Comments on: A tiny interpreter for a stack-based language

By: Link Backlog | Programmer's Log

Link Backlog | Programmer's Log — Tue, 06 Jan 2009 22:34:55 +0000

[...] A tiny interpreter for a stack-based language Writing an interpreter in Python. [...]

By: Hans Nowak

Hans Nowak — Mon, 05 Jan 2009 23:38:42 +0000

Ah, yes, Poplog… I wrote about it a few years ago. Here are the links to those posts:

http://zephyrfalcon.org/weblog2/arch_e10_00560.html#e562

http://zephyrfalcon.org/weblog2/arch_e10_00560.html#e563

I wonder if it has evolved since then? I’ll have to take a look.

By: Nico

Nico — Mon, 05 Jan 2009 23:34:55 +0000

Another not very known but mature stack-based language is Pop-11. It’s the base of the Poplog VM that also include implementations of Common Lisp, Prolog, Scheme and SML. Used for many years for AI, it was open sourced some years ago. Available for a number of OSs, can be found at: http://www.cs.bham.ac.uk/research/poplog/freepoplog.html

Pop-11 is very funny to program in, allowing things that are impossible in most other languages.

A curious detail is that assignement is done from left to right:

5 -> x;

It’s done through the user stack, so it could be splitted:

5;
-> x;

Although its called VM, Poplog isn’t an interpreter or uses bytecode, but it’s incrementally compiled.

By: Hans Nowak

Hans Nowak — Mon, 22 Dec 2008 17:13:31 +0000

Yes, the Python VM is stack-based as well… but people don’t usually program in it directly.

By: Evgueni

Evgueni — Mon, 22 Dec 2008 16:48:37 +0000

I could be mistaken, but isn’t Python itself uses a stack machine inside (with appropriate bytecodes for it)

By: Hans Nowak

Hans Nowak — Sun, 21 Dec 2008 19:25:17 +0000

You are right. I renamed this class, but forgot the __main__ block. Will fix.

By: Sidhath

Sidhath — Sun, 21 Dec 2008 19:23:06 +0000

Possible Bug.

if __name__ == “__main__”:

e = Engine()

Shouldn’t this be:

e = Interpreter()

Sorry if I’m wrong…

By: Tim Hoffman

Tim Hoffman — Sun, 21 Dec 2008 13:56:42 +0000

Hi Hans

One very widely available (though most people don’t use it directly ;-)
stacked based language that you should mention is postscript.

Whole OO systems including mutliple inheritance and delegation have been built in it. (A really good example was TNT which ran on NeWS from Sun) a totally awesome system imho ;-)

Cheers