What do you call a computer program that directly executes instructions written in a programming language?

An interpreter is a type of computer program that directly executes instructions written in a programming language. Unlike a compiler, which translates the entire source code into machine code before execution, an interpreter translates and executes the code line by line or statement by statement. This allows for immediate execution of the code, facilitating debugging and development since programmers can see the effects of their changes in real-time.

Interpreters are commonly used for scripting languages such as Python, JavaScript, and Ruby, where rapid development and testing are essential. The ability to run code incrementally without creating a separate machine language executable file makes interpreters particularly useful in educational settings and for prototyping.

In contrast, a compiler converts the entire program into machine code, which can then be executed independently of the source code. Linkers and assemblers serve different roles in the programming and compilation process, focusing on combining object files and converting assembly language to machine code, respectively.