Homoiconicity (/ˌhɒməʊaɪkəˈnɪsɪti/) is a term used in computer science to describe a property of some programming languages where code and data structures have the same syntax. The word is spelled with four syllables, each pronounced distinctly. The "homo" in the beginning is pronounced as "ho-moe", similar to the word "homogeneous". The "icon" in the middle is pronounced as "eye-kon", like the word "iconic". The "icity" at the end is pronounced as "i-si-tee", like the word "electricity".
Homoiconicity is a technical term used in the field of computer science, particularly in programming languages and systems. It refers to the property of a programming language or system where the program structure itself can be represented using the same syntax as the data.
In a homoiconic programming language or system, the code and data are treated similarly, and the program can manipulate itself or other parts of the program as if they were simple data structures. This means that programs can dynamically create, modify, and execute code as they run, enabling powerful metaprogramming capabilities.
The concept of homoiconicity is closely related to the idea of reflection, but it focuses specifically on the representation of code as data. Homoiconic programming languages provide features like code generation, code introspection, and the ability to modify and extend the language itself during runtime. These languages often have a simple, uniform syntax that makes it easier to represent code as data.
One of the most well-known examples of a homoiconic language is Lisp. In Lisp, programs are represented as lists, and the language's syntax and data structure are essentially the same. Lisp's homoiconicity allows for powerful macros, where the programmer can write code that generates and modifies other code.
Overall, homoiconicity is a fundamental property of certain programming languages and systems that enables code to be treated as data, leading to greater flexibility, programmability, and metaprogramming capabilities.
The word "homoiconicity" is derived from two Latin roots: "homo-" and "-iconic".
1. "Homo" means "same" or "similar" in Latin.
2. "-Iconic" comes from the Greek word "eikōn", meaning "image" or "representation".
When combined, "homoiconic" implies something that has the same or similar form or representation. In the specific context of computer programming, the term refers to a language feature where code can be manipulated as data, enabling programs to generate and interpret code expressions as regular data structures. This concept was first introduced in the programming language Lisp, where programs are written in a syntax that closely resembles its data structure representations, giving rise to the term "homoiconicity".