Re: Is it possible to create C-style main function in Python? (for teaching purposes)
I do not think C is not good for functional programming, but C is hard to debug if one has to write programs to reload functional pointers and data structures that will grow in the run time for the possible cases. Thus, I love Python! -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
Dennis Lee Bieber wlfr...@ix.netcom.com wrote: While I wouldn't want to write an FFT in COBOL, one can't deny that laying out fixed width reports and moving blocks of decimal data between record layouts is quite easy in COBOL. Absolutely. I've always thought the Data Section in COBOL was conceptually ahead of its time. It makes you THINK about your data structures more than, say struct in C. -- Tim Roberts, t...@probo.com Providenza Boekelheide, Inc. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
Dennis Lee Bieber wlfr...@ix.netcom.com wrote: While I wouldn't want to write an FFT in COBOL, one can't deny that laying out fixed width reports and moving blocks of decimal data between record layouts is quite easy in COBOL. Well, sure, but there's still plenty of pain in the verbosity :) -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
alex23 wrote: But on the gripping hand, it is a clear triumph of Explicit is better than implicit. ;) I think we may have found the long-lost 20th principle of the Zen: If it results in eye-bleedingly horrible code, it might be a bad idea. -- Greg -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On Wed, Oct 5, 2011 at 12:22 PM, Alan Meyer amey...@yahoo.com wrote: Of course you'll need to be fair in evaluating the students comparisons. Some bright students are likely to come up with good reasons for using globals in some situations, and they might even be right. Or if they're not completely right, they might nevertheless be partly right. They should get high marks for that. Definitely. There's always a right time to do the wrong thing, just as much as there's a wrong time to do the right thing. Even the much-maligned goto has its place. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
Steven D'Aprano steve+comp.lang.pyt...@pearwood.info writes: import the module called 'math' into the current namespace and bind that module to the name 'math' in the current namespace bind the name 'x' in the current namespace to the return result of calling the attribute named 'sin' in the object currently bound to the name 'math' in the current namespace using the float literal 1.2345 as the argument This mocking is hurtful to people who identify too strongly with COBOL. I wonder whether that means it's intentionally hurtful. -- \ “The long-term solution to mountains of waste is not more | `\ landfill sites but fewer shopping centres.” —Clive Hamilton, | _o__)_Affluenza_, 2005 | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
In article mailman.1737.1317798109.27778.python-l...@python.org, Chris Angelico ros...@gmail.com wrote: Definitely. There's always a right time to do the wrong thing, just as much as there's a wrong time to do the right thing. Even the much-maligned goto has its place. Not in python, it doesn't :-) But, yes, I agree that in languages that support it, it can be useful. When I was writing C++ for a living, I must have written a goto at least once every couple of years. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On Wed, Oct 5, 2011 at 11:57 PM, Roy Smith r...@panix.com wrote: In article mailman.1737.1317798109.27778.python-l...@python.org, Chris Angelico ros...@gmail.com wrote: Definitely. There's always a right time to do the wrong thing, just as much as there's a wrong time to do the right thing. Even the much-maligned goto has its place. Not in python, it doesn't :-) The absence from the language doesn't prove that. All it means is that, on those rare occasions when a goto would have been correct, the programmer had to make do with something else :-) How often do you see a loop structure that exists solely so someone can 'break' out of it? Or, worse, raising an exception? I haven't seen it in Python, but frequently in C or C++ code where the programmer had a fixation on avoiding gotos. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On Tue, Oct 04, 2011 at 08:20:34PM -0700, alex23 wrote: Steven D'Aprano steve+comp.lang.pyt...@pearwood.info wrote: Imported modules are variables like any other, and as they usually exist in the global scope, so they will all need to be explicitly referenced as global. This will get tiresome very quickly, and is a cure far worse than the disease, and alone is enough to disqualify this suggestion from serious consideration. But on the gripping hand, it is a clear triumph of Explicit is better than implicit. ;) Simple is better than complex. Readability counts. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
