Pformatlike

Pformatlike is a feature of the Python language that allows developers to format a formatted value. This feature is particularly useful when working with formatted values, such as those produced by the built-in str.format() method or string literals.

Pformatlike is primarily used to preserve the formatted state of a value, ensuring that any subsequent calls to the format() method will apply to the same formatted value rather than its string representation. This feature is most commonly employed when working with containers like lists or dictionaries that contain formatted values.

The approach of using pformatlike was introduced in Python 3.7 as part of PEP 510. Its implementation allows developers to define a custom formatter class, implement the f() method to format values, and then use pformatlike to apply the formatted values to PEP 510's format() function.

One of the key benefits of pformatlike is the ability to customize the formatting process without affecting the overall structure of the formatted value. For instance, if a value contains a representation of a list, the formatter can be used to preserve that list's formatting.

In summary, the pformatlike feature provides a flexible solution for developers to work with formatted values, enabling customization and preservation of the formatted state. While it may not be a widely used feature, its potential impact on projects that rely on formatted values cannot be understated.