There are some edge cases that this module does not cover, and rather than recreating the wheel I would like to discuss a method to support datetime.strftime directives.

The basic strategy I am imagining would be to preprocess the given string to replace these directives with appropriate format definitions from a hard-coded table so that they are loaded into the named set. These values can then be used to set a datetime on the named set after everything is parsed.

Walkthrough example:

FMT_STR="string with {stuff}, {}, and strftime directives like %Y, %d, and %b"
parse(FMT_STR, "string with myStuff, also_this, and strftime directives like 2018, 03 and Feb").named
>> {
    "stuff": "myStuff",
    "__Y": 2018,
    "__b": "Feb",
    "__d": 3,
    "__datetime": datetime(2018, 2, 3)
}

In the above example the format string would be pre-parsed into something like :

"string with {stuff}, {}, and strftime directives like {:4d}, {:2d}, and {:3w}"

using a mapping like:

map = {
    "%Y": "{:4d}", 
    "%d": "{:2d}", 
    "%b": "{:3w}"
}
for directive, fmt in map.items():
    string = string.replace(directive, fmt)

Does this seem reasonable? I may try an implementation unless there are potential issues with this I am overlooking.