pure_eval_ast_node_safe_expression_evaluation.py

1import ast
2from pure_eval import Evaluator
3
4source = "x + 1"
5tree = ast.parse(source)
6node = tree.body[0].value
7
8# The evaluator needs to know the values of names in the expression
9names = {"x": 10}
10
11# Create the evaluator
12evaluator = Evaluator(names)
13
14try:
15    # Attempt to evaluate the node
16    result = evaluator[node]
17    print(f"The value of '{source}' is {result}")
18except KeyError:
19    print(f"Could not evaluate '{source}' (it may not be pure or names are missing)")