datagrok/noob-questions.md

## noob-questions.md

      
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    Python

__debug__ vs. -O

Python has a built-in variable __debug__ which is set to True when python is called without -O (optimize). The -O flag disables all assertion code.
This seems at first glance like a very easy and clean construct to rely on when coding in development versus production: in development, don't use -O, defensively litter your code with type- and sanity-checking asserts. Perform development-only debugging by testing __debug__ beforehand.
When in production, run all code is run with -O which disables asserts (speeding execution) and sets __debug__ to False.
Why is this construct not more popular? Why does nearly large-ish collection of python code re-invent a DEBUG global variable or the like and ignore __debug__?
Scheme

Reading http://en.wikipedia.org/wiki/Scheme_(programming_language)

Why the necessity for let, let*, and letrec? It seems like let* would do everything that let can do; and letrec can do everything let* can do. If it is a matter of performance (is let simpler and faster than letrec?) then could a clever interpreter determine which of the three was appropriate for any given set of definitions?

Smalltalk

Reading http://blog.moryton.net/2007/12/computer-revolution-hasnt-happened-yet.html

Can the "big wins" from smalltalk exist separately from some of its unusual features like

image-based persistence
a built-in graphics environment with (non-tiling) window manager, (crappy) code editor, and (interesting) code browser?
(yes, because some lisps have this image-based computing idea, and some do not?)


How does one test, package & distribute small units of smalltalk code?
Specifically about image-based persistence:

Doesn't a crash run the risk of massive loss of state? (read up about image-based persistence)
Doesn't the assumption of modifying the code on a long-running vm risk corrupting the state? How does one rollback/recover?
Examine http://stackoverflow.com/questions/722204/which-programming-languages-besides-smalltalk-are-image-based
Long-running stateful seems more vulnerable to memory leak issues and less compatible with "ephemeral" virtual hosting. False?


Specifically about SmallTalk's (Squeak's?) built-in graphical development environment:

Graphical development environment as desktop environment? As operating system?
The whizzy features of being able to interact with rotated UI elements in real-time feels slow. Can the VM take advantage of accelerated graphics libraries like OpenGL?