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Given a string, create word with that name (in ANS Forth)?

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  Given a string, create word with that name (in ANS Forth)? Alex Dowad <alexinbeijing@gmail.com> - 2016-09-11 06:12 -0700
    Re: Given a string, create word with that name (in ANS Forth)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-09-11 10:51 -0500
      Re: Given a string, create word with that name (in ANS Forth)? Alex Dowad <alexinbeijing@gmail.com> - 2016-09-11 09:49 -0700
      Re: Given a string, create word with that name (in ANS Forth)? Lars Brinkhoff <lars.spam@nocrew.org> - 2016-09-11 19:57 +0200
        Re: Given a string, create word with that name (in ANS Forth)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-09-12 02:43 -0500
      Re: Given a string, create word with that name (in ANS Forth)? Paul Rubin <no.email@nospam.invalid> - 2016-09-11 14:31 -0700
    Re: Given a string, create word with that name (in ANS Forth)? hughaguilar96@gmail.com - 2016-09-11 10:14 -0700
    Re: Given a string, create word with that name (in ANS Forth)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-12 07:46 +0000
      Re: Given a string, create word with that name (in ANS Forth)? Paul Rubin <no.email@nospam.invalid> - 2016-09-12 01:10 -0700
        Re: Given a string, create word with that name (in ANS Forth)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-12 09:01 +0000
          Re: Given a string, create word with that name (in ANS Forth)? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-12 14:02 +0200
            Re: Given a string, create word with that name (in ANS Forth)? "HAA" <someone@microsoft.com> - 2016-09-20 12:06 +1000
              Re: Given a string, create word with that name (in ANS Forth)? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-20 11:27 +0200
          Re: Given a string, create word with that name (in ANS Forth)? Paul Rubin <no.email@nospam.invalid> - 2016-09-12 13:02 -0700
            Re: Given a string, create word with that name (in ANS Forth)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-13 16:20 +0000
              Re: Given a string, create word with that name (in ANS Forth)? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-13 21:08 +0200
                Re: Given a string, create word with that name (in ANS Forth)? Paul Rubin <no.email@nospam.invalid> - 2016-09-13 17:30 -0700
                  Re: Given a string, create word with that name (in ANS Forth)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-14 07:11 +0000
                    Re: Given a string, create word with that name (in ANS Forth)? hughaguilar96@gmail.com - 2016-09-14 18:30 -0700
            Re: Given a string, create word with that name (in ANS Forth)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-09-15 02:46 -0500
            Re: Given a string, create word with that name (in ANS Forth)? "Elizabeth D. Rather" <erather@forth.com> - 2016-09-20 14:27 -0700
              Re: Given a string, create word with that name (in ANS Forth)? hughaguilar96@gmail.com - 2016-09-20 15:05 -0700
                Re: Given a string, create word with that name (in ANS Forth)? Melzzzzz <Melzzzzz@zzzzz.com> - 2016-09-20 22:19 +0000
              Re: Given a string, create word with that name (in ANS Forth)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-21 12:26 +0000
                Re: Given a string, create word with that name (in ANS Forth)? Coos Haak <htrofhc@gmail.com> - 2016-09-21 15:11 +0200
                  Re: Given a string, create word with that name (in ANS Forth)? mhx@iae.nl - 2016-09-21 10:06 -0700
                    Re: Given a string, create word with that name (in ANS Forth)? Coos Haak <htrofhc@gmail.com> - 2016-09-21 21:12 +0200
                Re: Given a string, create word with that name (in ANS Forth)? "Elizabeth D. Rather" <erather@forth.com> - 2016-09-21 12:06 -1000
                  Re: Given a string, create word with that name (in ANS Forth)? Paul Rubin <no.email@nospam.invalid> - 2016-09-21 15:40 -0700
                    Re: Given a string, create word with that name (in ANS Forth)? "HAA" <someone@microsoft.com> - 2016-09-22 13:04 +1000
                  Re: Given a string, create word with that name (in ANS Forth)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-22 07:40 +0000
                    Re: Given a string, create word with that name (in ANS Forth)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2016-09-22 15:46 +0100
                      Re: Given a string, create word with that name (in ANS Forth)? hughaguilar96@gmail.com - 2016-09-22 11:08 -0700
                      Re: Given a string, create word with that name (in ANS Forth)? Lars Brinkhoff <lars.spam@nocrew.org> - 2016-09-22 22:04 +0200
