Properly sort versions in "emsdk list"

[orestisfl]

This uses LooseVersion from distutils, here is the doc:

Version numbering for anarchists and software realists. Implements the
standard interface for version number classes as described above. A
version number consists of a series of numbers, separated by either
periods or strings of letters. When comparing version numbers, the
numeric components will be compared numerically, and the alphabetic
components lexically.
...
In fact, there is no such thing as an invalid version number under
this scheme; the rules for comparison are simple and predictable, but
may not always give the results you want (for some definition of
"want").

I believe that this should be available in all possible configurations of python, I checked with python2 & 3 on linux. If not, an easy workaround is to catch ImportError and set LooseVersion=None.

Comparison:
    Before   |   After
    1.39.9       1.39.16
    1.39.8       1.39.15
    1.39.7       1.39.14
    1.39.6       1.39.13
    1.39.5       1.39.12
    1.39.4       1.39.11
    1.39.3       1.39.10
    1.39.2       1.39.9
    1.39.16      1.39.8
    1.39.15      1.39.7
    1.39.14      1.39.6
    1.39.13      1.39.5
    1.39.12      1.39.4
    1.39.11      1.39.3
    1.39.10      1.39.2
    1.39.1       1.39.1
    1.39.0       1.39.0
    1.38.48      1.38.48
    1.38.47      1.38.47
    1.38.46      1.38.46
    1.38.45      1.38.45
    1.38.44      1.38.44
    1.38.43      1.38.43
    1.38.42      1.38.42
    1.38.41      1.38.41
    1.38.40      1.38.40
    1.38.39      1.38.39
    1.38.38      1.38.38
    1.38.37      1.38.37
    1.38.36      1.38.36
    1.38.35      1.38.35
    1.38.34      1.38.34
    1.38.33      1.38.33

[sbc100]

Great!

Sadly I believe some distros such as Ubuntu stopped shipping distutils. We recently had to remove a use of distutils from emscripten itself for this reason: emscripten-core/emscripten#10943.

Perhaps a basic re-implementation would be better here?

[orestisfl]

Wow that's absurd.

I see the possible alternatives, please select one:

• Try-catch ImportError, set LooseVersion=None (or use a variable to store the sorting key) will fall-back to default sorting
  • Easiest but fall-back is suboptimal
• Try-catch ImportError, fall-back to custom implementation
  • Essentially split at dots, convert each element to int, do not panic at non-int strings
• Custom implementation without even trying to import LooseVersion

[sbc100]

I bet we can write a good enough version of this in 3 or 4 lines of python, no?

It doesn't need to handle all the possible cases... we could probably start with something like: lst.sort(key=lambda s: [int(x) for x in s.split('.')]).. maybe not quite that simple but its starting point.

[orestisfl]

Up, WDYT?

[orestisfl]

This doesn't handle all possible cases (but at least it doesn't crash) and it should be enough for the versioning used in this project

[kripken]

This looks good to me, wdyt @sbc100 ?