annotate doc/README @ 40273:3b275f549777

rust: exposing in parsers module

To build with the Rust code, set the HGWITHRUSTEXT
environment variable.

At this point, it's possible to instantiate and use
a rustlazyancestors object from a Python interpreter.

The changes in setup.py are obviously a quick hack,
just good enough to test/bench without much
refactoring. We'd be happy to improve on that with
help from the community.

Rust bindings crate gets compiled as a static library,
which in turn gets linked within 'parsers.so'

With respect to the plans at
https://www.mercurial-scm.org/wiki/OxidationPlan
this would probably qualify as "roll our own FFI".
Also, it doesn't quite meet the target of getting
rid of C code, since it brings actually more, yet:

- the new C code does nothing else than parsing
  arguments and calling Rust functions.
  In particular, there's no complex allocation involved.
- subsequent changes could rewrite more of revlog.c, this
  time resulting in an overall decrease of C code and
  unsafety.

Mercurial's documentation is kept in reStructuredText format, which is
a simple plain text format that's easy to read and edit:

  http://docutils.sourceforge.net/rst.html

It's also convertible to a variety of other formats including standard
UNIX man page format and HTML. You'll need to install Docutils:

  http://docutils.sourceforge.net/

Use the Makefile in this directory to generate the man and HTML pages.