README

This is exyapps, a LL(1) parser generator.  

It is derived from yapps ( http://theory.stanford.edu/~amitp/yapps/
) by Amit J. Patel <amitp .at. cs.stanford.edu>.  He is no longer
maintaining yapps, and there seem to be several forks out there,
all with varying version numbers.  Matthias Urlichs <smurf .at.
debian.org> made some patches for Debian; this copy was derived
from the Debian distribution, by Mark Sienkiewicz <sienkiew .at.
stsci.edu> at the Space Telescope Science Institute.

Some of the modifications that changed yapps to exyapps introduced the
possibility of a fundmamental incompatibility with existing yapps2-based
parsers.  This, coupled with the non-linear version numbers of the
various forks, prompted me to rename yapps to exyapps.


New Features of exyapps relative to yapps
--

- The generated parser no longer needs to have exyapps installed at
run time.  The entire runtime is incorporated into the parser.  

- You can pass a data object to the parser for it to use as
parser-global data.  I know the OO way is to subclass the parser
object and hope you don't accidentally override anything important,
but I find easier to use in a particular application I have in mind.


Installing / using exyapps
--

        python setup.py install

        cd /your/project

        exyapps my_grammar.exy

	it will create a file named my_grammar.py


Modifying exyapps
--

The exyapps parser is written in exyapps.  If you want to modify
yapps_grammar.g, use this procedure:

	- install the current version of exyapps

	- rm exyapps/grammar.py

	- make

This will re-generate grammar.py, which will be your new parser.  You can
install it somewhere else to try it.


VIM
--

To recognize .exy files and treat them as python, put this in .vimrc

	autocmd BufRead,BufNewFile *.exy                set filetype=python

This is not exactly an ideal configuration, but it is good enough.


What is here?
--

Makefile
yapps_grammar.g
        yapps_grammar.g is the source code for exyapps/grammar.py

doc
        latex source for the documentation - this is the original
	document by Amit Patel; it has not been updated to reflect
	the exyapps modifications.

examples

exyapps
	the exyapps package that gets installed - this is only need
	to compile the parser; you do not need to install exyapps
	to run a generated parser.

scripts
        "exyapps" command that compiles a parser into python code.

setup.py
	regular setup.py using distutils

test
        not actual tests, but apparently some interesting input to
        run through the parser for testing