                        Re: Given a string, create word with that name (in ANS Forth)? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2016-09-23 10:21 +0100
                          Re: Given a string, create word with that name (in ANS Forth)? Lars Brinkhoff <lars.spam@nocrew.org> - 2016-09-23 12:06 +0200
                            Re: Given a string, create word with that name (in ANS Forth)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-09-23 10:44 -0500
                              Re: Given a string, create word with that name (in ANS Forth)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-23 16:26 +0000
                                Re: Given a string, create word with that name (in ANS Forth)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-09-24 03:46 -0500
                                  Re: Given a string, create word with that name (in ANS Forth)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-24 10:13 +0000
                                    Re: Given a string, create word with that name (in ANS Forth)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-09-24 10:34 -0500
                                      Re: Given a string, create word with that name (in ANS Forth)? Lars Brinkhoff <lars.spam@nocrew.org> - 2016-09-24 20:19 +0200
                                        Re: Given a string, create word with that name (in ANS Forth)? "Elizabeth D. Rather" <erather@forth.com> - 2016-09-24 09:47 -1000
                                          Re: Given a string, create word with that name (in ANS Forth)? Paul Rubin <no.email@nospam.invalid> - 2016-09-24 14:29 -0700
                                            Re: Given a string, create word with that name (in ANS Forth)? "Elizabeth D. Rather" <erather@forth.com> - 2016-09-24 13:00 -1000
                                              Re: Given a string, create word with that name (in ANS Forth)? Paul Rubin <no.email@nospam.invalid> - 2016-09-24 16:19 -0700
                                              Re: Given a string, create word with that name (in ANS Forth)? jim.brakefield@ieee.org - 2016-09-24 19:02 -0700
                                                Re: Given a string, create word with that name (in ANS Forth)? "Elizabeth D. Rather" <erather@forth.com> - 2016-09-24 21:23 -1000
                                                  Re: Given a string, create word with that name (in ANS Forth)? hughaguilar96@gmail.com - 2016-09-25 19:08 -0700
                                                    Re: Given a string, create word with that name (in ANS Forth)? jim.brakefield@ieee.org - 2016-09-25 19:53 -0700
                                                      Re: Given a string, create word with that name (in ANS Forth)? hughaguilar96@gmail.com - 2016-09-25 20:00 -0700
                                              Re: Given a string, create word with that name (in ANS Forth)? hughaguilar96@gmail.com - 2016-09-25 17:40 -0700
                                            Re: Given a string, create word with that name (in ANS Forth)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-09-25 01:42 -0500
                                              Re: Given a string, create word with that name (in ANS Forth)? Paul Rubin <no.email@nospam.invalid> - 2016-09-24 23:45 -0700
                                                Re: Given a string, create word with that name (in ANS Forth)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-09-25 02:22 -0500
                                                  Re: Given a string, create word with that name (in ANS Forth)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-26 15:31 +0000
                                                    Re: Given a string, create word with that name (in ANS Forth)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-09-26 10:42 -0500
                                                      Re: Given a string, create word with that name (in ANS Forth)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-27 15:57 +0000
                                                        Re: Given a string, create word with that name (in ANS Forth)? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-27 19:11 +0200
                                                Re: Given a string, create word with that name (in ANS Forth)? "Elizabeth D. Rather" <erather@forth.com> - 2016-09-24 21:28 -1000
                                            Re: Given a string, create word with that name (in ANS Forth)? hughaguilar96@gmail.com - 2016-09-25 18:55 -0700
                                          Re: Given a string, create word with that name (in ANS Forth)? Lars Brinkhoff <lars.spam@nocrew.org> - 2016-09-25 09:35 +0200
                                          Re: Given a string, create word with that name (in ANS Forth)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-26 15:38 +0000
