Interpreter
An interpreter is a language translator that translates and executes a high-level program line by line.
Notes
What is an Interpreter?
An interpreter is a language translator that translates and executes a high-level program line by line.
An interpreter reads one statement, translates it, executes it, and then moves to the next statement.
How an Interpreter Works
Example Process
- Read the first statement.
- Translate the statement.
- Execute the statement.
- Move to the next statement.
- Continue until the program ends or an error occurs.
Important Characteristics
- Translates and executes the program line by line.
- Generally does not create a separate executable file.
- If an error occurs, execution can stop at that point.
- Makes testing and debugging easier because errors can be identified during execution.
- Execution is generally slower than already compiled code.
Interpreter vs Compiler
| Feature | Compiler | Interpreter |
|---|---|---|
| Translation | Whole program | Line by line |
| Execution | After compilation | During interpretation |
| Speed | Generally faster at runtime | Generally slower |
| Error Handling | Reports errors during compilation | Can stop when an error is encountered |
| Executable File | Generally produced | Separate executable generally not produced |
Compiler = Whole Program | Interpreter = Line by Line
Examples
Interpreters are commonly associated with languages and environments such as Python, JavaScript, Ruby and PHP.
Advantages of an Interpreter
- Easy to test and debug.
- Errors can be identified during execution.
- No separate executable file is generally required.
Limitations of an Interpreter
- Generally slower execution than compiled code.
- The source program is interpreted during execution.
Quick Revision
| Point | Remember |
|---|---|
| Input | High-level source program |
| Method | Line-by-line translation and execution |
| Executable | Separate executable generally not produced |
| Error | Execution can stop when an error is encountered |
Important Exam Questions
Short Answer Questions
- What is an interpreter?
- How does an interpreter work?
- What is line-by-line translation?
- Write any three characteristics of an interpreter.
- Give examples of languages commonly associated with interpreters.
Long Answer Questions
- Define an interpreter and explain its working.
- Explain the characteristics, advantages and limitations of an interpreter.
- Differentiate between compiler and interpreter.
Watch an easy explanation of interpreter and its line-by-line execution process.
A short handwritten-style revision sheet for Interpreter is covered in the study notes above.
Use the mind map for quick revision of interpreter working and compiler comparison.