Python Tutor currently does NOT support the following language features. Some of these features will eventually be supported, but others probably won't, due to implementation challenges and other priorities.
Email [email protected] with more bug reports and use the "Generate shortened link" button to include a URL so that I can reproduce them.
For more details on project status and issue prioritization, check out these videos from March 2018:
- Python Tutor project status - 1 of 2 - common feature requests & feasible fixes
- Python Tutor project status - 2 of 2 - bigger feature requests & unlikely fixes
... and this earlier video from Oct 2017: Python Tutor Software Development Philosophy
- unions
- some complex typedefs
- taking text input from the user using scanf(), cin >>, etc.
- code with memory-related errors: it will fail-fast using Valgrind Memcheck
- doesn't show when function parameters get mutated
- function return values are not visualized
- stack arrays without compile-time sizes
- read-only memory isn't visualized separately from the heap
- asynchronous event-driven code
- including setTimeout, setInterval, etc.
- promises, async/await
- anything that operates on webpages, such as DOM manipulation, alert(), prompt(), confirm(), etc.
- Date() object
- some infinite loops: the server times out without showing partial results or good error messages
- to cut down execution times, set Python breakpoints using
#breakcomments
- to cut down execution times, set Python breakpoints using
- asynchronous code
- random number generators and user input (via input() or raw_input()) sometimes don't work well together
- no 3rd-party library/module support: use the experimental "Python 3.6 with Anaconda" mode if you want to import many more modules from the Anaconda distribution
- (note: remember that Python 2 and 3 support slightly different kinds of language constructs)
- Stepping within a line of code to show how subexpressions get evaluated within that line
- Unicode doesn't work well in general (especially for Ruby and Python 2); use ASCII characters when possible
- Passing in command-line arguments via argv[] array
- Multi-threaded, concurrent, or asynchronous code
- Anything involving GUI programming or GUI/webpage components
- Reading data from external files; put all your data in strings when possible
- Interfacing with databases, network, filesystem, or other external resources
- Importing external 3rd-party libraries (try "Python 3.6 with Anaconda (experimental)" if you want to use more libraries)
- Code that is too large in size; shorten your code!
- Code that runs for too many steps (e.g., > 1,000 steps) or for a long time
- shorten your code to isolate where you want to visualize and debug
- or set Python breakpoints using
#breakcomments
- If you're behind some kinds of firewalls or proxy servers, the visualizer may not work
Look through these issue trackers for additional bugs and unsupported features: