perky

Because the world needed another configuration file format

Copyright 2018 by Larry Hastings

Overview

Perky is a new, simple rcfile format for Python programs.

The following are Perky features:

Perky syntax

Perky configuration files look something like JSON without the quoting.

example name = value
example dict = {
    name = 3
    another name = 5.0
    }
example list = [
    a
    b
    c
    ]
# lines starting with hash are ignored

# blank lines are ignored

" quoted name " = " quoted value "

triple quoted string = """

    indenting
        is preserved

    the string is automatically outdented
    to the leftmost character of the ending
    triple-quote

    <-- aka here
    """

Explicit transformation is better than implicit

One possibly-surprising design choice of Perky: the only natively supported values for the Perky parser are dicts, lists, and strings. Other commonly-used types (ints, floats, etc) are handled using a different mechanism: transformation.

A Perky transformation takes a dict as input, and transforms the contents of the dict based on a schema. A Perky schema is a dict with the same general shape as the dict produced by the Perky parse, but it contains dicts, lists, and transformation functions. If you want myvalue in {'myvalue':'3'} to be a real integer, transform it with the schema {'myvalue': int}.

API

perky.loads(s) -> d

Parses a string containing Perky-file-format settings. Returns a dict.

perky.load(filename, encoding="utf-8") -> d

Parses a file containing Perky-file-format settings. Returns a dict.

perky.dumps(d) -> s

Converts a dictionary to a Perky-file-format string. Keys in the dictionary must all be strings. Values that are not dicts, lists, or strings will be converted to strings using str. Returns a string.

perky.dump(filename, d, encoding="utf-8")

Converts a dictionary to a Perky-file-format string using perky.dump, then writes it to filename.

perky.transform(d, schema) -> o

Recursively transforms a Perky dict into some other object (usually a dict) using the provided schema.

perky.Required

perky.nullable(fn) -> fn

perky.const(fn) -> o

TODO

• Backslash quoting currently does "whatever your version of Python does". Perhaps this should be explicit, and parsed by Perky itself?