Ben Finney ben+pyt...@benfinney.id.au wrote: This mocking is hurtful to people who identify too strongly with COBOL. I wonder whether that means it's intentionally hurtful. Far, _far_ less hurtful than COBOL itself... -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On Oct 5, 11:10 pm, Chris Angelico ros...@gmail.com wrote: The absence from the language doesn't prove that. All it means is that, on those rare occasions when a goto would have been correct, the programmer had to make do with something else :-) Like the goto module? :) http://entrian.com/goto/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On 03Oct2011 13:10, rantingrick rantingr...@gmail.com wrote: | Also for scoping. | | py count = 0 | py def foo(): | ... global.count += 1 | py print count | 1 | | Why? Well because many times i find myself wondering if this or that | variable is local or global -- and when i say global i am speaking | of module scope! The globalDOT cures the ill. I must admit I rarely have this concern. My own module globals are almost entirely CONSTANT type names. (Excluding function and class names.) What's the common ambifuity case for you? -- Cameron Simpson c...@zip.com.au DoD#743 http://www.cskk.ezoshosting.com/cs/ Generally, these things are dreadful, but I saw a clip the other night on tv of someone who had built a scorpion costume for their spaniel, complete with legs and a stinger. It was quite impressive. Made me want to run out and buy a dog and a some foam rubber. - David Farley -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On Thu, Oct 06, 2011 at 02:44:33PM +1100, Cameron Simpson wrote: On 03Oct2011 13:10, rantingrick rantingr...@gmail.com wrote: | Also for scoping. | | py count = 0 | py def foo(): | ... global.count += 1 | py print count | 1 | | Why? Well because many times i find myself wondering if this or that | variable is local or global -- and when i say global i am speaking | of module scope! The globalDOT cures the ill. I must admit I rarely have this concern. My own module globals are almost entirely CONSTANT type names. (Excluding function and class names.) What's the common ambifuity case for you? I never have this concern either. Python's functions and classes are powerful enough to avoid globals entirely. In C I have a few sometimes and in Fortran and the like they're everywhere. Global variables are POWERFUL and USEFUL but there's a certain paradigm that goes with them, and Python works better with an object-oriented w/ functional elements approach. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On Thu, Oct 6, 2011 at 2:36 PM, alex23 wuwe...@gmail.com wrote: On Oct 5, 11:10 pm, Chris Angelico ros...@gmail.com wrote: The absence from the language doesn't prove that. All it means is that, on those rare occasions when a goto would have been correct, the programmer had to make do with something else :-) Like the goto module? :) http://entrian.com/goto/ Yes. That module is extremely valuable and needs to be brought into the main trunk. Rick, can this go on your Python 4000 list? ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
REMEMBER STEVE On Wed, Oct 5, 2011 at 9:58 PM, Chris Angelico ros...@gmail.com wrote: On Thu, Oct 6, 2011 at 2:36 PM, alex23 wuwe...@gmail.com wrote: On Oct 5, 11:10 pm, Chris Angelico ros...@gmail.com wrote: The absence from the language doesn't prove that. All it means is that, on those rare occasions when a goto would have been correct, the programmer had to make do with something else :-) Like the goto module? :) http://entrian.com/goto/ Yes. That module is extremely valuable and needs to be brought into the main trunk. Rick, can this go on your Python 4000 list? ChrisA -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
Thanks for all the comments! It seems that the best way is still just to teach students self discipline. And hope that they (for now) believe some things (eg. dangers of global variables) without seeing. Aivar -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On Mon, Oct 03, 2011 at 09:35:16PM -0700, alex23 wrote: Sorry for hijacking Alec's response but I didn't see the OP. Aivar Annamaa aivar.anna...@gmail.com wrote: I'm looking for a trick or hidden feature to make Python 3 automatically call a main function but without programmers writing `if __name__ == __main__: ...` One direct way is to call it from the command line: python -c import mymodule; mymodule.main() After your students have had to use that verbose form for a while, they'll be more than happy to add the boilerplate themselves to the end of their modules :) Boiler plate is silly. Let the students figure out stuff themselves. The students need to know why global variables in functions is unwieldly, not just not use them because it's cool. When I taught myself Python I quickly realized global variables were unwieldly and usually impractical after using them. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