                                            Re: Given a string, create word with that name (in ANS Forth)? hughaguilar96@gmail.com - 2016-09-26 12:36 -0700
                                      Re: Given a string, create word with that name (in ANS Forth)? Lars Brinkhoff <lars.spam@nocrew.org> - 2016-09-24 20:26 +0200
                                      Re: Given a string, create word with that name (in ANS Forth)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-25 15:22 +0000
                                        Re: Given a string, create word with that name (in ANS Forth)? Paul Rubin <no.email@nospam.invalid> - 2016-09-25 10:44 -0700
                                          Re: Given a string, create word with that name (in ANS Forth)? Coos Haak <htrofhc@gmail.com> - 2016-09-25 19:55 +0200
                                            Re: Given a string, create word with that name (in ANS Forth)? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-25 20:15 +0200
                                              Re: Given a string, create word with that name (in ANS Forth)? Coos Haak <htrofhc@gmail.com> - 2016-09-25 20:26 +0200
                                            Re: Given a string, create word with that name (in ANS Forth)? Paul Rubin <no.email@nospam.invalid> - 2016-09-25 11:12 -0700
                                              Re: Given a string, create word with that name (in ANS Forth)? Julian Fondren <julian.fondren@gmail.com> - 2016-09-25 11:30 -0700
                                              Re: Given a string, create word with that name (in ANS Forth)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-26 14:51 +0000
                                                Re: Given a string, create word with that name (in ANS Forth)? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-27 14:16 +0200
                            Re: Given a string, create word with that name (in ANS Forth)? "Elizabeth D. Rather" <erather@forth.com> - 2016-09-23 07:52 -1000
                        Re: Given a string, create word with that name (in ANS Forth)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-09-23 10:36 -0500
      Re: Given a string, create word with that name (in ANS Forth)? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-12 13:55 +0200
        Re: Given a string, create word with that name (in ANS Forth)? Lars Brinkhoff <lars.spam@nocrew.org> - 2016-09-12 15:01 +0200
        Re: Given a string, create word with that name (in ANS Forth)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-12 17:29 +0000
          Re: Given a string, create word with that name (in ANS Forth)? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-12 21:02 +0200
            Re: Given a string, create word with that name (in ANS Forth)? Paul Rubin <no.email@nospam.invalid> - 2016-09-12 13:04 -0700
              Re: Given a string, create word with that name (in ANS Forth)? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-12 22:33 +0200
                Re: Given a string, create word with that name (in ANS Forth)? lawrencedo99@gmail.com - 2016-09-16 18:38 -0700
                  Re: Given a string, create word with that name (in ANS Forth)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-17 05:33 +0000
                    Re: Given a string, create word with that name (in ANS Forth)? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-09-17 01:40 -0500
                    Re: Given a string, create word with that name (in ANS Forth)? lawrencedo99@gmail.com - 2016-09-16 23:47 -0700
                      Re: Given a string, create word with that name (in ANS Forth)? Julian Fondren <julian.fondren@gmail.com> - 2016-09-17 00:08 -0700
                      Re: Given a string, create word with that name (in ANS Forth)? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-17 17:03 +0000
              Re: Given a string, create word with that name (in ANS Forth)? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-12 22:35 +0200
              Re: Given a string, create word with that name (in ANS Forth)? Jan Coombs <jenfhaomndgfwutc@murmic.plus.com> - 2016-09-17 08:16 +0100
    Re: Given a string, create word with that name (in ANS Forth)? Mark Wills <markwills1970@gmail.com> - 2016-09-12 02:49 -0700
      Re: Given a string, create word with that name (in ANS Forth)? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-12 14:04 +0200
      Re: Given a string, create word with that name (in ANS Forth)? Cecil Bayona <cbayona@cbayona.com> - 2016-09-12 09:34 -0500
        Re: Given a string, create word with that name (in ANS Forth)? Mark Wills <markwills1970@gmail.com> - 2016-09-12 08:10 -0700
          Re: Given a string, create word with that name (in ANS Forth)? Cecil Bayona <cbayona@cbayona.com> - 2016-09-12 12:02 -0500
    Re: Given a string, create word with that name (in ANS Forth)? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-12 14:08 +0200

