[ANN] nyacc version 0.86.4 released

[Matt Wette]

NYACC, for Not Yet Another Compiler Compiler, is set of guile modules for
generating parsers and lexical analyzers.  It also provides sample parsers
and pretty-printers using SXML trees as an intermediate representation.

It provides a decent C parser and a `FFI Helper' tool to help create
Guile Scheme bindings for C-based libraries.

It provides (partially implemented) compilers based on above mentioned
parsers to allow execution with Guile as extension languages.

---------------------------

Updates for version 0.86.4:
1) Made significant changes to the C99 parser grammar so that it is more
   robust when parsing attribute specifiers - e.g., __attribute__((packed))
2) Changed scripts/compile-ffi.scm so that dependent ffi and associated
   scm files are checked and (re)compiled if outdated
   (needs some work still : sometimes compiles twice)
3) Fixed fh-wrap, fh-unwrap bugs in system/ffi-help-rt.scm
4) Worked misc issues on example language parsers (octave, modelica).

Note: I will now start to work on cleaning up how c99 handles comments.
      The goal is to carry code-comments as attributes in the AST.

Interesting tidbit for YACC hackers: When I added __attribute__ handling
"everywhere" I found that I was getting a number of shift-reduce conflicts.
So I set up a precedence rule that looks something like:
  (prec< 'shift-on-attr "__attribute__" 'reduce-on-attr)
So in productions where I want to shift on "__attribute__" I use a RHS like
  (foo bar ($prec 'shift-on-attr))
and in productions where I want to reduce on "__attribute__" I use a RHS like
  (foo baz ($prec 'reduce-on-attr))
where RHS = "right hand side of production rule"

---------------------------

NYACC maturity is beta level.

NYACC is free software; the full source distribution is available through

* the tarball repository:
    https://download.savannah.gnu.org/releases/nyacc/

* the git repository:
    git://git.savannah.nongnu.org/nyacc.git

home page, project page and user's guide:
* http://www.nongnu.org/nyacc
* https://savannah.nongnu.org/projects/nyacc
* http://www.nongnu.org/nyacc/nyacc-ug.html

For support see:
    https://savannah.nongnu.org/support/?group=nyacc