Extend the python lexer for python3

[thomasboyt]

From what I've seen so far, the lexer seems to work for most Python 3 syntax, with the exception of the new yield from statement in Python 3.3: https://docs.python.org/3/whatsnew/3.3.html#pep-380-syntax-for-delegating-to-a-subgenerator

looks like this is because the from keyword immediately kicks the lexer state into "importing" mode, so the fix should be relatively simple: https://github.com/jneen/rouge/blob/master/lib/rouge/lexers/python.rb#L98-L101

I'll take a look at a PR for this soon, but wanted to leave a comment in case I didn't get the chance to come back to this issue :)

[thomasboyt]

ack, nevermind, someone did this already! what I get for searching issues instead of PRs :p https://github.com/jneen/rouge/pull/324

[rumpelsepp]

raise ... from also causes problems.

raise RuntimeError('Object cannot be packed') from e

[mnakama]

@rumpelsepp are you using the latest git code? I thought I fixed yield and raise in #324 .

[robin850]

(Hi there! I guess this issue can certainly be closed thanks to #324 and https://github.com/jneen/rouge/commit/81c08594e8ef08fcc16d5b3968de037321ca49af 😊 )

[miparnisari]

This can be closed too @pyrmont

[pyrmont]

Thanks @robin850 and @miparnisari :)