No, interpret a constrained grammar. Restrict the operations the rule is permitted to express.

Interpreter gives each grammar production an evaluation operation. Flag and And form a minimal boolean expression language; missing values are false by contract. User-facing systems need a parser that only builds allowed node types, validation, depth limits, and controlled context access. Trusted object construction here deliberately avoids parsing and arbitrary execution.

What the function promises: Expressions use trusted Flag and And nodes over a dictionary. A flag is enabled only when its value is exactly True.

class Flag:
    def __init__(self, name):
        self.name = name
    def evaluate(self, context):
        return context.get(self.name) is True

class And:
    def __init__(self, left, right):
        self.left, self.right = left, right
    def evaluate(self, context):
        return self.left.evaluate(context) and self.right.evaluate(context)

rule = And(Flag("member"), Flag("active"))
assert rule.evaluate({"member": True, "active": True})
assert not rule.evaluate({"member": True})
assert not rule.evaluate({"member": "yes", "active": True})

Work and storage: O(visited expression nodes), with short-circuiting and recursion proportional to depth.

When to recognize it: A larger language needs parsing, validation, and work limits. User text should not become unrestricted Python execution.

Check before applying it: Constrained languages still need limits on grammar, depth, work, and context access.

No. Detect cycles or define a deliberate fixed-point interpretation. A finite-tree evaluator has no automatic semantics for recursive rules.