Moving to an OOP model from an classically imperitive one

[Mark Lawrence]

On 23/04/2014 21:57, tim.thelion at gmail.com wrote:
> Hello,
>
> I am currently writting a program called subuser(subuser.org), which is written as classically imperative code.  Subuser is, essentially, a package manager.  It installs and updates programs from repositories.
>
> I have a set of source files https://github.com/subuser-security/subuser/tree/master/logic/subuserCommands/subuserlib which have functions in them.  Each function does something to a program, it identifies the program by the programs name.  For example, I have an installProgram function defined as such:
>
> def installProgram(programName, useCache):
>
> Now I've run into a flaw in this model.  There are certain situations where a "programName" is not a unique identifier. It is possible for two repositories to each have a program with the same name.  Obviously, I could go through my code and replace all use of the string "programName" with a tuple of (programName, repository).  Or I could define a new class with two attributes: programName and repository, and pass such a simple object arround, or pass a dictionary.  However, I think this would be better solved by moving fully to an OOP model.  That is, I would have a SubuserProgram class which had methods such as "install", "describe", "isInstalled"...
>
> There is one problem though.  Currently, I have these functions logically organized into source files, each between 40 and 170 LOC.  I fear that if I were to put all of these functions into one class, than I would have a single, very large source file.  I don't like working with large source files for practicall reasons.  If I am to define the class SubuserProgram in the file SubuserProgram.py, I do not want all <https://github.com/subuser-security/subuser/blob/master/logic/subuserCommands/subuserlib/run.py#L162> of run.py to be moved into that file as well.
>
> I thought about keeping each method in a separate file, much as I do now, something like:
>
> ###################
> #FileA.py
> ###################
> def a(self):
>    blah
>
> ###################
> #FileB.py
> ###################
> def b(self):
>    blah
>
> ###################
> #Class.py
> ###################
> import FileA, FileB
> class C:
>    a=FileA.a
>    b=FileB.b
>
> This works, but I find that it is hard to read.  When I come across FileA, and I see "self" it just seems very confusing.  I suffer a bout of "who-am-i"ism.
>
> I asked on IRC and it was sugested that I use multiple classes, however I see no logical way to separate a SubuserProgram object into multiple classes.
>
> So I thought I would seek your advice.
>
> Tim
>

You're writing Python, not Java, so put your code into one file and stop 
messing about.

-- 
My fellow Pythonistas, ask not what our language can do for you, ask 
what you can do for our language.

Mark Lawrence

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