h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: Forth - the programming language - A2681868
Author: Gnomon - U151503

This is an entry which I hope does justice to Forth, which is not my favourite programming language.

I prefer it to *this* langauge: http://www.catb.org/~esr/intercal/stross.html * 10^6

Hi Gnomon,

Excellent article as usual!

But, you write an article on Forth, and do not mention the Jupiter ACE? It appeared around the time of the ZX Spectrum and had a very brief life before disappearing just as quickly. Its passing should not be forgotten however..

Woodpigeon (who hasn't thought about the Jupiter ACE in 20+ years and is mystified how he could have retained such useless information for so long).

Hi WOodpigeon. I know that a few different computers have been produced over the years that "run on Forth". The Forth Inc company even make microprocessors with the basic Forth functions built in! So I considered putting in the Jupiter Ace, but decided I didn't want to mention every single Forth computer ever made.

But I suppose the Jupiter Ace was well enough known that the average Joe Soap computer buyer would have heard of it, so I'll think again about mentioning it.

OK, I've added a reference to the Jupiter Ace.

Ah, and very nicely written too, I might add!

Nice entry - maybe a bit long for general readership?

Boeing (the airplane company) uses Forth as part of the functional test kernel software for aircraft electronics. The Forth interpreter for the 68K processor family uses only about 6K of ROM (or EEPROM or Flash) and a few hundred bytes of RAM. I was involved in this personally.

The language that I have found that is most similar to Forth is PostScript, which usually is not written by humans. for example, the word "inch" which muliplies the current stack entry by 72 (points per inch) in PostScript is

/inch {72 mul} def

or in Forth is

: inch 72 * ;

Interpeted languages are still quite widely used today due to security concerns - a piece of Javascript can be safely interpreted and executed from the safe 'sandbox' of one's browser - and compatibility issues. Forth however had some serious drawbacks; the most insurmountable I would say is that reliance on the stack allowed many programs to become totally unreadable.

Thanks, Dr M!

Looks good to me!


Mikey, who remembers programming in some awfully odd languages, but not this one

Your Guide Entry has just been picked from Peer Review by one of our Scouts, and is now heading off into the Editorial Process, which ends with publication in the Edited Guide. We've therefore moved this Review Conversation out of Peer Review and to the entry itself.

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Yay!

Note to whoever gets the task of sub-editing this:

Don't play around with the spaces or punctuation in the Forth statements themselves. They are all part of the language and can't be changed or omitted in any way.

Not to worry - I was a programmer once upon a time. Never encountered Forth, though. (I saw the references to stacks and memory addresses and thought: 'C' )

quizzical (sallying forth )