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#51241

Anton Ertl <anton@mips.complang.tuwien.ac.at> wrote:
> Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>>Anton Ertl <anton@mips.complang.tuwien.ac.at> wrote:
>>> Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>>>>My take on it is that the dictionary is a very specific structure
>>>>which is optimized for the job it does.  It doesn't necessarily
>>>>provide O(1) access, for example.
>>> 
>>> So what?  
>>
>>That was obvious from the context.
>>
>>> There are no performance guarantees anywhere in the Forth
>>
>>That was my point.  That was obvious from the context.
> 
> Which context?

The context you deleted from the message to which I was replying.

>>> Why should I use a system-specific interface?
>>
>>If the O(1) performance of a hash table is essential to your design,
> 
> Where did you get the idea that it was essential?

Note the "if" in the statement above.  A hash table was mentioned, I
think.

>>then you'll have to use a hash table; the dictionary might be a linear
>>search.
> 
> If average-constant access performance is essential, there are several
> options:
> 
> 1) I can use the dictionary, and choose one of the Forth systems that
> provide average-constant access performance for that.

Of course.

> Just because there may be a few systems that do not provide the
> necessary performance yet, does not mean it is a good idea or even
> recommended to use a system-specific interfaces, because that would
> restrict usage of the program to that one system; then I would not
> even notice that other Forth systems provide average-constant access
> performance, maybe in a later version.

Of course.

> 2) If I want more performance portability, I can define the lookup
> table myself in Forth, or use a library, e.g., the ffl.  And in that
> context a system-specific interface makes even less sense.

Sure, but the system-specific interface *is* needed in the context
where strings with embedded spaces are used as keys.  (Having said
that, the strings can be encoded in some way, so the dictionary could
be used even then, but it would be inconvenient.)

> So you put up a straw man that does not even support your case.

The question which arose was to do with the usage of the dictionary as
a general-purpose lookup table for arbitrary strings.  The
disadvantage of the dictionary for that purpose is that its
performance varies widely and that it doesn't accept arbitrary
strings.  Some systems might well have fast dictionary lookup, and
they might support arbitrary strings as an extension.  In practice I
suspect that the prorammer will know which system they are writing for
and do whatever works best for that system.

Andrew.

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#51244

Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
> A hash table was mentioned, I think.

I mentioned "hash table", but now I'm sorry I did.  I could have written
"mapping" or "associative array" or something.

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#51246

On 9/24/16 8:19 AM, Lars Brinkhoff wrote:
> Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>> A hash table was mentioned, I think.
>
> I mentioned "hash table", but now I'm sorry I did.  I could have written
> "mapping" or "associative array" or something.
>

The thing is, each of those application areas has its own needs. The 
dictionary is, itself, an application with certain needs, and 
complicating the dictionary to make a general-purpose facility will not 
benefit either Forth or any of those uses.

Cheers,
Elizabeth

-- 
==================================================
Elizabeth D. Rather   (US & Canada)   800-55-FORTH
FORTH Inc.                         +1 310.999.6784
5959 West Century Blvd. Suite 700
Los Angeles, CA 90045
http://www.forth.com

"Forth-based products and Services for real-time
applications since 1973."
==================================================

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#51250

"Elizabeth D. Rather" <erather@forth.com> writes:
>> "mapping" or "associative array" or something.
> The thing is, each of those application areas has its own needs. The
> dictionary is, itself, an application with certain needs, and
> complicating the dictionary to make a general-purpose facility will
> not benefit either Forth or any of those uses.

Associative tables have shown themselves to be a very useful datatype in
many other languages, and the implementation details are usually not
that important.  Forth uses one to implement dictionaries/wordlists, but
its interface is very restricted.  And if the application implements its
own, but that means there are now two different implementations in the
Forth running the app.

If a general purpose table had been available from the beginning, the
Forth dictionary would be able to use it, and the user app could use it
too.

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#51253

On 9/24/16 11:29 AM, Paul Rubin wrote:
> "Elizabeth D. Rather" <erather@forth.com> writes:
>>> "mapping" or "associative array" or something.
>> The thing is, each of those application areas has its own needs. The
>> dictionary is, itself, an application with certain needs, and
>> complicating the dictionary to make a general-purpose facility will
>> not benefit either Forth or any of those uses.
>
> Associative tables have shown themselves to be a very useful datatype in
> many other languages, and the implementation details are usually not
> that important.  Forth uses one to implement dictionaries/wordlists, but
> its interface is very restricted.  And if the application implements its
> own, but that means there are now two different implementations in the
> Forth running the app.
>
> If a general purpose table had been available from the beginning, the
> Forth dictionary would be able to use it, and the user app could use it
> too.
>

Well, it's been a basic principal of Forth since before I met Chuck 
(1971) that it's preferable to solve specific problems optimally than to 
attempt to define generalized structures that might or might not be 
optimal for a specific case. The dictionary is one example of this 
principal at work.

