Compiler or Interpreter?

Decoding the Building Blocks of Programming

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6 min read

Compiler or Interpreter?

Ever wondered how your code comes to life? Meet the unsung heroes of programming: compilers and interpreters.


Whether you're an experienced programmer, a tech enthusiast, or just starting in the tech industry, you have likely come across the terms "compilers" and "interpreters." In this article, a technical exploration is embarked upon, diving deep into the captivating worlds of compilers and interpreters. Join me as we unravel the essence of compilers and interpreters, shedding light on their crucial roles in the realm of programming languages.

Before we dive into the technical details, let's briefly revisit the definitions of "compile" and "interpret." This will lay the foundation for our exploration of compilers and interpreters, their significance in programming languages, and the exciting journey ahead.

Compile: According to the Oxford Learner's Dictionary, compilation refers to the process of translating instructions written in one computer language into another, enabling a specific computer to understand and execute them accurately.

Interpret: In the programming world, interpretation means explaining the meaning of something.

If you have explored programming languages such as C, C++, Python, JavaScript, or others, chances are you have come across the concepts of compilers and interpreters in at least one of these languages.

What is a compiler?

Let me simplify the concept of a compiler by using an analogy that will help us grasp its technical meaning.

"Imagine that you move to a new neighborhood and make new friends. However, you realize that they don't speak the same language as you. To be able to play and communicate with them, you decide to find someone who can translate your words into a language they understand.”

Just like the person you found to translate your language to your friends, a compiler also works by translating one language into another. It takes your code written in a specific programming language and converts it into a language that the computer can understand and execute.

NB: A compiler translates all your instructions into machine code before execution.

If you are familiar with C or C++ programming languages, you may have noticed that, after compiling, you have to run an executable file with a .exe extension to see the output of your program.

How does the compiler work?

As mentioned before, a compiler functions as a translator that converts programming languages into machine code.

To accomplish this task, the compiler goes through the following procedures:

  1. The first step for the compiler is to read the instructions you have written and ensure they make sense. It's similar to how an English tutor would review your essay to check if you were adhering to specific grammatical rules. In the same way, the compiler reads your code to ensure that you are following the proper programming rules, including correct syntax and punctuation.

  2. Once the compiler has gone through your code to ensure its correctness, it proceeds to organize it in a manner that optimizes execution speed and minimizes memory usage.

  3. Once the previous steps are completed, the compiler proceeds to translate the instructions you have written into machine code that your computer can understand. This process converts high-level code into low-level instructions that the computer's hardware can directly execute.

  4. The final step in the compilation process is the execution of the generated executable file. Once you run the executable, the computer reads and executes the machine code instructions, performing the actions specified in your program

So, a compiler is like a helpful translator that takes your instructions in a language you know and turns them into a language the computer knows so that your computer can understand and do what you want it to do.

Common compilers you should know

Some of the most commonly used compilers include:

  • GCC (GNU Compiler Collection): The GCC compiler supports programming languages such as C and C++.

  • Java Compiler (javac): The Java programming language has its own compiler called "javac." It translates Java source code into Java bytecode, which can then be executed on any platform that has a Java Virtual Machine (JVM).

  • Visual C++ Compiler: This compiler is part of the Microsoft Visual Studio development environment and is used for compiling C++ programs on Windows platforms. It supports the development of Windows applications and is widely used for Windows software development.

What is an Interpreter?

In contrast to a compiler, which processes and translates all your code before execution, an interpreter reads your code line by line and executes it without generating an executable file.

An interpreter is software that converts the code you write into a format that the computer can understand. It does this by reading your code line by line, interpreting the meaning of each line, and executing the corresponding actions. Unlike a compiler, an interpreter does not generate an executable file but directly executes the code in real-time.

Here is how the interpreter works:

  1. The interpreter reads the first line of code from the program.

  2. It performs a series of tasks, including lexical analysis (breaking the line into tokens), parsing (checking the syntax), and executing the instructions.

  3. The interpreter continues this process line by line, executing each instruction as it encounters it.

Some commonly used interpreters are:

  • Python Interpreter: Python is a widely used programming language, and it has an interpreter. When you run a Python program, the interpreter reads the code line by line and executes it. The default interpreter for Python is called CPython, but there are also alternative implementations like PyPy and Jython.

  • JavaScript Interpreter: JavaScript is a scripting language primarily used for web development. Web browsers have built-in JavaScript interpreters that execute JavaScript code directly. Examples include V8 (used in Chrome and Node.js), SpiderMonkey (used in Firefox), and JavaScriptCore (used in Safari).

  • Shell Interpreters: Shell scripting languages, like Bash (Bourne Again SHell) or PowerShell, have interpreters that execute shell commands and scripts directly in a command-line environment.

NB: Compared to compiled programs, interpreted programs tend to have slower execution times because the interpretation process occurs in real-time.

Conclusion

Compilers and interpreters are both important software tools used in programming. A compiler translates the entire program into machine code before execution, while an interpreter reads and executes the program line by line without generating an executable file. Compilers are like translators that convert code into a language the computer understands, while interpreters directly interpret and execute the code. Each has its advantages and uses. Compilers are known for faster execution and efficiency, while interpreters offer flexibility and immediate feedback. Both play vital roles in the development and execution of programming languages.

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