Westley Martínez aniko...@gmail.com writes: Boiler plate is silly. Let the students figure out stuff themselves. That argues directly against the Primacy effect mentioned earlier URL:https://secure.wikimedia.org/wikipedia/en/wiki/Principles_of_learning#Primacy URL:https://secure.wikimedia.org/wikipedia/en/wiki/Serial_position_effect, which is demonstrated by much scientific evidence. What scientific evidence do you have to argue against it? The students need to know why global variables in functions is unwieldly, not just not use them because it's cool. If you say so. But why not show them the traps after *first* teaching them the recommended way to do it? When I taught myself Python I quickly realized global variables were unwieldly and usually impractical after using them. That's no argument at all against how to teach Python in a teacher-student relationship. -- \“If you have the facts on your side, pound the facts. If you | `\ have the law on your side, pound the law. If you have neither | _o__) on your side, pound the table.” —anonymous | Ben Finney -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On 10/3/2011 12:26 PM, Alec Taylor wrote: ... On Tue, Oct 4, 2011 at 3:21 AM, Aivar Annamaaaivar.anna...@gmail.com wrote: ... I'm looking for a trick or hidden feature to make Python 3 automatically call a main function but without programmers writing `if __name__ == __main__: ...` ... Here's why I want such a thing: I'm teaching introductory programming course with Python. I've seen that global variables attract beginners like honey attracts bees and this makes teaching function parameters harder. ... Teaching good programming practice is hard. Many programmers, not just students, take the attitude, My code works. Who cares what it looks like? Getting them to understand that code has to be readable, understandable, and maintainable can be very hard. I wonder if some teaching exercises would help, for example: 1. Find a program, perhaps submitted by a student in a previous class or perhaps something you write yourself, that's full of global variables. Assign the students to rewrite the program so that it has no globals at all, and to write up a comparison of the pros and cons of the global and no-global approaches. 2. Find or write a program with lots of globals. Introduce some subtle bugs into the program that have to do with global references. Assign the students to a) find and fix the bugs and b) explain how the code could have been written to prevent bugs like this from creeping in. 3. Find or write a program with a number of globals. For each global, ask the students to write an analysis comparing its usefulness and/or dangerousness. Are some of the globals worse than others? Why? 4. Find or write a program with some globals. Make up a change request from a user that will run into problems because of the globals. Assign the students to implement the change request. There are probably lots of other similar exercises one could make up. The idea is not to force students to do the right thing, but to get them to understand the differences between the better ways and the worse ways to write code. Incidentally, all of these exercises involve maintaining or re-writing existing code written by other people. Students don't usually do much of that, but when they get a real job, they find that maintenance is most of what they actually do, especially as junior programmers. Having to work in the real world of maintaining other people's code gives a student a better appreciation of the value of clean, modular, readable, documented code. Alan -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On 10/4/2011 9:07 PM, Alan Meyer wrote: ... and to write up a comparison of the pros and cons of the global and no-global approaches. ... Of course you'll need to be fair in evaluating the students comparisons. Some bright students are likely to come up with good reasons for using globals in some situations, and they might even be right. Or if they're not completely right, they might nevertheless be partly right. They should get high marks for that. You could even make up an exercise where the students are assigned to write a program that uses a global that could NOT be better implemented without globals. Then ask one or two of the authors of the better programs to defend their programs in front of the class. It's always a mistake to read student papers with preconceived, set in concrete ideas about what's right and what's wrong. Many years ago when I was teaching (philosophy, not computer science), in every class I taught there was always at least one student who taught me something I didn't know, or taught me that something I thought I knew was wrong. Alan -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On Tue, 04 Oct 2011 21:07:10 -0400, Alan Meyer wrote: Incidentally, all of these exercises involve maintaining or re-writing existing code written by other people. Students don't usually do much of that, but when they get a real job, they find that maintenance is most of what they actually do, especially as junior programmers. Having to work in the real world of maintaining other people's code gives a student a better appreciation of the value of clean, modular, readable, documented code. Well said that man!!! -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On Mon, 03 Oct 2011 21:27:12 -0700, alex23 wrote: rantingrick rantingr...