=head1 Perl 6 Parser Stuff in the Pugs Repo

Welcome to pugs/src/perl6.  This is the home of STD.pm6, the canonical
Perl 6 grammar, which is written in Perl 6 (of course).  It is also the
home of viv, a retargettable Perl 6 metacompiler which can translate
STD.pm6 into Perl 5 (and eventually other things).  The metacompiler
relies on STD.pm6 to parse itself, requiring a stored bootstrap version
of the compiled STD.pm.  This is also the home of Cursor, the canonical
implementation of the Perl 6 rules engine; it co-evolves with viv and
executes the actual rules.  This is also the home of a collection of
minor tools used in the development of STD.pm6 and viv.

=head1 Prerequisites

You'll need the following Perl bits to run stuff:

* Perl 5.10.0 or later in PATH

* YAML::XS       (e.g. sudo apt-get install libyaml-libyaml-perl)

* Moose          (e.g. sudo apt-get install libmoose-perl)

* File::ShareDir

=head1 Running Stuff

You can get started by using the Makefile command, C<make>.  This will convert
the Perl 6 grammar into a Perl 5 module, C<STD>.  C<STD> has a fairly simple
API; just call C<parse> as a class method with the source you want to parse as
a parameter, and look at the result.  Another module, C<Actions>, is provided
which converts C<STD>'s output into a more object-oriented form; see C<viv>'s
source for an example of the latter's use.  (Both methods have more options
when you need them.)

The following tools are provided which leverage the power of C<STD>:

* C<tryfile> parses a file of Perl 6 code and reports 'ok' or 'FAILED', plus the
  time taken and memory used.

* C<std> does the same, but also tests Actions.

* C<redspans> parses a file, reporting what rules matched which tokens.

* C<reds> appears to be an older, non-working version of redspans.

* C<teststd> uses STD to check the syntax of the Perl 6 Specification Tests.

* C<tloop> is an interactive STD syntax checker.

* C<vill> is a prototype STD-based LLVM-based Perl 6 JIT compiler.

* C<viv> is a retargettable metacompiler for the static subset of Perl 6.

* C<std_hilite/STD_syntax_highlight> is a syntax highlighter with multiple output formats.

See the headers of the respective programs for more details, and don't hesitate
to ask around as quite a bit of this is underdocumented.

=head1 Working the Makefile

To regenerate perl 5 files from perl 6 STD.pm6, STD_P5.pm6, and Cursor.pm6
changes:

 make

To do that, but without running the self test (bootstrap):

 make fast

To remake only one file:

 make STD.pmc

To update the first stage, allowing new STD.pm6 or Cursor.pm6 features to be
used while building future versions of STD.pm6 or Cursor.pm6:

 make reboot

To remove all generated files:

 make clean

To test the ability to parse the Perl 6 test suite (this is a very effective
regression test, but B<slow> - 20-75 minutes; also, it runs in a snapshot of
the current directory, so you can continue hacking):

 make snaptest