You may not agree, and you're perfectly entitled to device a general 
purpose table and use it for your dictionary, but at this stage an 
attempt to force Forth into that mold is unlikely to be popular.

Cheers,
Elizabeth

-- 
==================================================
Elizabeth D. Rather   (US & Canada)   800-55-FORTH
FORTH Inc.                         +1 310.999.6784
5959 West Century Blvd. Suite 700
Los Angeles, CA 90045
http://www.forth.com

"Forth-based products and Services for real-time
applications since 1973."
==================================================

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#51254

"Elizabeth D. Rather" <erather@forth.com> writes:
> it's preferable to solve specific problems optimally than
> to attempt to define generalized structures that might or might not be
> optimal for a specific case.

If 3 similar problems arise in a program, is it more optimal to have 3
separate solutions that are almost but not quite all alike, or to have
one solution that handles all 3 problems?

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#51257

On Saturday, September 24, 2016 at 6:00:29 PM UTC-5, Elizabeth D. Rather wrote:
> On 9/24/16 11:29 AM, Paul Rubin wrote:
> > "Elizabeth D. Rather" <erather@forth.com> writes:
> >>> "mapping" or "associative array" or something.
> >> The thing is, each of those application areas has its own needs. The
> >> dictionary is, itself, an application with certain needs, and
> >> complicating the dictionary to make a general-purpose facility will
> >> not benefit either Forth or any of those uses.
> >
> > Associative tables have shown themselves to be a very useful datatype in
> > many other languages, and the implementation details are usually not
> > that important.  Forth uses one to implement dictionaries/wordlists, but
> > its interface is very restricted.  And if the application implements its
> > own, but that means there are now two different implementations in the
> > Forth running the app.
> >
> > If a general purpose table had been available from the beginning, the
> > Forth dictionary would be able to use it, and the user app could use it
> > too.
> >
> 
> Well, it's been a basic principal of Forth since before I met Chuck 
> (1971) that it's preferable to solve specific problems optimally than to 
> attempt to define generalized structures that might or might not be 
> optimal for a specific case. The dictionary is one example of this 
> principal at work.
> 
> You may not agree, and you're perfectly entitled to device a general 
> purpose table and use it for your dictionary, but at this stage an 
> attempt to force Forth into that mold is unlikely to be popular.
> 
> Cheers,
> Elizabeth
> 
> -- 
> ==================================================
> Elizabeth D. Rather   (US & Canada)   800-55-FORTH
> FORTH Inc.                         +1 310.999.6784
> 5959 West Century Blvd. Suite 700
> Los Angeles, CA 90045
> http://www.forth.com
> 
> "Forth-based products and Services for real-time
> applications since 1973."
> ==================================================

]> it's preferable to solve specific problems optimally than to 
]> attempt to define generalized structures that might or might not be 
]> optimal for a specific case. The dictionary is one example of this 
]> principal at work

In much of my scientific/research programming, made the decision that if it was in a factor of two in time efficiency, that was good enough: my time versus the computer's time.  In this situation generalized solutions were
more easily verified and held out greater chance of reuse.

Many years later, the case of a interrupt handler for a Z80, needed to handle 24 distinct interrupts, each slightly different.  A single piece of code would not meet timing due to the time it took to stuff all the bit fields.  24 separate routines, each with all the bit fields pre-stuffed easily met timing.  Was using assembler, so wrote a large macro and called it 24 times.  If using Forth, would have had Forth generate the code for the 24 routines.

Am not sure what Chuck Moore considered optimal?
And why are the Forth dictionary text stings not compressed to save space?

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#51265

On 9/24/16 4:02 PM, jim.brakefield@ieee.org wrote:
> ]> it's preferable to solve specific problems optimally than to
> ]> attempt to define generalized structures that might or might not be
> ]> optimal for a specific case. The dictionary is one example of this
> ]> principal at work
>
> In much of my scientific/research programming, made the decision that if it was in a factor of two in time efficiency, that was good enough: my time versus the computer's time.  In this situation generalized solutions were
> more easily verified and held out greater chance of reuse.
>
> Many years later, the case of a interrupt handler for a Z80, needed to handle 24 distinct interrupts, each slightly different.  A single piece of code would not meet timing due to the time it took to stuff all the bit fields.  24 separate routines, each with all the bit fields pre-stuffed easily met timing.  Was using assembler, so wrote a large macro and called it 24 times.  If using Forth, would have had Forth generate the code for the 24 routines.

