Pippy Design Idea 2011-03-10
A learner will:
- review and run an included example module, observing code and behaviour,
- modify an included example module, and run the modified version, observing changed behaviour,
- write a fresh module, creating new behaviour,
- write a fresh module that imports an included example module unchanged, deriving behaviour from existing behaviour,
- write a fresh module that imports a modified example module,
- write two fresh modules one of which imports the other,
- derive more complex code using modules created by teachers or other learners, with or without changing the contributed module.
A group of learners will do the above, but also:
- collaborate on a set of modules included in the shared activity instance,
- run modules locally on each laptop.
A pair of learners may:
- create one subordinate module each, and concentrate on it,
- create one master module that imports the two subordinate modules,
- write unit tests in each subordinate module and run them locally on each laptop,
- integrate by running the master module.
- increase code sharing, at a module level,
- increase relevance to Python users,
- increase portability of code written, beyond Pippy and Sugar,
A running Pippy instance will contain the following data:
- zero or more modules,
- (either pure python modules, packages, or distutil source distributions, though not a sugar bundle),
- each module will include zero, one (pure python modules) or more (packages or distutil source distributions) source files,
- each module will include a source file setup.py capable of creating the python distutil source distribution output, but unless the user has asked to edit the setup.py, it will not be shown, instead a default will be used, created and maintained by Pippy,
A shared Pippy will contain the same data as above on each laptop.
Pippy may read from:
- a saved instance of Pippy, in the journal, by activation only,
- a module in the journal, (which may have come from a teacher, another learner, or a server), using the object chooser,
- in pure python module form, as a single source file,
- in distutil source distribution form, as multiple source files inside a tar or zip container,
- pristine example modules included with Pippy, using a button and an example chooser.
Pippy may write to:
- a saved instance of Pippy, in the journal,
- a pure python module, in the journal,
- represented as a single source file,
- a package module, in the journal,
- represented as a distutils source distribution in tar or zip container.
Pippy may be activated from a journal entry:
- a saved instance of Pippy, which will start the Pippy activity and present the modules and files that were visible at the time the saved instance was created, allowing the learner to resume development,
- a pure python module or package module, which will start the Pippy activity in an execution only mode that behaves in the same way as the "run" button, displaying a VTE (only if stdout is written to, or stdin is read from), and if not exiting immediately, without creating a journal entry.
Display will contain:
- a series of tabs, one for each module, an add module button, and an open example module button,
- within each module, a series of tabs, one for __doc__ that is not editable (only if the module has non-empty __doc__), one for each source file that is editable, and an add file button,
- within each file, a syntax highlighting text edit widget.
(the series of tabs encapsulated in another series of tabs is potentially difficult for a learner to comprehend, but an alternative tree view is thought inappropriate because of the horizontal space consumed, and because use of a module should be constrained to the public API of the module).
When run is pressed, display will contain:
- stdout stdin vte, (only if stdout is written to, or stdin is read from),
- a stop button.
Partial list of changes to bring Pippy existing source to a state consistent with the design above:
- remove the examples widget from the main screen, provide it only as an "open an example bundle" function,
- remove the output window from the main screen, provide it only when a program is run, and only if the program generates stdout or reads from stdin,
- enlarge the program text entry widget to be nearly full screen,
- encapsulate the program text entry widget in tabs for files in a zip bundle,
- encapsulate the bundle in tabs for zip bundles loaded into pippy instance,
- on standard sugar save, save all zip bundles and files in a sugar journal entry,
- provide an export zip bundle button that creates a sugar journal entry of type zip bundle, for sharing,
- provide a way to import zip bundles from journal into the current pippy instance, using the object chooser,
- on execution of a bundle, allow access to all other currently loaded bundles via import, and access to system bundles via import,
- create a new activity.
Pippy currently provides example scripts written in Python, allows the learner to run them, edit them, and save them as a journal entry. Pippy does not currently support creation of modules, or use of modules other than operating system- or Pippy-packaged modules.
- Script ... "Therefore, if you want to write a somewhat longer program, you are better off using a text editor to prepare the input for the interpreter and running it with that file as input instead. This is known as creating a script."
- Module ... "the basic unit of code reusability in Python: a block of code imported by some other code. Three types of modules concern us here: pure Python modules, ..., and packages."
- pure Python module ... "a module written in Python and contained in a single .py file ... Sometimes referred to as a “pure module.”"
- package ... "a module that contains other modules; typically contained in a directory in the filesystem and distinguished from other directories by the presence of a file __init__.py."