Programming Languages / Translators

Programming Languages / Translators

• 1.
  Computer Science (A Level) Programming Languages
• 2.
  Programmed code thathas not yet been compiled into an executable file General name for any program that translates code from one language to another (Definitions)
• 3.
  A program thattranslates a high–level language into machine code by translating all of the code Compiled code that can be run as an executable on any computer (Definitions)
• 4.
  A program thattranslates a high–level language by reading each statement in source code and immediately performing the action A program that translates a program written in assembly language into machine code (Definitions)
• 5.
  • The assemblycode is known as source code and this is translated into object code (compiled code) by an assembler. • Before assembly code can be executed it must be translated into the equivalent machine code. This is done by an assembler. • The assembler program takes each assembly code instruction and converts it into the corresponding 0s and 1s. • The input is called source code and the output is called object code. Assembler
• 6.
  • A compileris a program that translates high-level language (e.g. C++, Visual Basic etc.) into machine code. • Source code is written by the programmer and input to the compiler. It scans through several times , each time performing different checks and building up tables of information to produce the final object code. • Different hardware platforms (Intel, Apple, etc.) require different compilers. • The object code (executable machine code) can be saved and run without needing the compiler Compiler
• 7.
  Compiler Advantages Disadvantages • Objectcode can be saved to disk and run when required • If an error have to recompile whole program • Executes faster • Will only run on a computer that has the same platform • Object code can be distributed or executed without the compiler • You cannot change the program without going back to the source code • Secure as object code cannot be read without reverse engineering • The translation is only done once and as a separate process • Compiled programs can run on any computer
• 8.
  • An interpreterreads a statement of the source code and immediately performs the required action. • Once the programmer has written and saved a program and instructs the computer to run it the interpreter looks at each line in the source code analyses it and if there no errors translates it into machine code. Interpreter
• 9.
  Interpreter Advantages Disadvantages • Usefulfor program development as there is no lengthy recompilation • The program may run slower because each statement has to be translated every time it is encountered • Easier to partially test and debug programs • Need to have the interpreter installed (Interpreted programs can only run on computers that have the interpreter) • Can be run on different hardware platforms • Source code must be provided to users • Easier to use • You can interrupt it while it’s running, change the program and either continue or start again.
• 10.
  An instruction setused for programming that can be executed on any computer using a virtual machine (Definitions)
• 11.
  • Most interpretedlanguages (e.g. python or Java) use an intermediate representation that combines compiling and interpreting called bytecode • This is an instruction set that can be executed using a virtual machine (the bytecode interpreter) which emulates the architecture of a computer. • It is platform independent as long as the bytecode interpreter is installed • Bytecode can be either compiled once and for all (e.g. Java) or each time the source code changes before execution (e.g. python) Bytecode