Translators (OCR A Level Computer Science)

Translators

What is a Translator?

• Translators convert source code from a high-level language to a low-level language

• There are three main types of translators

  • Interpreters

  • Compilers

  • Assemblers

Interpreters

• Interpret source code line-by-line and executes it on the fly

• Easier to debug, allows incremental testing, and is generally faster to start execution

• Slower execution time overall and requires the interpreter to be present during the execution

Compilers

• Translates the entire source code into machine code at once and then executes it

• Faster execution time, no need for the compiler during execution

• Longer initial compilation time and can be more challenging to debug

Assemblers

• Assemblers translate assembly language into machine code

• Unlike interpreters and compilers that work with high-level languages, assemblers deal with low-level languages

• The diagram below shows examples of programming languages, from low-level to high-level

Levels of Abstraction in Programming Languages

Translators used for common languages

Why do different languages have different translators? (non-syllabus content)

• Level of Abstraction

  • High-level languages like Python or JavaScript are further from machine language and often use interpreters to allow more flexibility and ease of development

  • Low-level languages like C or Assembly are closer to machine code and typically use compilers or assemblers for efficiency

• Execution Model

  • Languages like C and C++ are compiled into machine code specific to a target platform

  • This allows for optimisations to make the code run more efficiently

  • But the code is generally not portable between different platforms

  • Languages like Python and JavaScript are interpreted, meaning they are translated line-by-line at runtime on any platform

  • This provides greater portability, as the same code can run on different platforms

  • This may sacrifice some performance compared to compiled code

• Development Paradigm

  • Interpreted languages allow determining variable types at runtime, which makes development faster

    • e.g. var x = 5 (Interpreter will calculate x to be a number at runtime)

  • Compiled languages enforce stricter type-checking at compile time, which requires additional work across the project

    • e.g. String var name = 'Michael'; (Compiler will demand that name has a data type before compiling)