pry--pry/lib/pry/default_commands/context.rb

require "pry/default_commands/ls"

class Pry
  module DefaultCommands

    Context = Pry::CommandSet.new do
      import Ls

      command "cd", "Move into a new context (use `cd ..` to go back and `cd /` to return to Pry top-level). Complex syntax (e.g cd ../@x/y) also supported."  do |obj|
        path   = arg_string.split(/\//)
        stack  = _pry_.binding_stack.dup

        # special case when we only get a single "/", return to root
        stack  = [stack.first] if path.empty?

        resolve_failure = false
        path.each do |context|
          begin
            case context.chomp
            when ""
              stack = [stack.first]
            when "::"
              stack.push(TOPLEVEL_BINDING)
            when "."
              next
            when ".."
              unless stack.size == 1
                stack.pop
              end
            else
              stack.push(Pry.binding_for(stack.last.eval(context)))
            end

          rescue RescuableException => e
            output.puts "Bad object path: #{arg_string.chomp}. Failed trying to resolve: #{context}"
            output.puts e.inspect
            resolve_failure = true
            break
          end
        end

        next if resolve_failure

        _pry_.binding_stack = stack
      end

      command "switch-to", "Start a new sub-session on a binding in the current stack (numbered by nesting)." do |selection|
        selection = selection.to_i

        if selection < 0 || selection > _pry_.binding_stack.size - 1
          raise CommandError, "Invalid binding index #{selection} - use `nesting` command to view valid indices."
        else
          Pry.start(_pry_.binding_stack[selection])
        end
      end

      command "nesting", "Show nesting information." do
        output.puts "Nesting status:"
        output.puts "--"
        _pry_.binding_stack.each_with_index do |obj, level|
          if level == 0
            output.puts "#{level}. #{Pry.view_clip(obj.eval('self'))} (Pry top level)"
          else
            output.puts "#{level}. #{Pry.view_clip(obj.eval('self'))}"
          end
        end
      end

      command "jump-to", "Jump to a binding further up the stack, popping all bindings below." do |break_level|
        break_level = break_level.to_i
        nesting_level = _pry_.binding_stack.size - 1

        case break_level
        when nesting_level
          output.puts "Already at nesting level #{nesting_level}"
        when (0...nesting_level)
          _pry_.binding_stack.slice!(break_level + 1, _pry_.binding_stack.size)

        else
          max_nest_level = nesting_level - 1
          output.puts "Invalid nest level. Must be between 0 and #{max_nest_level}. Got #{break_level}."
        end
      end

      command "exit-all", "End the current Pry session (popping all bindings) and returning to caller. Accepts optional return value. Aliases: !!@" do
        # clear the binding stack
        _pry_.binding_stack.clear

        # break out of the repl loop
        throw(:breakout, target.eval(arg_string))
      end

      alias_command "!!@", "exit-all"

      command "exit", "Pop the current binding and return to the one immediately prior. Note this does NOT exit the program. Aliases: quit", :keep_retval => true do
        if _pry_.binding_stack.one?
          # when breaking out of top-level then behave like `exit-all`
          _pry_.binding_stack.clear
          throw(:breakout, target.eval(arg_string))
        else
          # otherwise just pop a binding
          popped_object = _pry_.binding_stack.pop.eval('self')

          # return a user-specified value if given
          if !arg_string.empty?
            target.eval(arg_string)
          else
            popped_object
          end
        end
      end

      alias_command "quit", "exit"

      command "exit-program", "End the current program. Aliases: quit-program, !!!" do
        Pry.save_history if Pry.config.history.should_save
        Kernel.exit target.eval(arg_string).to_i
      end

      alias_command "quit-program", "exit-program"
      alias_command "!!!", "exit-program"

      command "!pry", "Start a Pry session on current self; this even works mid multi-line expression." do
        target.pry
      end

      command "pry-backtrace", "Show the backtrace for the Pry session" do
        output.puts "\n#{text.bold('Backtrace:')}\n--\n"
        output.puts _pry_.backtrace
      end

      command "whereami", "Show the code context for the session. (whereami <n> shows <n> extra lines of code around the invocation line. Default: 5)" do |num|
        file = target.eval('__FILE__')
        line_num = target.eval('__LINE__')

        if num
          i_num = num.to_i
        else
          i_num = 5
        end

        if file != Pry.eval_path && (file =~ /(\(.*\))|<.*>/ || file == "" || file == "-e")
          raise CommandError, "Cannot find local context. Did you use `binding.pry`?"
        end

        set_file_and_dir_locals(file)

        method = Pry::Method.from_binding(target)
        method_description = method ? " in #{method.name_with_owner}" : ""
        output.puts "\n#{text.bold('From:')} #{file} @ line #{line_num}#{method_description}:\n\n"

        if file == Pry.eval_path
          f = Pry.line_buffer[1..-1]
        else
          unless File.readable?(file)
            raise CommandError, "Cannot open #{file.inspect} for reading."
          end
          f = File.open(file)
        end

        # This method inspired by http://rubygems.org/gems/ir_b
        begin
          f.each_with_index do |line, index|
            line_n = index + 1
            next unless line_n > (line_num - i_num - 1)
            break if line_n > (line_num + i_num)
            if line_n == line_num
              code =" =>#{line_n.to_s.rjust(3)}: #{line.chomp}"
              if Pry.color
                code = CodeRay.scan(code, :ruby).term
              end
              output.puts code
              code
            else
              code = "#{line_n.to_s.rjust(6)}: #{line.chomp}"
              if Pry.color
                code = CodeRay.scan(code, :ruby).term
              end
              output.puts code
              code
            end
          end
        ensure
          f.close if f.respond_to?(:close)
        end
      end

    end
  end
end