[Buildroot] [PATCH 2/3] graph-depends: split off get_version/get_depends into pkgutil.py

[Yann E. MORIN <yann.morin.1998@free.fr>]

Thomas DS, All,

On 2017-02-05 22:27 +0100, Thomas De Schampheleire spake thusly:
> On Sun, Feb 5, 2017 at 10:13 PM, Yann E. MORIN <yann.morin.1998@free.fr> wrote:
> > Thomas DS, All,
> >
> > On 2017-02-03 21:57 +0100, Thomas De Schampheleire spake thusly:
> > [--SNIP--]
> >> +import pkgutil
> >
> > So, I always claimed I was not a Python expoert, but should we not do:
> >
> >     from okgutil import get_versions get_depends
> >
> > of something similar?
> 
> Both methods are technically possible, and I think this is partially a
> matter of personal/project preference, and partially some general
> guidelines.

Ok for me, then.

Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

Regards,
Yann E. MORIN.

> When using 'import foo', any symbol used from foo needs to be
> qualified explicitly, i.e. foo.one, foo.two. You could consider it as
> making a namespace accessible but keeping everything inside that
> namespace.
> 
> With 'from foo import one, two' you allow future usages to be done
> without referring to foo anymore. I consider it as 'using namespace
> foo' in C++ terminology.
> 
> One could argue about performance of one vs the other, but I think it
> hardly matters (although I did never measure that).
> 
> Personally, I'm more in favor of 'import foo' and keeping explicit
> references for following reasons:
> 1. it makes it clear inside the code where a symbol comes from -- in
> general I consider 'using namespace foo' a bad thing.
> 2. maintainability: if more functions are added to foo and used from a
> script, the list in the import statement becomes larger and larger, to
> possibly ridiculous proportions.
> 
> There is one case where I do use 'from Foo import Foo' and that is
> when Foo is a class that is saved in its own equally-named file
> Foo.py. In this case, Foo.Foo seems a bit redundant and it makes sense
> to make the class Foo directly accessible.
> 
> I found the following 100% reliable reference (ahum) about the topic:
> http://stackoverflow.com/questions/710551/import-module-or-from-module-import
> 
> 
> >
> > [--SNIP--]
> >> @@ -204,7 +157,7 @@ def get_all_depends(pkgs):
> >>      if len(filtered_pkgs) == 0:
> >>          return []
> >>
> >> -    depends = get_depends(filtered_pkgs, rule)
> >> +    depends = pkgutil.get_depends(filtered_pkgs, rule)
> >
> > And then just use get_depends here?
> >
> >>      deps = set()
> >>      for pkg in filtered_pkgs:
> >> @@ -377,7 +330,7 @@ if check_only:
> >>      sys.exit(0)
> >>
> >>  dict_deps = remove_extra_deps(dict_deps)
> >> -dict_version = get_version([pkg for pkg in allpkgs
> >> +dict_version = pkgutil.get_version([pkg for pkg in allpkgs
> >
> > Ditto?
> >
> >>                                  if pkg != "all" and not pkg.startswith("root")])
> >>
> >>  # Print the attributes of a node: label and fill-color
> >> diff --git a/support/scripts/pkgutil.py b/support/scripts/pkgutil.py
> >> new file mode 100644
> >> index 0000000..a911123
> >> --- /dev/null
> >> +++ b/support/scripts/pkgutil.py
> >> @@ -0,0 +1,55 @@
> >> +#!/usr/bin/env python
> >
> > As I understand it, this file is not supposed to be standalone, but just
> > a "library" of functions?
> >
> > So it should not need to have the sha-bang line, yes?
> 
> Yes, you are right, that line is not necessary.
> 
> >
> > Otherwise, I'm not opposed to this.
> 
> Thanks!

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