@gmail.com wrote: Why? Well because many times i find myself wondering if this or that variable is local or global -- and when i say global i am speaking of module scope! The globalDOT cures the ill. Given your stated propensity for huge code blocks not chunked into functions, I'm not surprised you lose track of what is global, what is nonlocal etc. This is another clear advantage of small functions: you can view it all at once. For the rest of us, a variable is global if its referenced but not defined in a specific scope. There's no need for such verbose hand-holding. I'd say the wart is in your design practice rather than the language itself. Furthermore, rick's suggestion that all globals should be referenced using an explicit global namespace would become extraordinarily horrible in practice. Let's take a simple example from the shutil module: # From Python 2.5 shutil.py def copystat(src, dst): Copy all stat info (mode bits, atime and mtime) from src to dst st = os.stat(src) mode = stat.S_IMODE(st.st_mode) if hasattr(os, 'utime'): os.utime(dst, (st.st_atime, st.st_mtime)) if hasattr(os, 'chmod'): os.chmod(dst, mode) Under Rick's proposal, that would be written: def copystat(src, dst): Copy all stat info (mode bits, atime and mtime) from src to dst st = global.os.stat(src) mode = global.stat.S_IMODE(st.st_mode) if global.hasattr(os, 'utime'): global.os.utime(dst, (st.st_atime, st.st_mtime)) if global.hasattr(os, 'chmod'): global.os.chmod(dst, mode) Imported modules are variables like any other, and as they usually exist in the global scope, so they will all need to be explicitly referenced as global. This will get tiresome very quickly, and is a cure far worse than the disease, and alone is enough to disqualify this suggestion from serious consideration. Furthermore, globals in Python also includes the built-ins, so every reference to built-ins like len, sum, list, int, abs, etc. will also need an explicit reference, e.g. global.len, global.sum. (The alternative would be a significantly different name-lookup strategy: instead of names being local vs global or builtin, they would be local or builtin vs global. This will break monkey-patching.) -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
Steven D'Aprano steve+comp.lang.pyt...@pearwood.info wrote: Imported modules are variables like any other, and as they usually exist in the global scope, so they will all need to be explicitly referenced as global. This will get tiresome very quickly, and is a cure far worse than the disease, and alone is enough to disqualify this suggestion from serious consideration. But on the gripping hand, it is a clear triumph of Explicit is better than implicit. ;) -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On Tue, 04 Oct 2011 20:20:34 -0700, alex23 wrote: Steven D'Aprano steve+comp.lang.pyt...@pearwood.info wrote: Imported modules are variables like any other, and as they usually exist in the global scope, so they will all need to be explicitly referenced as global. This will get tiresome very quickly, and is a cure far worse than the disease, and alone is enough to disqualify this suggestion from serious consideration. But on the gripping hand, it is a clear triumph of Explicit is better than implicit. ;) I see your wink, but explicitness is not a binary state. You can have too much explicitness. Which would you rather? import math x = math.sin(1.2345) or: import the module called 'math' into the current namespace and bind that module to the name 'math' in the current namespace bind the name 'x' in the current namespace to the return result of calling the attribute named 'sin' in the object currently bound to the name 'math' in the current namespace using the float literal 1.2345 as the argument I'm thinking that the second version might get a bit annoying after a little while, no matter what the Zen says. Besides, based on the Zen, should we also write this? local.x = global.math.sin(1.2345) -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Is it possible to create C-style main function in Python? (for teaching purposes)
Hi! I'm looking for a trick or hidden feature to make Python 3 automatically call a main function but without programmers writing `if __name__ == __main__: ...` I found rejected PEP 299, but i thought that maybe there's something new already. Here's why I want such a thing: I'm teaching introductory programming course with Python. I've seen that global variables attract beginners like honey attracts bees and this makes teaching function parameters harder. When students learn functions, they usually write their function definitions and function applications in the same scope -- in top-level of the module (don't know the correct term for it). This has the downside, that any variable introduced in top-level is automatically visible in function definitions and I have hard time convincing students not to use those variables in functions directly. I've been thinking that it might be better for teaching if all program code would be in functions. This would make Hello World a bit more difficult, but would help teaching the real thing ie. functions. best regards, Aivar -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
