fpin

fpin refers to a functional programming idiom for pushing a value into a nested data structure, typically a list or a nested list. The term is derived from the concept of "function piping" or "function composition" commonly found in functional programming languages. Instead of modifying the structure in place or creating multiple intermediate copies, fpin allows for a concise and declarative way to add an element to a deeply nested collection.

The core idea behind fpin is to avoid mutable state and side effects. When working with immutable data structures, modifying a nested element often requires reconstructing the entire path from the root to the element being changed. Fpin provides a syntax or a set of combinators that abstract this process. This can make code more readable and less prone to errors, especially when dealing with complex, nested data.

Different functional programming languages or libraries might implement fpin with slightly different syntax or through specific higher-order functions. However, the underlying principle remains the same: to efficiently and immutably update nested data structures by adding a new element at a specified location. This can be particularly useful in scenarios where data is frequently transformed or updated, such as in state management within user interfaces or data processing pipelines.