pct user docs

[Pavlo Korzhyk]

> What exactly needs to be written in order to finish the pct user doc
> milestone? Can any of the above be part of it?
> I'm happy to work on things, but I need some input on what is needed.

I can share my experience, as a user who investigated the use of PCT in 0.7.0-1
Series of articles from parrotblog was the only tutorial documentation
I was able to find.
It shows that you have to use a mix of PIR and NQP. With most tricky
parts (like symbol table)
done in low-level assembly-like language.
Alternative approach is to write a {my HLL} to PIR compiler in perl
and forget about PCT at all.
Keeping that old way in mind:
* NQP looks like reinventing the wheel
* using PIR to write a compiler looks as a jump back to a stone age
without languages like Perl or C++.

This is how it looks from the point of view of a newbie
(I spent several days reading the docs and decided to stick with perl
for a quick start. Later it could become reasonable to rewrite my code
and get a HLL->PAST compiler).

Some languages from tar.gz releases also use ANTLR or bison/yacc instead of PCT.

So to improve the PCT docs and make more people use it I propose:
1) add more information on how to use parts of PCT in c++/perl/java/python/etc
2) redesign the docs so others will not think that PCT are of little use.

Suggestions and comments are welcome, since I am still in doubt what
tools to use.


Regards,
Pavlo