Translators

• Translator

  A program that converts code from one language into equivalent code written in another
• All code needs to be translated to machine code in order to be executed by a computer
• Main types of translators

  • Assembler
  • Compiler
  • Interpreter
• Assembler

  1. Takes assembly code

  2. Converts to machine code

  3. Output is an object file
• Assembly code


  • One-to-one nature with machine code
  • Optimization like replacing subroutine calls with inline functions
  • Evaluating constants
• Assembly code is used when memory and processing power are at a premium, e.g. in embedded devices
• Compiler

  1. Scans through whole code

  2. Translates to machine code

  3. Produces an executable binary file
• Compiler

  • Error messages only shown after scanning whole code
  • Compilation can take significant time for large programs
• Interpreter

  1. Translates and executes line by line

  2. Needs both interpreter and source code to run
• Interpreter

  • Slower than compiler
  • Provides instant feedback on errors
• Modern translators can be more complicated, using a mix of interpretation and compilation for optimization
• Bytecode

  Intermediate code that can be run by a virtual machine
• Object code

  Machine code plus extra instructions