Execute Brain****/Ruby

Execute Brain****/Ruby is an implementation of Brainf***. Other implementations of Brainf***.

Execute Brain****/Ruby is part of RCBF. You may find other members of RCBF at Category:RCBF.

More effort could be made to read a program from a file or from stdin.

<lang ruby>class RCBF

 def initialize(program)
   @d = [0] * 30_000
   @program = program
   @jumpback_table = read_program
 end
 
 def read_program
   jumpback_table = {}
   nest_level = 0
   start_idx = []
   @program.each_char.each_with_index do |char, idx|
     case char
     when "["
       start_idx[nest_level] = idx
       nest_level += 1
     when "]"
       nest_level -= 1
       jumpback_table[idx] = start_idx[nest_level]
     end
   end
   jumpback_table
 end

 def run
   dc = 0
   pc = 0
   while pc < @program.length
     print [pc, @program[pc].chr].inspect if $DEBUG

     case @program[pc]
     when ?> 
       dc += 1
       print "\t#{dc}" if $DEBUG
     when ?< 
       dc -= 1
       print "\t#{dc}" if $DEBUG
     when ?+ 
       @d[dc] += 1
       print "\t#{dc},#{@d[dc]}" if $DEBUG
     when ?- 
       @d[dc] -= 1
       print "\t#{dc},#{@d[dc]}" if $DEBUG
     when ?. 
       print "\t#{dc},#{@d[dc]}\t" if $DEBUG
       print @d[dc].chr
     when ?, then
       @d[dc] = $stdin.getc
       print "\t#{dc},#{@d[dc]}" if $DEBUG
     when ?[ then
       if @d[dc] == 0
         pc = @jumpback_table.invert[pc]
         p "  #{[pc,@program[pc].chr].inspect}" if $DEBUG
       end
     when ?] then
       if @d[dc] != 0
         pc = @jumpback_table[pc]
         p "  #{[pc,@program[pc].chr].inspect}" if $DEBUG
       end
     end
     puts if $DEBUG
     pc += 1
   end
 end

end

1. output 'Hello World!\n'

helloworld = <<PROGRAM ++++++++++[>+++++++>++++++++++>+++>+<<<<-] >++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>. PROGRAM bf = RCBF.new(helloworld) bf.run

1. use nested loop to increment count to 64 and print (should be '@')"
2. 64 = 4*4*4

nestedloop = '>>++++[<++++[<++++>-]>-]<<.[-]++++++++++.' bf = RCBF.new(nestedloop) bf.run</lang>

Output:

Hello World!
@