|
      puts(i == selected ? paint("> #{item}", highlight) : "  #{item}")
    end
  end
  redraw.call

  $stdout.print "\e[?25l" # hide cursor
  begin
    $stdin.raw do |io|
      loop do
        ch = io.getch
        case ch
        when "\r", "\n"
          # Collapse the list to the chosen line, in green.
          $stdout.print "\e[#{items.size}A\e[J"
          puts paint("> #{items[selected]}", :green)
          return selected
        when "\x03", 'q' # Ctrl-C, q
          $stdout.print "\e[#{items.size}A\e[J"
          return nil
        when "\e"
          # ESC may stand alone or start an arrow sequence \e[A / \e[B.
          if IO.select([io], nil, nil, 0.01) && io.getch == '['
            case io.getch
            when 'A' then selected = (selected - 1) % items.size
            when 'B' then selected = (selected + 1) % items.size
            end
          else
            $stdout.print "\e[#{items.size}A\e[J"
            return nil
          end
        when 'k' then selected = (selected - 1) % items.size
        when 'j' then selected = (selected + 1) % items.size
        end
        $stdout.print "\e[#{items.size}A\e[J"
        redraw.call
      end
    end
  ensure
    $stdout.print "\e[?25h" # show cursor
  end
end

.choose_numbered(items) ⇒ Object

Fallback for non-TTY stdin (pipes, tests). Returns the index or nil.



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# File 'lib/hammer/shell.rb', line 142

def choose_numbered(items)
  items.each_with_index { |item, i| puts "  #{i + 1}) #{item}" }
  print paint("select [1-#{items.size}]: ", :cyan)
  line = $stdin.gets
  return nil if line.nil?
  idx = line.strip.to_i - 1
  idx.between?(0, items.size - 1) ? idx : nil
end

.color!(value) ⇒ Object 



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# File 'lib/hammer/shell.rb', line 20

def color!(value)
  @color = value
end

.color? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/hammer/shell.rb', line 15

def color?
  return @color if defined?(@color)
  @color = $stdout.tty? && ENV['NO_COLOR'].nil?
end

.error(text) ⇒ Object

Raise a controlled Hammer::Error. If unhandled, the dispatcher prints the message in red and exits 1 - no backtrace, no help spam.

error 'config file missing' unless File.exist?(path)

Raises:

  • (Hammer::Error) 


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# File 'lib/hammer/shell.rb', line 57

def error(text)
  raise Hammer::Error, text
end

.paint(text, color = nil) ⇒ Object 



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# File 'lib/hammer/shell.rb', line 24

def paint(text, color = nil)
  if color && !COLORS.key?(color)
    raise Hammer::Error, "unknown color #{color.inspect} (valid: #{COLORS.keys.join(', ')})"
  end
  return text.to_s unless color? && color
  "\e[#{COLORS[color]}m#{text}\e[0m"
end

.print_error(text) ⇒ Object

Print a red [error] line to stderr (does not exit). Used internally by the dispatcher to render Hammer::Error messages.



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# File 'lib/hammer/shell.rb', line 63

def print_error(text)
  warn paint("[error] #{text}", :red)
end

.say(text = nil, color = nil) ⇒ Object

‘say` with no args returns a proxy so you can write `say.cyan ’hi’‘. `say(”)` still prints a blank line; `say(’x’, :cyan)‘ is unchanged.



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# File 'lib/hammer/shell.rb', line 34

def say(text = nil, color = nil)
  return SayProxy.new if text.nil?
  puts paint(text, color)
end

.sh(cmd) ⇒ Object

Run a shell command. Echoes the command in gray, raises Hammer::Error on non-zero exit. Returns true on success.



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# File 'lib/hammer/shell.rb', line 153

def sh(cmd)
  say "$ #{cmd}", :gray
  error "command failed: #{cmd}" unless system(cmd)
  true
end

.yes?(prompt) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/hammer/shell.rb', line 76

def yes?(prompt)
  answer = ask("#{prompt} (y/N)")
  return false if answer.nil?
  answer.to_s.strip.downcase.start_with?('y')
end