Make something with http://metapython.org/ ? On Tue, Oct 4, 2011 at 3:21 AM, Aivar Annamaa aivar.anna...@gmail.com wrote: Hi! I'm looking for a trick or hidden feature to make Python 3 automatically call a main function but without programmers writing `if __name__ == __main__: ...` I found rejected PEP 299, but i thought that maybe there's something new already. Here's why I want such a thing: I'm teaching introductory programming course with Python. I've seen that global variables attract beginners like honey attracts bees and this makes teaching function parameters harder. When students learn functions, they usually write their function definitions and function applications in the same scope -- in top-level of the module (don't know the correct term for it). This has the downside, that any variable introduced in top-level is automatically visible in function definitions and I have hard time convincing students not to use those variables in functions directly. I've been thinking that it might be better for teaching if all program code would be in functions. This would make Hello World a bit more difficult, but would help teaching the real thing ie. functions. best regards, Aivar -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On 01/-10/-28163 02:59 PM, Aivar Annamaa wrote: Hi! I'm looking for a trick or hidden feature to make Python 3 automatically call a main function but without programmers writing `if __name__ == __main__: ...` I found rejected PEP 299, but i thought that maybe there's something new already. Here's why I want such a thing: I'm teaching introductory programming course with Python. I've seen that global variables attract beginners like honey attracts bees and this makes teaching function parameters harder. When students learn functions, they usually write their function definitions and function applications in the same scope -- in top-level of the module (don't know the correct term for it). This has the downside, that any variable introduced in top-level is automatically visible in function definitions and I have hard time convincing students not to use those variables in functions directly. I've been thinking that it might be better for teaching if all program code would be in functions. This would make Hello World a bit more difficult, but would help teaching the real thing ie. functions. best regards, Aivar It's not clear if you're asking for a new fork of the language, or just wanting to keep people from bad habits. Like it or not, there are plenty of globals already there, one of them being __name__ . All the built-ins are effectively global, and so is any function they define at top-level. Likewise any top-level class, and any symbols imported with import or with from/import. So I consider it impractical for the language to do something that self-discipline is required for. Is it explaining the if statement that's the problem? If so, you could have them do an unconditional main(sys.argv) at the bottom of their file, and not bother putting an if statement in front of it. Then when you get to user-written modules, you could introduce the if __name__ and explain its need. DaveA -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On Mon, Oct 3, 2011 at 1:14 PM, Dave Angel da...@ieee.org wrote: Is it explaining the if statement that's the problem? If so, you could have them do an unconditional main(sys.argv) at the bottom of their file, and not bother putting an if statement in front of it. Then when you get to user-written modules, you could introduce the if __name__ and explain its need. It's not a good idea to teach bad habits they'll just have to unlearn later on. Especially since they might not be paying attention when you talk about if __name__ and how to do it right. I would suggest giving them the whole if __name__ block as boilerplate and telling them they're not allowed to alter it. Then in a later class, explain its purpose. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On Oct 3, 2:14 pm, Dave Angel da...@ieee.org wrote: Like it or not, there are plenty of globals already there, one of them being __name__ . All the built-ins are effectively global, and so is any function they define at top-level. I keep wondering if that was another PyWart? I believe (and hindsight is 20-20) that all the built-in modules should have been protected by a top-level namespace. Something succicent, something like py... from py.archive import zipfile, tarfile from py.gui import Tkinter from py.markup import HTMLParser ...and voila, no more clashes with user defined modules! Likewise any top-level class, and any symbols imported with import or with from/import. So I consider it impractical for the language to do something that self-discipline is required for. Also for scoping. py count = 0 py def foo(): ... global.count += 1 py print count 1 Why? Well because many times i find myself wondering if this or that variable is local or global -- and when i say global i am speaking of module scope! The globalDOT cures the ill. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
