Add compatibility function Compat.LinAlg.checksquare

[andreasnoack]

Fixes #168

[yuyichao]

Shouldn't this be better handled by a unexported Compat.checksquare or Compat.LinAlg.checksquare function?

[andreasnoack]

Maybe. What are the trade-offs?

[yuyichao]

An actual name is much more reliable than rewriting the ast with a macro and should be the preferred way.

[yuyichao]

The down side is of course that you can't just remove the @compat when dropping support for old julia version and need to replace Compat or Compat.LinAlg by Base.LinAlg instead.

[andreasnoack]

I can see that, but it is compelling that you can just use latest syntax + @compat. Do you see any specific vulnerabilities with the rewrite function I've written?

[yuyichao]

The fact that you need to patch using (and missing import and importall)? In general, I think we only use @compat to bridge syntax changes and while there are changes that are tricky to classify, a renaming like this is certainly not one of those.

[yuyichao]

These can be const checksquare = Base.LinAlg.chksquare and const checksquare = Base.LinAlg.checksquare (or import Base.LinAlg.checksquare).

[andreasnoack]

@yuyichao Thanks for the comments. I've updated the PR.

[yuyichao]

LGTM. =)