:-)

> Am not sure what Chuck Moore considered optimal?

No absolute answers, it depended on the particular situation what to 
optimize.

> And why are the Forth dictionary text stings not compressed to save space?

Interesting question. For many years Chuck's systems and those of FORTH, 
Inc. saved the count and first 3 characters of the name rather than the 
full name, to save space. This provided a level of uniqueness that was 
adequate most of the time. This persisted until Forth94, by which time 
memories were sufficient to hold whole names except in small embedded 
systems, which by that time were programmed with cross-compilers at 
FORTH, Inc. The standards require uniqueness for 32 characters.

Cheers,
Elizabeth

-- 
==================================================
Elizabeth D. Rather   (US & Canada)   800-55-FORTH
FORTH Inc.                         +1 310.999.6784
5959 West Century Blvd. Suite 700
Los Angeles, CA 90045
http://www.forth.com

"Forth-based products and Services for real-time
applications since 1973."
==================================================

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#51306

On Sunday, September 25, 2016 at 12:23:46 AM UTC-7, Elizabeth D. Rather wrote:
> On 9/24/16 4:02 PM, jim.brakefield@ieee.org wrote:
> > And why are the Forth dictionary text stings not compressed to save space?
> 
> Interesting question. For many years Chuck's systems and those of FORTH, 
> Inc. saved the count and first 3 characters of the name rather than the 
> full name, to save space. This provided a level of uniqueness that was 
> adequate most of the time. This persisted until Forth94, by which time 
> memories were sufficient to hold whole names except in small embedded 
> systems, which by that time were programmed with cross-compilers at 
> FORTH, Inc. The standards require uniqueness for 32 characters.

That compression system of saving the count and the first 3 characters was only used at Forth Inc.. It was not adequate; there were a lot of clashes! Elizabeth Rather is projecting her own incompetance on to the entire Forth community --- she says that this goofy system, which was used only at Forth Inc., "persisted until Forth94" --- the implication is that the entire Forth community was unable to do anything that made sense until ANS-Forth came out in 1994.

Anyway, I'm not aware of any Forth system that used data-compression on the 65c02 and Z80 systems --- this was due to those processors being too slow to support data-compression --- later on the MS-DOS machines came out, and they had enough memory that data-compression was not needed.

UR/Forth stored the dictionary headers in a 64KB segment accessed with ES. I actually did run out of memory in the dictionary segment though --- this was in my 65c02 cross-compile --- this was because I was using the dictionary as an association to hold line-numbers for the symbolic-debugger to use.

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#51308

On Sunday, September 25, 2016 at 9:08:03 PM UTC-5, hughag...@gmail.com wrote:
> On Sunday, September 25, 2016 at 12:23:46 AM UTC-7, Elizabeth D. Rather wrote:
> > On 9/24/16 4:02 PM, jim.brakefield@ieee.org wrote:
> > > And why are the Forth dictionary text stings not compressed to save space?
> > 
> > Interesting question. For many years Chuck's systems and those of FORTH, 
> > Inc. saved the count and first 3 characters of the name rather than the 
> > full name, to save space. This provided a level of uniqueness that was 
> > adequate most of the time. This persisted until Forth94, by which time 
> > memories were sufficient to hold whole names except in small embedded 
> > systems, which by that time were programmed with cross-compilers at 
> > FORTH, Inc. The standards require uniqueness for 32 characters.
> 
> That compression system of saving the count and the first 3 characters was only used at Forth Inc.. It was not adequate; there were a lot of clashes! Elizabeth Rather is projecting her own incompetance on to the entire Forth community --- she says that this goofy system, which was used only at Forth Inc., "persisted until Forth94" --- the implication is that the entire Forth community was unable to do anything that made sense until ANS-Forth came out in 1994.
> 
> Anyway, I'm not aware of any Forth system that used data-compression on the 65c02 and Z80 systems --- this was due to those processors being too slow to support data-compression --- later on the MS-DOS machines came out, and they had enough memory that data-compression was not needed.
> 
> UR/Forth stored the dictionary headers in a 64KB segment accessed with ES. I actually did run out of memory in the dictionary segment though --- this was in my 65c02 cross-compile --- this was because I was using the dictionary as an association to hold line-numbers for the symbolic-debugger to use.

