Class: Listener

Inherits:
Object
  • Object
show all
Defined in:
lib/linmeric/Listener.rb

Overview

This class works on the command line interface to allow the user to move the cursor, modify the input string in each point and retrieve commands from the history

Author

Massimiliano Dal Mas ([email protected])

License

Distributed under MIT license

Constant Summary collapse

CSI = 
"\e["
LETTERS = 
Tool.letters
NUMBERS = 
"0123456789"
SPECIAL_CHARS = 
"|!$%&/()=?'^~+-*<>-_,:;. " + '"'
CHARS = 
LETTERS + LETTERS.upcase + SPECIAL_CHARS + NUMBERS

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Listener

Creates the main variables



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# File 'lib/linmeric/Listener.rb', line 23

def initialize
  @final_string = ""
  @i = 0
  @s = 0
  @exit = false
  @list = Archive.new
end

Instance Method Details

#collect_single_key ⇒ Object

according to the collected key decides what to do: moving the cursor, surfing the history, or simply store chars in a variable



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# File 'lib/linmeric/Listener.rb', line 57

def collect_single_key()
  c = read_char
  case c
    
    # "TAB"
    when "\t"        
    
    # "RETURN"
    when "\r"
      puts c
      @exit = true
    when "\n"
      # "LINE FEED"
    when "\e"
      # "ESCAPE"
  
    # "UP ARROW"
    when "\e[A"      	
      temp = @list.previous
      unless temp == ""
        clear_line
        @final_string = temp
        @i = @final_string.size
        print @final_string
      end
      
    # "DOWN ARROW"    
    when "\e[B" 
        clear_line
        @final_string = @list.next_
        @i = @final_string.size
        print @final_string

    # "RIGHT ARROW"
    when "\e[C"
      @list.top
      unless @i == @final_string.size
        $stdout.write "#{CSI}1C"
        @i += 1
      end 
    
    # "LEFT ARROW"  
    when "\e[D"
      @list.top
      unless @i == 0
        $stdout.write "#{CSI}1D" 
        @i -= 1
      end
   
    # Delete char 
    when "\177" 
      @list.top
      unless @i == 0
        $stdout.write "#{CSI}1D"
        for i in (@i)...@final_string.size do
          $stdout.write "#{@final_string[i]}"
        end
        $stdout.write " "
        @final_string = @final_string.remove(@i-1)
        for i in (@i-2)...@final_string.size do
          $stdout.write "#{CSI}1D"
        end
        @i -= 1
      end

    when "\004"
      # "DELETE"
    when "\e[3~"
      # "ALTERNATE DELETE"
    
    # "Ctrl + C"
    when "\u0003"        
#        puts
#        exit 0
    when /^.$/
      @list.top
      if CHARS.include? c
        if @i < @final_string.size then
          last_i = @i + 2
          @final_string.insert @i, c
          clear_line
          $stdout.write "#{@final_string}"
          cursor_to(last_i)
          @i = last_i - 1
        else
          print c
          @final_string += c
          @i += 1
        end
      elsif c == "\f" then
        @i = 0
        print "\e[H\e[2J"
        print "Linmeric-main> "
      end
  end
end

#gets ⇒ Object

main function that can be used. It returns the stream the user wrote on the command line after they pressed return.



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# File 'lib/linmeric/Listener.rb', line 156

def gets()
  collect_single_key while(!@exit)
  @list.store(@final_string)
  return @final_string.clone
ensure
  reset
end

#read_char ⇒ Object

Reads a single char from the command line



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# File 'lib/linmeric/Listener.rb', line 39

def read_char
  STDIN.echo = false
  STDIN.raw!

  input = STDIN.getc.chr
  if input == "\e" then
    input << STDIN.read_nonblock(3) rescue nil
    input << STDIN.read_nonblock(2) rescue nil
  end
ensure
  STDIN.echo = true
  STDIN.cooked!

  return input
end

#reset ⇒ Object

reinitializates three main variables



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# File 'lib/linmeric/Listener.rb', line 32

def reset
  @final_string = ""
  @i = 0
  @exit = false
end