A lightweight, optionally typed expression language with a custom grammar for matching arbitrary Python objects.
Project description
A lightweight, optionally typed expression language with a custom grammar for matching arbitrary Python objects.
Documentation is available at https://zeroSteiner.github.io/rule-engine/.
Rule Engine expressions are written in their own language, defined as strings in Python. Some features of this language includes:
Optional type hinting
Matching strings with regular expressions
Datetime datatypes
Data attributes
Example
The following example demonstrates the basic usage of defining a rule object and applying it to two dictionaries, showing that one matches while the other does not. See Getting Started for more information.
import rule_engine
# match a literal first name and applying a regex to the email
rule = rule_engine.Rule(
'first_name == "Luke" and email =~ ".*@rebels.org$"'
) # => <Rule text='first_name == "Luke" and email =~ ".*@rebels.org$"' >
rule.matches({
'first_name': 'Luke', 'last_name': 'Skywalker', 'email': 'luke@rebels.org'
}) # => True
rule.matches({
'first_name': 'Darth', 'last_name': 'Vader', 'email': 'dvader@empire.net'
}) # => FalseThe next example demonstrates the optional type system. A custom context is created that defines two symbols, one string and one float. Because symbols are defined, an exception will be raised if an unknown symbol is specified or an invalid operation is used. See Type Hinting for more information.
import rule_engine
# define the custom context with two symbols
context = rule_engine.Context(type_resolver=rule_engine.type_resolver_from_dict({
'first_name': rule_engine.DataType.STRING,
'age': rule_engine.DataType.FLOAT
}))
# receive an error when an unknown symbol is used
rule = rule_engine.Rule('last_name == "Vader"', context=context)
# => SymbolResolutionError: last_name
# receive an error when an invalid operation is used
rule = rule_engine.Rule('first_name + 1', context=context)
# => EvaluationError: data type mismatchCredits
Spencer McIntyre - zeroSteiner (@zeroSteiner)
Release history Release notifications | RSS feed
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.
Source Distribution
File details
Details for the file rule-engine-2.2.1.tar.gz.
File metadata
- Download URL: rule-engine-2.2.1.tar.gz
- Upload date:
- Size: 27.2 kB
- Tags: Source
- Uploaded using Trusted Publishing? No
- Uploaded via: twine/3.2.0 pkginfo/1.5.0.1 requests/2.24.0 setuptools/40.6.2 requests-toolbelt/0.9.1 tqdm/4.49.0 CPython/3.6.10
File hashes
| Algorithm | Hash digest | |
|---|---|---|
| SHA256 | 184875ed76430719a6ce6b47b08f3d4d32f3d9680ca42c4dcc5c25bc654b609e |
|
| MD5 | 393b1d3ec0d6a06a42016517b42f6db8 |
|
| BLAKE2b-256 | 510c4df8e0bfca500ca29871345fce43a88ff27d66f0f01f77fb7698877e6aa3 |
