readme: separate out the "quick start" so it really is quick

[gnprice]

No description provided.

[o11c]

Suggest that this wait until at least #721 is merged and probably #732 as well.

As far as I know, all important environments have python3, pip3, etc. so we should use that throughout. Also add comments about "yes, mypy runs on python3 even if you are checking python2 code", and once #732 is done remove the comment about python2 mode being unusable.

Also, since the packaged version is so old, we should probably use a git URL, such as what I put in my requirements.txt here, though likely we should include a @master for completeness.

[o11c]

Actually, should use python3 -m pip to be sure the version matches.

[refi64]

@o11c IMO, if the person has multiple Python 3 versions installed, they already know how to invoke pip.

[o11c]

IME, it's not intuitive that pip3.2 install --upgrade pip (which pip spams you until you do) will result in changing pip and pip3 to be 3.2 instead of the newest version.

[refi64]

IME

"In my experience"? Sorry, I'm bad at abbreviations... ;)

Also, I don't really get what you're saying...I mean, what does that have to do with running pip?

[o11c]

"In my experience"? Sorry, I'm bad at abbreviations... ;)

Yes.

Also, I don't really get what you're saying...I mean, what does that have to do with running pip?

It is quite likely that a user, in the course using pip, will unwittingly end up such that pip3 install mypy-lang followed by python3 <something that needs mypy or typing> will fail with ImportErrors (or worse, silently use the wrong module, leading to strange errors (or lack of expected errors) later on). Whereas python3 -m pip install mypy-lang will always work and DTRT.

[JukkaL]

Hmm maybe pip3 should be the default thing to recommend. Anybody care to check how things are on major platforms (OS X, Windows, Ubuntu 14.04 and newer) when using Python 3? On OS X we should probably consider both the official package from python.org and Homebew.

Here's one data point: On Ubuntu 14.04 pip is the Python 2 version. pip3 is available in the optional package python3-pip. Of course, when using virtualenv with Python 3.x pip will be the Python 3 version.

[o11c]

virtualenv always does pip -> pip3 -> pip3.X symlinks (or copies) though.

[JukkaL]

I've decided to recommend pip3 first. Still not 100% sure about this and we can iterate on this once we get more data.