Tuple DSL documentation

DSL

DSL let us create any operation over a row, but you know… with great power comes great responsibility.

When you create an operation, you have to spread the input, the modified output and the error if proceeds.

Its usage is very simple. For example, keep function is shown below:

def keep(fields) -> Callable[[dict, dict, dict], Tuple[dict, dict, dict]]:
    operations = [compose(use_input(), read_field(f), write_field(f)) for f in fields]
    return reduce(compose, map(apply_over_output, operations))

In this example you can see a composition that takes different functions for every field. keep returns an unique function that contains all of them applied on output.

List of functions

• read_field
• read_match
• read_fields
• write_field
• write_error_field
• dict_enforcer
• apply_over_output
• compose
• fixed_input

You can create your own function too. It has to return a function that takes 2 dictionaries (input and error) and returns them modified if it’s necessary as (output, error).