FORTH is a _(low-level) *(functional)-like *(programming language) for a
stack-based _(VM) model, invented by _(Chuck Moore). It is a very
interesting language to study, both for its achievements and its shortcomings.

Forth is fully reflective and self-containing; the Forth parser (the so-called "outer interpreter") is written in Forth and can be modified at any time. Thus, at least potentially, Forth can have any syntax.

Central to Forth is the notion of a "word", corresponding to a function in other languages. A Forth program, after parsing, is nothing but a list of words, executed consecutively by the "inner interpreter", the core of Forth.

Forth is untyped, much in the same way that _(Assembly) is.

<UL CLASS="links">
<LI>_("forth.org" | http://www.forth.org/), _("FTP Site" | ftp://ftp.forth.org/),
_("German FTP Mirror"
 | ftp://ftp.uni-bremen.de/pub/languages/programming/forth/Taygeta-Archive)</li>
<LI>_("The Evolution of Forth" | http://www.forth.com/Content/History/History1.htm),
a Forth history by Charles H. Moore (_(Chuck Moore)), Elizabeth D. Rather, Donald R. Colburn</li>
<LI>_("FORTH - A Language for Interactive Computing" | http://www.ultratechnology.com/4th_1970.html):
  The original FORTH paper by _(Chuck Moore)</li>
<LI>_("Forth - The Early Years" | http://www.colorforth.com/HOPL.html) another Forth history
from its inventor.
<LI>_("Forth, Inc." | http://www.forth.com/): founded by the authors of Forth</li>
<LI>_("Ultratechnology.com" | http://www.ultratechnology.com/): Jeff Fox's WWW site</li>
<LI>_("Taygeta Scientific Incorporated" | http://www.taygeta.com/)</li>
<LI>_("FAQ" | http://www.faqs.org/faqs/computer-lang/forth-faq/) written by the good people at comp.lang.forth</li>
<LI>_("cera2.com" | http://www.cera2.com/softd/forth.htm)</li>
<LI>_("eg3.com" | http://www.eg3.com/softd/forth.htm)</li>
<LI>_("Stack Computers: the new wave" | http://www.ece.cmu.edu/~koopman/stack_computers/index.html): a freely available online book by Philip J. Koopman, Jr.</li>
<LI>_("M. Anton Ertl's WWW site" | http://www.complang.tuwien.ac.at/anton/home.html)</li>
<LI>_("Patriot Scientific Corp." | http://www.ptsc.com/): FORTH chip maker</li>
</ul>

<UL CLASS="implementations">
<LI>_("Gforth" | http://www.jwdt.com/~paysan/gforth.html): GNU Forth</li>
<LI>_("PFE" | ftp://ftp.taygeta.com/pub/Forth/)</li>
<LI>_("MOPS" | http://www.netaxs.com/~jayfar/mops.html): A FORTH with _(OO) extensions,
and integration with the Macintosh
environment.</li>
<LI>For various implementations see
_("comp.lang.forth.repository" | http://forth.sourceforge.net/)</li>
</ul>