commit 71d2f2fb3c99e9fd38d7884991fc677cdf505003
author Mathieu Boespflug <mboes@tweag.net> Thu Feb 22 14:54:47 2018 +0100
committer Laurent Le Brun <laurentlb@gmail.com> Thu Feb 22 14:54:47 2018 +0100
tree 243b23b2e799ffbbc90b1eec4053aea4fe11fb1b
parent 4cc51480f36eac2e4a1df07a1cab2f7f14c47dee

Use a single evaluation enviroment for rules. (#84)

The rule extractor interprets Skylark code as Python, in an
environment with most Skylark globals and primitives stubbed out. It
was doing so in two environments, one for globals and one for locals.
But the Python documentation has this to say:

> If two separate objects are passed as globals and locals, the code
> will be executed as if it were embedded in a class definition.

This means that using two environments can have suprising results. One
of which is that calling recursive functions don't work, whereas it
works in Skylark or at the Python top-level. This also means that
calling a function `foo()` that itself depends on a function `bar()`
in the same Skylark file doesn't work.

So we instead `exec ...` in a single environment. We infer new
definitions contained in the input file by diffing the hold state and
the new state of the environment.