====== Alternatives to compilation? ======

===== Interpreter =====

A program that reads source code and directly executes it
  * does not generate the translation of the source program first

{{cc09:interpreter.png|Interpreter}}

===== Compiler =====

{{cc09:compiler-purpose.png|}}

Advantages of **compilers** over interpreters:
  * once compiled, execution can be much faster
     * 'carefully prepare' program for fast execution 
  * better semantic checks: examine the entire program
    and report errors before program is run

This is our topic.

===== Just-in-time compiler ===== 

{{cc09:jit-purpose.png|}}

e.g. Java virtual machine and .NET virtual machine
  * starts by interpreting the program
  * later compiles the parts where speed is critical

At the end of course, we will say a few words about 
  * Java virtual machine, e.g. [[wp>garbage collection (computer science)|memory management]]