PenisScript

main.lua

local instructions = {
  ['>'] = '8=D',
  ['<'] = '8==D',
  ['+'] = '8===D',
  ['-'] = '8====D',
  ['.'] = '8=====D',
  [','] = '8======D',
  ['['] = '8=======D',
  [']'] = '8========D'
}

local reversed_instructions = {}

for i, v in pairs(instructions) do
  reversed_instructions[v] = i
end

local function to_bf(program)
  program = program:gsub('[^8=D]', '')

  for i, v in pairs(reversed_instructions) do
    program = program:gsub(i, v)
  end

  return program
end

local function from_bf(program)
  program = program:gsub('[^><%+%-%.,%[%]]', '')

  for i, v in pairs(instructions) do
    program = program:gsub('%' .. i, v)
  end

  return program
end

local input = io.open(arg[2])
local program = input:read("a")
input:close()

if arg[1] == 'compile' then
  local output = io.open('out.bf', 'w')
  output:write(to_bf(program))
  output:close()
elseif arg[1] == 'reverse' then
  local output = io.open('out.pp', 'w')
  output:write(from_bf(program))
  output:close()
end

fuck