Add lists converter

Current State

There are already a few ways how cs helps to convert untyped values to typed ones. For example when loading ini-files or environment variables there are no typing information. For that a user can specify converters, so that he gets already typed values when he access a key.

At the moment configstacker supports

• bools
• dates
• datetimes

Now when a key in such a source has multiple values, one has to specify a custom converter to deal with lists.

import configstacker as cs

# assuming an untyped source
source_data = {'a': '1,2,3'}

# custom converters
def to_list(value):
    tokens = value.split(',')
    return [int(t) for t in token]

def to_str(value):
    return ','.join([str(v) for v in value])

cfg = cs.DictSource(
    source_data,
    converters=[('a', to_list, to_str)]
)

assert cfg.a == [1, 2, 3]

Proposal

As list conversion is quite predictable it would be nice to also provide a built-in list converter. That way one can focus on converting the individual elements of the list.

import configstacker as cs

# assuming an untyped source
source_data = {'a': '1,2,3'}

cfg = cs.DictSource(
    source_data,
    converters=[cs.converters.lists('a', int, str)]
)

assert cfg.a == [1, 2, 3]