pydentity is an implementation of identity functions designed for various practical applications in Python development and functional programming.

The identity function is a generic function that takes a value of any type and returns it unchanged.

from src.identity import identity

identity('hello')  # returns "hello"
identity(1)  # returns 1

This function takes a type as an argument and returns a type-specific identity function. If the type-specific function is called with a value that doesn't match the specified type, it will raise a TypeError.

from src.identity import create_identity

string_identity = create_identity(str)

string_identity('hello')  # returns "hello"
string_identity(1)  # raises TypeError: Expected value of type "str", got "int"

A wide range of built-in types are supported:

• bool
• bytes
• dict
• ellipsis
• float
• int
• list
• set
• str
• tuple
• NoneType

The identity function can be used as a no-operation placeholder during the development process, especially in the early stages when components are pending implementation.

The identity function can be employed as a default function, a fallback option for when a function is not supplied during development.

The create_identity function ensures type safety by generating type-specific identity functions in scenarios where type consistency is required.

Identity functions can be used as arguments for higher-order functions (HOFs), which accept other functions as parameters.

Identity functions, which leave their input unaltered, can be utilized in functional composition (data transformation pipelines), where a certain transformation might conditionally need to be skipped.