Explain the benefits and drawbacks of using either a compiler or interpreter and justify the use of each

5.2 Language Translators

Objective

Explain the benefits and drawbacks of using either a compiler or an interpreter and justify the use of each.

Compilers

A compiler translates the whole source program into target code (usually machine code) before execution.

• Benefits

  • Fast execution after compilation – the generated code runs directly on the hardware.
  • Opportunity for extensive optimisation (e.g., loop unrolling, dead‑code elimination).
  • Source code is not required at run‑time, protecting intellectual property.
  • Static type checking can catch many errors before the program runs.

• Drawbacks

  • Longer development cycle – the program must be re‑compiled after each change.
  • Platform dependence: a binary compiled for one architecture usually cannot run on another without recompilation.
  • Compilation may require substantial memory and processing resources.
  • Debugging can be harder because the executed code is not the original source.

Interpreters

An interpreter reads and executes the source program line‑by‑line (or statement‑by‑statement) at run‑time.

• Benefits

  • Immediate feedback – useful for interactive development, scripting, and teaching.
  • Platform independence – the same source can run on any system that has a compatible interpreter.
  • Smaller initial distribution size; source code can be shipped directly.
  • Easy to implement dynamic features such as runtime code generation.

• Drawbacks

  • Slower execution because each statement is parsed and executed repeatedly.
  • Limited optimisation opportunities compared with a full compiler.
  • Source code must be present at run‑time, exposing it to users.
  • Runtime errors may appear later in execution, potentially reducing reliability.

Direct Comparison

When to Choose a Compiler

1. Performance‑critical applications (e.g., games, scientific computing).
2. Software that will be distributed to end‑users without exposing source code.
3. Systems with limited run‑time resources where interpreter overhead would be prohibitive.
4. Projects where extensive static analysis and optimisation are required.

When to Choose an Interpreter

1. Rapid prototyping, scripting, or educational environments where immediate feedback is valuable.
2. Cross‑platform tools that must run on many operating systems without recompilation.
3. Applications that need dynamic features such as runtime code loading or interactive command shells.
4. Small utilities where development speed outweighs execution speed.

Justification of Use

In practice, many modern languages employ a hybrid approach: source code is first compiled to an intermediate representation (e.g., byte‑code) and then interpreted or JIT‑compiled at run‑time. This combines the portability of interpretation with the speed of compilation. Examples include Java, Python (with CPython), and C#.