tree d15fcbe5f806449924e0ccb1c9953fec8ee9287f
parent b05c53fb01342873787b545359f443b5dbf2be7f
author Sketch🕴️ <skallywag@sketch.dev> 1772291686 +0400
committer Sketch🕴️ <skallywag@sketch.dev> 1772291686 +0400

Step 6: Implement evaluator with TDD

- Eval(ast.Node) (float64, error) - recursive AST walker
- Handles all 4 operators: +, -, *, /
- Division by zero returns error
- Error propagation from sub-expressions
- 10 unit tests covering: single number, all operators, nested/deep
  expressions, division by zero (direct and in sub-expr), floats