Rule Engine

Getting started

Rust

If you do not have it installed already you must install Cargo. Check the Rust Documentation for instructions on how to do this

Build the project

cargo build

Optimized build

cargo build --release

Python

Install the dependencies

pipenv sync --dev

Update from source

pipenv run refresh

Run the tests

pipenv run test

Performance Analysis

Profile Rust

We can use Instruments to profile the Rust code to help us find bottlenecks. To do this we need to build the project with debug symbols.

cargo build --release

Then we can use the cargo-instruments tool to profile the binary. You can install it with cargo like this:

cargo install cargo-instruments

Finally, we can run the profile. This will open Instruments and start recording.

cargo instruments -t "CPU Profiler" --bin profiler --release

Rule Engine Comparisons

Currently, we have comparisons for the following rule engine implementations:

Rust rule-engine
Python rule-engine
GoRules zen
Python eval

You can run the script to compare the performance of these implementations. You can also modify the rules each engine will evaluate by modifying the compare.py script.

pipenv run compare

Grammar

This is the grammar for the rule engine. It does not reflect the current state of the implementation, but it can help new engineers understand the language. This grammar is not complete and will be updated as the language evolves.

expression = logical_expression;

logical_expression = equality_expression { ("and" | "or") equality_expression };

equality_expression = comparison_expression { ("!=" | "==") comparison_expression };

comparison_expression = additive_expression { (">" | ">=" | "<" | "<=" ) additive_expression };

additive_expression = factor_expression { ("+" | "-" ) factor_expression };

factor_expression = unary_expression { ("/" | "*" | "%" ) unary_expression };

unary_expression = ( "not" | "-" ) unary_expression | primary_expression;

primary_expression = IDENTIFIER | STRING | INTEGER | "true" | "false" | "null"| 
                     list_literal | "(", expression, ")"

list_literal = '[', expression,  { ',', expression } ']'; 

function_call = IDENTIFIER, '(', argument_list , ')'

argument_list = [ expression , { ',' , expression } ]

HankBreck/rules-engine