string-kit 0.1.0a7

Library of string functions and formatters

Description

Provides advanced string utilities and a powerful Formatter.

This is a development version, and while it has been thoroughly tested, it will be battle-tested in a live project and updated as needed.

Formatter

string_kit.Formatter is a drop-in replacement of string.Formatter and supports the same syntax and more.

string_kit.Formatter adds the following features:

• virtual fields now, uuid1, uuid4, uuid5 (no key is required in the format parameters, however if present, they take precedence); many more coming up.

• user-defined virtual fields can be added through field_default init parm.

• can send namespaces where format field values are searched through namespaces init parm.

• !capitalize, !lower, !lstrip, !rstrip, !slug, !strip, !title, !upper; many more coming up.

• user-defined convertors can be added through convertors init parm.

• chained conversions and format specifications in any order: {field!slug:.10s!upper}.

• user-configurable silence_missing_fields, if set True, will suppress IndexError and KeyError and will quietly replace with empty string.

• user-configurable characters to identify fields (default {}), convertors (default !) and format specifiers (default :).

A simple example:

import random
from string_kit import Formatter

the_weather = "Sunny but Humid"

custom_field_defaults = {
    "password": lambda: random.choice(["lI0n", "rAbb1t", "tig3R"]) \
                        + str(random.randint(1000, 9999)),
}

custom_convertors = {
    "greeting": lambda str_, greeting: f"{greeting} {str_}",
}


class CustomFormatter(Formatter):
    field_defaults = {
        "bye": "Good bye!",
    }
    convertors = {
        "space2dash": lambda str_: str_.replace(" ", "-")
    }


skf = CustomFormatter(
    silence_missing_fields=True,
    field_defaults=custom_field_defaults,  # optional, dict with str or callable values
    convertors=custom_convertors,          # optional, dict with callable values
    field_namespaces=[locals()],           # optional, namespaces to search for field names
)

print(skf.format("{name!space2dash!greeting(Hello)},"
                 " your random password is: '{password}'. {bye}",
                 name="Charlie Brown"))
# "Hello Charlie-Brown, your random password is: 'rAbb1t1258'. Good bye!"

print(skf.format("Today is {now!strftime(%A)!upper}, also a"
                 " {the_weather!lower:.5!replace(sunny,sunny \\(☀️\\))} day."
                 " {missing!lstrip}"))
# "Today is FRIDAY, also a sunny (☀️) day. "

Some TODO Ideas

• add snake_case, kebab-case, PascalCase, camelCase as built-in convertors

• add sqids convertor with parameters (strings allowed, length) passed as static values