Hot on the heels of the changes to the underlying Simplenote.py, Simplenote.vim is now Python 2 and 3 compatible. Ok, that’s a lie. The same fate befell me: I assumed it would be tricky and complex to do (not least because I needed to build a separate version of Vim with only Python 3), but in the end it was actually quite easy and I really should have done it sooner than fourteen months later.
Some of the key points this time round:
Using pyfile instead of embedded code
Simplenote.vim makes use of embedded python code identified with endmarkers, like so:
python <<< ENDPYTHON #python code here ENDPYTHON
but Vim requires you use the appropriate call for the version of python you have and will error if you call a version you don’t have. I.e. for python 3 you must use
python3 <<< ENDPYTHON #python3 code here ENDPYTHON
This potentially was going to lead to huge chunks of duplicated code as you’d need a setup like follows:
if has("python") python <<< ENDPYTHON #python code here ENDPYTHON elseif has("python3") python3 <<< ENDPYTHON #Very similar python3 code here ENDPYTHON endif
Fortunately, at least I think so, using these
has calls means Vim will load the first available python, but not both, which is what I want. I’m not sure how many people are likely to have vim compiled with support for both though; it was only just recently when I came across the first person who had python 3 support instead of python 2. I guess I’ll await the bug reports.
To get around the duplication I used
pyfile instead, like follows:
if has("python") execute 'pyfile ' . s:scriptpath . "/samefilefor2and3.py" elseif has("python3") execute 'py3file ' . s:scriptpath . "/samefilefor2and3.py" endif
I thought this would be my stumbling block, as Python 3 no longer has a
cmp function for
sort, only accepts a much more simplistic
key, and Simplenote.vim uses quite an extensive compare function for sorting notes in the list index. Fortunately, from version 3.2 onwards there is a
cmp_to_key function provided by
functools so I could just do:
I think I can be pretty confident that anyone who has Vim compiled against Python 3 only will have a recent version of Python 3.
Python 3 changes that work fine under Python 2
iteritemsdoesn’t exist under Python 3, instead you just call
items. For the Simplenote.vim use of
iteritems, using just
itemsunder Python 2 worked fine.
- Python 3 requires you use
mapto return the actual content (otherwise you just get a map object). Python 2 doesn’t require this, but including it anyway causes no harm.
- No more
has_key, but that has been depreciated for a long time anyway. Just use
ininstead, works everywhere.
Really the only excuse for not writing Python 2 and 3 compatible code is laziness.