What is Interpreter: Types, Advantages and Disadvantages

What is Interpreter: Types, Advantages and Disadvantages

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Jaya Sharma
Assistant Manager - Content
Updated on Aug 16, 2023 00:29 IST

Interpreter is a type of computer program that directly executes instructions written in a programming or scripting language.


So, what is interepreter?

An interpreter is a type of computer program that directly executes program instructions written using high-level languages.

Table of Contents

What is Interpreter?

An interpreter is a type of computer program that directly executes instructions written in a programming or scripting language. It does not require compilation into a machine learning program. Different types of interpreters are constructed for several languages that are traditionally associated with compilation. An interpreter consists of a set of commands that it can execute. 

Every command consists of the data that the programmer wants to mutate, along with the information to mutate data. Interpreters have several instructions that are specialised for performing various tasks. Most common instructions are available for memory management, mathematical operations, and branching. It directly executes instructions written in a programming or scripting language without converting them previously into an object or machine code.

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How does an interpreter work?

Interpreter transforms high level language code into machine-understandable code or an intermediate language that can be executed well. An interpreter reads every line of code, translates it into machine code and then immediately executes it. The interpreter executes every source statement line by line during execution. An interpreter provides detailed error messages and supports interactive debugging. 

Types of Interpreter

The following are different types of interpreters:

1. Threaded code interpreters 

Threaded interpreters use pointers where each instruction is a word that points towards a function or instruction sequence. These are followed by the parameters. They loop fetching instructions and then call the function that they point towards. Each instruction sequence will finish with fetching and jumping to the next instruction. 

2. Template Interpreter

This is a special type of interpreter that maintains a large arrangement of bytecode. It is directly mapped to corresponding native machine instructions. These are to be hosted on the host hardware as the key-value pairs which are known as ‘template’. When a particular code segment is executed, the template either loads or jumps to opcode mapping in the template. After this, it runs directly on the hardware. It is much faster than other types of interpreters. This is because the design of the template is simple, where it passes calls directly to the hardware rather than implementing calls. 

3. Abstract syntax tree interpreters

Such interpreters transform the source code into an optimized abstract syntax tree (AST) and execute the program following this structure. Here, each sentence is parsed at once. This allows the system to perform the analysis efficiently during the run time. Unlike bytecode interpreters, it retains a global program structure and keeps the relationship between statements intact. When it is compressed, they provide a more compact representation. 

4. Bytecode interpreter 

It is a type of interpreter that executes programs by first translating source code into intermediate and low-level representations called bytecode. This interpreter is platform-independent and comes in a compact binary format. It can be efficiently executed in comparison with original source code. Bytecode interpreter executes bytecode on a virtual machine in the runtime environment. It provides a layer of abstraction between bytecode and underlying hardware. 

5. Stack Based Interpreter

This interpreter simulates the hardware processor without general-purpose registers. The byte-code instructions must use an operand stack for holding temporary values. This interpreter uses a stack data structure for managing and executing program instructions. It reads source code line by line, thus pushing operands onto the stack and possessing them when an operation must be performed. 

6. Register Based Interpreter

This interpreter is similar to a stack-based interpreter except for the instruction set and location of parameters, return values, local variables and any temporary values. Unlike stack-based interpreters, such interpreters use virtual registers for storing operands and intermediate results. This approach results in faster execution times and better performance. 

Advantages of Interpreter

The following are the advantages of an interpreter:

  1. Interactive debugging: Interpreters allow programmers to test their code interactively, meaning they can execute code one line at a time and see the results immediately. This makes it easier to debug code and identify errors quickly.
  2. Ease of use: Interpreters typically have a simple and easy-to-use interface, making them accessible to novice programmers. Programmers can run their code without having to worry about the complexities of compilation and linking.
  3. Portability: Interpreted code can be run on any platform that has an interpreter for the programming language used. This means that the same code can be run on different operating systems and hardware configurations without the need for modification.
  4. Faster development: Interpreted languages allow programmers to write code more quickly because they can test their code immediately. This leads to faster development cycles and shorter time-to-market for software projects.
  5. More detailed error messages: Interpreters can provide more detailed error messages than compilers because they analyze and execute code one line at a time. This can help programmers identify and fix errors more quickly.

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Disadvantages of Interpreters

While interpreters offer several advantages, they also have some disadvantages, including:

  1. Slower execution speed: Interpreted code can be slower to execute than compiled code because it is translated and executed line-by-line. This can result in slower program performance and is a concern for applications that require high performance.
  2. Security risks: Interpreted languages can be more vulnerable to security risks, such as injection attacks because they allow code to be executed dynamically. This poses a security risk if the interpreter is not properly secured.
  3. Limited optimization: Interpreters are not able to optimize code to the same extent as compilers because they do not have the opportunity to analyze the entire codebase before execution. This can result in less efficient code.
  4. Limited scalability: Interpreters may have limitations when it comes to scaling, particularly when compared to compiled languages. This is because interpreted languages may require more resources to execute than compiled languages.
  5. Higher memory usage: Interpreted languages may use more memory than compiled languages because they require more resources to store the code, the interpreter, and the runtime environment.
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Jaya Sharma
Assistant Manager - Content

Jaya is a writer with an experience of over 5 years in content creation and marketing. Her writing style is versatile since she likes to write as per the requirement of the domain. She has worked on Technology, Fina... Read Full Bio