]>due to those processors (65c02 & Z80) being too slow to support data-compression

??
There are plenty of adhoc compression schemes that will save 20-30% over 8-bit ASCII, and that are reasonably fast.

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#51309

On Sunday, September 25, 2016 at 7:53:15 PM UTC-7, jim.bra...@ieee.org wrote:
> On Sunday, September 25, 2016 at 9:08:03 PM UTC-5, hughag...@gmail.com wrote:
> ]>due to those processors (65c02 & Z80) being too slow to support data-compression
> 
> ??
> There are plenty of adhoc compression schemes that will save 20-30% over 8-bit ASCII, and that are reasonably fast.

Maybe so --- I'm not an expert on data-compression --- I don't really know what is available.

The only data-compression algorithm I'm familiar with is Huffman Encoding --- I doubt that it would have been fast enough on those old processors.

Anyway, it is a moot point now because memory is no longer an issue.

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#51300

On Saturday, September 24, 2016 at 4:00:29 PM UTC-7, Elizabeth D. Rather wrote:
> Well, it's been a basic principal of Forth since before I met Chuck 
> (1971) that it's preferable to solve specific problems optimally than to 
> attempt to define generalized structures that might or might not be 
> optimal for a specific case. 

This is a great quote!

I think this really shows who Elizabeth Rather is entirely informed about computer-science by her experience as a COBOL programmer in the 1970s.

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#51262

Paul Rubin <no.email@nospam.invalid> wrote:

> If a general purpose table had been available from the beginning, the
> Forth dictionary would be able to use it, and the user app could use it
> too.

Perhaps so, but the system might not then have fit in the tiny space
available on small computers.  Every byte was valuable, and every byte
occupied by the Forth system was a byte that couldn't be used by the
application programmer.

Andrew.

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#51263

Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
> Perhaps so, but the system might not then have fit in the tiny space
> available on small computers.  Every byte was valuable, and every byte
> occupied by the Forth system was a byte that couldn't be used by the
> application programmer.

The really tiny systems might not have supported word lists, which is
about where generality starts making sense.  But, as someone mentioned,
Forth dictionary implementations generally had the general interfaces as
internal factors even if they weren't exposed to the user.  So it starts
to sound like burying a tool.

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#51264

Paul Rubin <no.email@nospam.invalid> wrote:
> Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>> Perhaps so, but the system might not then have fit in the tiny space
>> available on small computers.  Every byte was valuable, and every byte
>> occupied by the Forth system was a byte that couldn't be used by the
>> application programmer.
> 
> The really tiny systems might not have supported word lists, which is
> about where generality starts making sense.

I'm sure they all had vocabularies.  They at least had to have EDITOR
and ASSEMBLER.

> But, as someone mentioned, Forth dictionary implementations
> generally had the general interfaces as internal factors even if
> they weren't exposed to the user.

Not always.  Some small systems I know about have very tightly-
integrated interpreter and compiler, for example.  WORD copies a name
from the input stream to a small offset from HERE, so CREATE has only
to fill in a link field and a code field and it's done.  It's a tiny
simplification, but all those tiny simplifications add up.

Andrew.

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#51334

Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>Some small systems I know about have very tightly-
>integrated interpreter and compiler, for example.  WORD copies a name
>from the input stream to a small offset from HERE, so CREATE has only
>to fill in a link field and a code field and it's done.  It's a tiny
>simplification, but all those tiny simplifications add up.

On the contrary, it's a complication.  Instead of copying the name
only when defining a new word, this scheme always copies the name; and
in order to make use of it, you have to have the name field first in a
word, and the link field afterwards, leading to the complication and
slowness of TRAVERSE in fig-Forth (the option of having either full
names or shortened names also played a role in that complication).
You can get rid of all these complications by using PARSE-NAME instead
of WORD and copying the name on header definition.

