Can we do math in conditions?

[develop-cs]

Answer is definitely "yes" ✅

How?

By using a standard condition.

Using standard conditions is the most versatile way of using Arta.

Example

rules.yaml:

---
rules:
  default_rule_set:
    example_rule:
      OK:
        condition: A_BY_B_GT_THRESHOLD
        action: do_something
        action_parameters:
          value: OK
      KO:
        condition: not A_BY_B_GT_THRESHOLD
        action: do_something
        action_parameters:
          value: KO

conditions:
  A_BY_B_GT_THRESHOLD:
    description: "A*B > threshold?"
    validation_function: is_mul_greater_than
    condition_parameters:
      a: input.value_a
      b: input.value_b
      threshold: 0.87

conditions_source_modules:
  - conditions
actions_source_modules:
  - actions

conditions.py:

def is_mul_greater_than(a: float, b: float, threshold: float) -> bool:
    return a * b > threshold

actions.py:

def do_something(value: str, **kwargs) -> str:
    return value

main.py:

from typing import Any

from arta import RulesEngine

eng = RulesEngine(config_path=".")

data: dict[str, float] = {
    "value_a": 1.3,
    "value_b": 0.7,
}

result: dict[str, Any] = eng.apply_rules(input_data=data)

print(result)

It should print:
{'example_rule': 'OK'}

1.3*0.7=0.91, greater than 0.87.

Warning: For now you can't use a simple condition for math but we will work on that. See next comment.

Enhancement: The following enhancement proposal could be useful with math in conditions: #7

[develop-cs]

Since final release 0.7.0, math expressions are implemented for simple conditions (only basic operators like: +, -, * and /).

Example:

---
rules:
  default_rule_set:
    math:
      OPS:
        simple_condition: input.x+input.y>input.threshold and input.x*input.y<123.4
        action: do_nothing
        action_parameters: null