This is where I spent most of my time and honestly fumbled around more than I'd like to admit.
Start by clarifying the expected behavior of the template engine and the specific bugs, then systematically test each feature (expressions, comments, directives, escapes) with edge cases to isolate failures. Fix bugs one at a time, ensuring changes don't break other features, and validate with a comprehensive test suite.
Pro tip: Demonstrate a test-driven approach: write unit tests for each feature before fixing, and use a debugger or print statements to trace parsing steps. This shows rigor and prevents regressions.
Review the template engine's intended syntax and semantics, then create minimal test cases that reproduce each reported bug.
For each failing case, trace through the parser and interpolation logic to pinpoint the root cause, such as incorrect regex, state management, or escape handling.
Modify the code to correct the identified issues, ensuring changes are minimal and localized to avoid unintended side effects.
Run the full test suite and add new tests for edge cases (e.g., nested expressions, escaped delimiters) to confirm all features work correctly.
Clean up the code for readability, add comments explaining complex logic, and document any assumptions or limitations.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
The misnamed attribute part was actually the easiest win once I slowed down and read the node class definition carefully.
First, clarify the specific AST modification needed by examining the existing Mako AST code and its visitor pattern. Then, implement the change (add visitor method, fix attribute name, or extend visit_* method) while ensuring consistency with the AST structure and updating any related tests. Finally, verify the change by running the test suite and considering edge cases like new node types or attribute usage.
Pro tip: Demonstrate familiarity with Mako's AST by referencing its use of the visitor pattern and how nodes like `Code` and `Expression` are structured; this shows you've worked with similar template engines and can navigate unfamiliar codebases quickly.
Review Mako's AST node definitions and the visitor base class to identify how nodes are traversed and what methods exist. Locate the specific area where the change is needed (e.g., missing visitor method, misnamed attribute).
For a missing visitor method, add a `visit_<NodeType>` method that handles the node appropriately. For a misnamed attribute, correct the attribute name in the node class and update all references. For extending a `visit_*` method, add logic to handle the new node type, ensuring it integrates with existing traversal.
Add or modify unit tests to cover the new behavior, including edge cases. Update any relevant documentation or comments to reflect the change, ensuring maintainability.
Execute the test suite to confirm the change works and doesn't break existing functionality. If possible, create a small template that exercises the new feature to validate end-to-end.
Think about how the change affects other parts of the system, such as code generation or error handling. If the change is part of a larger feature, discuss potential trade-offs or alternative approaches.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.