Minilanguage

A minimal DSL for Python

Minilanguage is a minimal DSL for Python written with Ply.

Is it intended to be a starting point for writing more specific DSLs.

Currently, it only implements simple boolean logic and objects/strings evaluation.

Example

from minilanguage.grammar import Parser

context = {
    'country': 'US',
    'user': {
        'username': 'regular_user',
        'data_bag': {
            "payload": 'abc',
        }
    }
}

parser = Parser()
parser.build()

parser.evaluate("2 + 0.5", context)
# 2.5

parser.evaluate("12 + 12", context)
# 24

parser.evaluate("12 == 12", context)
# True

parser.evaluate("12 != 12", context)
# False

parser.evaluate("12 and False", context)
# False

parser.evaluate("12 or False", context)
# 12

parser.evaluate("12 > 10", context)
# True

parser.evaluate("12 < 10", context)
# False

parser.evaluate("12 <= 12", context)
# True

parser.evaluate("12 >= 12", context)
# True

parser.evaluate("country", context)
# 'US'

parser.evaluate("country == 'US'", context)
# True

parser.evaluate("user['username']", context)
# 'regular_user'

parser.evaluate("'a', 'b'", context)
# tuple('a', 'b')

parser.evaluate("user['data_bag']['payload']", context)
# 'abc'

parser.evaluate("user.get('missing_key', 'default')", context)
# 'default'

parser.evaluate("12 if False else 14", context)
# 14

License

This software is released under the MIT License.