Ian Kelly wrote: I would suggest giving them the whole if __name__ block as boilerplate and telling them they're not allowed to alter it. I would suggest not showing them if __name__ at all; instead encourage them to do this: def main(): ... ... main() You only need if __name__ == '__main__' if you want a .py file that can be used as either a module or a main program. Most of the time you *don't* need that. I consider it advanced usage that beginners shouldn't be confused with. -- Greg -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On 01/-10/-28163 02:59 PM, rantingrick wrote: On Oct 3, 2:14 pm, Dave Angelda...@ieee.org wrote: Like it or not, there are plenty of globals already there, one of them being __name__ . All the built-ins are effectively global, and so is any function they define at top-level. I keep wondering if that was another PyWart? I believe (and hindsight is 20-20) that all the built-in modules There's only one __builtins__ module, which is implicitly loaded, and contains tons of things which are effectively global, such as open, float, filter, sorted, etc. should have been protected by a top-level namespace. Something succicent, something like py... from py.archive import zipfile, tarfile from py.gui import Tkinter from py.markup import HTMLParser ...and voila, no more clashes with user defined modules! Gee, you just described a package. So why not say that the stdlib should have been done as a package of modules ? I don't know if I agree or not, just trying to keep things level. Likewise any top-level class, and any symbols imported with import or with from/import. So I consider it impractical for the language to do something that self-discipline is required for. Also for scoping. py count = py def foo(): ... global.count += py print count 1 Why? Well because many times i find myself wondering if this or that variable is local or global -- and when i say global i am speaking of module scope! The globalDOT cures the ill. DaveA -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On Mon, Oct 3, 2011 at 2:10 PM, rantingrick rantingr...@gmail.com wrote: Also for scoping. py count = 0 py def foo(): ... global.count += 1 py print count 1 Why? Well because many times i find myself wondering if this or that variable is local or global -- and when i say global i am speaking of module scope! The globalDOT cures the ill. def add_from_input(num_lines): total = global.sum(global.int(global.input()) for i in global.range(num_lines)) global.print(The total is, total) Yes, that's much better. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
On Tue, Oct 4, 2011 at 9:41 AM, Ian Kelly ian.g.ke...@gmail.com wrote: def add_from_input(num_lines): total = global.sum(global.int(global.input()) for i in global.range(num_lines)) global.print(The total is, total) That's pretty unfair to the globals. def add_from_input(param.num_lines): local.total = global.sum(global.int(global.input()) for tinyscope.i in global.range(param.num_lines)) global.print(The total is, local.total) FTFY. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
In article mailman.1702.1317670708.27778.python-l...@python.org, Ian Kelly ian.g.ke...@gmail.com wrote: It's not a good idea to teach bad habits they'll just have to unlearn later on. Absolutely correct. People who teach teachers how to teach call this the Law of Primacy (http://en.wikipedia.org/wiki/Principles_of_learning#Primacy), and (despite a lot of the religious psychobabble that comes with the territory) it really is true. Much better to just say, put this stuff at the end of your file and don't worry about it for now then to teach people the wrong way to do things. At some point, you'll get up to talking about modules and/or the magic double-underscore namespace. Then you'll have the opportunity to double back and explain what it means. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
rantingrick rantingr...@gmail.com wrote: Why? Well because many times i find myself wondering if this or that variable is local or global -- and when i say global i am speaking of module scope! The globalDOT cures the ill. Given your stated propensity for huge code blocks not chunked into functions, I'm not surprised you lose track of what is global, what is nonlocal etc. This is another clear advantage of small functions: you can view it all at once. For the rest of us, a variable is global if its referenced but not defined in a specific scope. There's no need for such verbose hand-holding. I'd say the wart is in your design practice rather than the language itself. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is it possible to create C-style main function in Python? (for teaching purposes)
Sorry for hijacking Alec's response but I didn't see the OP. Aivar Annamaa aivar.anna...@gmail.com wrote: I'm looking for a trick or hidden feature to make Python 3 automatically call a main function but without programmers writing `if __name__ == __main__: ...` One direct way is to call it from the command line: python -c import mymodule; mymodule.main() After your students have had to use that verbose form for a while, they'll be more than happy to add the boilerplate themselves to the end of their modules :) -- http://mail.python.org/mailman/listinfo/python-list
