wcfg 1

Parser for hyerarchical text data and configuration files

wcfg is a small module to parse hierarchical data from text files, and it is particularly suitable for configuration files.

Features:

• Text-based, hierarchical format, with simple syntax which is designed to be easy to parse both by programs and humans.

• Both reading and writing back is supported. Written data is guaranteed to be readable back to its original representation.

• Small, self-contained, pure Python implementation.

Grammar

This is the grammar accepted by the parser, in [EBNF syntax](https://en.wikipedia.org/wiki/Extended_Backus%E2%80%93Naur_Form):

identifier = - ( whitespace | “:” )

string character = - “"”

key-value pair = identifier, “:”, value

identifier, value

octal digit = “0” | “1” | “2” | “3” | “4” | “5” | “6” | “7”

digit = octal digit | “8” | “9”

hexdigit = digit | “a” | “b” | “c” | “d” | “e” | “f”

“A” | “B” | “C” | “D” | “E” | “F”

sign = “-” | “+”

integral number = digit, { digit }

dotted float = “.”, digit, { digit }

digit, “.”, { digit }

exponent = (“e” | “E”), sign, digit, { digit }

(“e” | “E”), digit, { digit }

float number = dotted float

dotted float, exponent

integral number, exponent

number body = integral number

float number

number = “0”, ( “x” | “X” ), hex digit, { hex digit }

“0”, octal digit, { octal digit }

sign, number body

number body

value = “"”, { string character }, “"”

“[”, { value } “]”

“{”, { key-value pair }, “}”

number

input = “{”, { key-value pair }, “}”

{ key-value pair }

Note that comments are not specified in the grammar above does not include comments for the sake of simplicity. Comments can appear anywhere except inside strings, and they span from the octothorpe sign (#) to the end of the line.