gcl

gcl -- Generic Configuration Language

GCL is an declarative modeling language that can be dropped into any Python project. It supports dictionaries with name-value pairs, all the basic types you'd expect, lists, includes, and methods for abstraction.

The goal for GCL is to be a modeling language with lots of expressive power, intended to make complex configurations extremely DRY. Behavior is not part of the goal of the language; behavior and semantics are added by scripts that interpret the GCL model.

Documentation

Detailed documentation is available at http://gcl.readthedocs.org

Quick GCL showcase

GCL is built around named tuples, written with curly braces:

# This is a comment
# Various data types:
number = 1;
string =  'value';  # Strings can be doubly-quoted as well
bool =  true;       # Note: lowercase
expression = number * 2; 
list = [ 1, 2, 3 ];

Expressions:

a = 1 + 1;
b = 'foo' + 'bar';
c = 80 * '-';

d = inc(1);  # Function application
e = inc 1;   # Can omit parens with 1 argument

# Conditionals
allow_test_commands = if stage == 'alpha' then true else false;

# List comprehension
evens = [ x * 2 for x in [1, 2, 3, 4, 5] if x % 2 == 0 ];

Tuples and accessing tuple members:

tuple = {
  foo = 3;
}

that_foo = tuple.foo;

Includes and tuple composition:

http = include 'library/http.gcl';
server = http.Server {
    port = 8080;
}

Using the library

You now know enough GCL to get started. Using the library looks like this:

import gcl
from gcl import util

# Load and evaluate the given file
model = gcl.load('myfile.gcl')

# This gives you a dict-like object back, that you can just index
print(model['element'])

# Translate the whole thing to a Python dict (for example to convert to JSON)
dict_model = util.to_python(model)

import json
print(json.dumps(dict_model))

Requirements

• Uses pyparsing.

Extra

• Vim syntax definitions available: https://github.com/rix0rrr/vim-gcl