Friday, July 10, 2015

AtLast ForthLang

User Manual

RaspberryPi Install

Pez is based on AtLast

Pez is a small, lightweight, 100% C (for now), embeddable or standalone,
public domain, portable, highly nonstandard dialect of Forth.  It was
originally based on the Atlast system (see doc/CREDITS for more
information), but the feature set has been expanded significantly and
there are flagrant breaks with Forth compatibility.

The primary goal of the Pez project, much like the goal of the Atlast
project, is to bring dead-simple scriptability and dynamism to otherwise
static code, with a focus on user-level scripting of applications.
There are a number of compile-time options for trimming down and
limiting in the case of untrusted input, and also a large number of
OS-level facilities both added and planned.  Pez is also designed to
work well as a stand-alone language for general-purpose coding.  And
it's designed to be fun.

I highly recommend having a look at doc/historic/atlast.pdf, written by
Mr.  Walker in 1990, especially the introduction which is still
shockingly relevant now, about 20 years later.

There are a number of benefits to adding user-level scripting to an
application.  You get a free doman-specific language to expose to users
however you see fit.  You get a free configuration file parser in the
same language as your application's DSL.  You get a dynamic internal
scripting language a la LUA.  You get a safe, plain-text, cross-platform
language for communicating between your applications.  It can even be
used as a complete, full-featured standalone language.  And it's
lightweight to boot:  running on a 64-bit Linux, I'm looking at about 568k
of memory for the REPL for a full system.

Pez has added to the Atlast system a number of features:
* Portability to 64-bit platforms
* A Foreign Function Interface, for dynamically loading libraries to
  interface with system libraries.
* More complete access to standard system calls, such as fork(), exec(),
* Regular expression support.
* Garbage collection.
* Numerous small improvements, and more large improvements on the way.  See

I certainly hope that you find this codebase to be as useful and as much
fun as I have.

If you're a Ruby fanatic, by the way, there is also Rupez, which lets
you talk to libpez by means of the fantastic RubyFFI.  See for the code.

Pete Elmore


tags:  777ForthLang   777AtLast

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