rpl.rb/repl.rb

# coding: utf-8
# frozen_string_literal: true

require "readline"

require "./lib/parser.rb"

module Rpn
  class Repl
    def initialize
      @parser = Parser.new
      @stack = []
    end

    def run
      Readline.completion_proc = proc do |s|
        directory_list = Dir.glob("#{s}*")
        if directory_list.positive?
          directory_list
        else
          Readline::HISTORY.grep(/^#{Regexp.escape(s)}/)
        end
      end
      Readline.completion_append_character = " "

      loop do
        input = Readline.readline( " ", true )
        break if input.nil? || input == "exit"

        # Remove blank lines from history
        Readline::HISTORY.pop if input.empty?

        process_input( input )

        print_stack
      end
    end

    def process_input( input )
      @parser.parse_input( input ).each do |elt|
        @stack << elt
      end
    end

    def format_element( elt )
      pp elt
      # case elt[:type]
      # when :program
      #   "« #{elt[:value]} »"
      # when :string
      #   "\"#{elt[:value]}\""
      # when :name
      #   "'#{elt[:value]}'"
      # else
        elt[:value]
      # end
    end

    def print_stack
      stack_size = @stack.size

      @stack.each_with_index do |elt, i|
        puts "#{stack_size - i}: #{format_element( elt )}"
      end
    end
  end
end

Rpn::Repl.new.run