- anton
-- 
M. Anton Ertl  http://www.complang.tuwien.ac.at/anton/home.html
comp.lang.forth FAQs: http://www.complang.tuwien.ac.at/forth/faq/toc.html
     New standard: http://www.forth200x.org/forth200x.html
   EuroForth 2016: http://www.euroforth.org/ef16/

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#51336

Anton Ertl <anton@mips.complang.tuwien.ac.at> wrote:
> Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>>Some small systems I know about have very tightly-
>>integrated interpreter and compiler, for example.  WORD copies a name
>>from the input stream to a small offset from HERE, so CREATE has only
>>to fill in a link field and a code field and it's done.  It's a tiny
>>simplification, but all those tiny simplifications add up.
> 
> On the contrary, it's a complication.  Instead of copying the name
> only when defining a new word, this scheme always copies the name;
> and in order to make use of it, you have to have the name field
> first in a word, and the link field afterwards, leading to the
> complication and slowness of TRAVERSE in fig-Forth (the option of
> having either full names or shortened names also played a role in
> that complication).

No you don't.  You can have the link field first.

Andrew.

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#51392

Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>Anton Ertl <anton@mips.complang.tuwien.ac.at> wrote:
>> Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>>>Some small systems I know about have very tightly-
>>>integrated interpreter and compiler, for example.  WORD copies a name
>>>from the input stream to a small offset from HERE, so CREATE has only
>>>to fill in a link field and a code field and it's done.  It's a tiny
>>>simplification, but all those tiny simplifications add up.
>> 
>> On the contrary, it's a complication.  Instead of copying the name
>> only when defining a new word, this scheme always copies the name;
>> and in order to make use of it, you have to have the name field
>> first in a word, and the link field afterwards, leading to the
>> complication and slowness of TRAVERSE in fig-Forth (the option of
>> having either full names or shortened names also played a role in
>> that complication).
>
>No you don't.  You can have the link field first.

Judging from your "small offset from HERE" phrase above, I guess that
you are implying that they could have had the name, say 2 bytes after
HERE, and put the link field at HERE.

However, an offset<>0 is contrary to established Forth practice to
this day (in Gforth, SwiftForth, and VFX WORD puts the string HERE,
not elsewhere).  And that was certainly more important for fig-Forth,
because in fig-Forth (and probably other Forth systems of the day)
WORD has the stack effect ( c -- ), and a typical phrase for using
WORD is

bl word here count ...

So if they did not put the string at HERE, the programs would not
work.

Looking at the dump of a definition, I find that SwiftForth does
indeed have the name where WORD puts it (I don't know if it uses WORD
for that, though), VFX puts the name elsewhere (6 bytes further in my
experiment).  Gforth (which uses PARSE-NAME anyway) uses a count cell
and puts the name 16 bytes after the old here in 0.7.0, and (for my
experiment) 13 byes after the old name, followed by the count cell in
the current development version.

I also looked WORD up in "All about Forth", and the two
implementations given in Forth (fig-Forth and F83) both first scanned
the whole string, and then copied it; so it's not as if the copying
came for free.

Overall, the copying of the string by WORD is just a bad idea, that
led to complications.  It may have been not so bad in the original
system, but it's definitely not an example of good design.

- anton
-- 
M. Anton Ertl  http://www.complang.tuwien.ac.at/anton/home.html
comp.lang.forth FAQs: http://www.complang.tuwien.ac.at/forth/faq/toc.html
     New standard: http://www.forth200x.org/forth200x.html
   EuroForth 2016: http://www.euroforth.org/ef16/

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#51393

In article <2016Sep27.175711@mips.complang.tuwien.ac.at>,
Anton Ertl <anton@mips.complang.tuwien.ac.at> wrote:
>
>Overall, the copying of the string by WORD is just a bad idea, that
>led to complications.  It may have been not so bad in the original
>system, but it's definitely not an example of good design.

With PARSE and PARSE-NAME we can make WORD obsolescent.
WORD is not needed in a kernel any more.
In ciforth it is made a loadable extension.

>
>- anton

Groetjes Albert
-- 
Albert van der Horst, UTRECHT,THE NETHERLANDS
Economic growth -- being exponential -- ultimately falters.
albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst

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#51266

On 9/24/16 8:45 PM, Paul Rubin wrote:
> Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>> Perhaps so, but the system might not then have fit in the tiny space
>> available on small computers.  Every byte was valuable, and every byte
>> occupied by the Forth system was a byte that couldn't be used by the
>> application programmer.
>
> The really tiny systems might not have supported word lists, which is
> about where generality starts making sense.  But, as someone mentioned,
> Forth dictionary implementations generally had the general interfaces as
> internal factors even if they weren't exposed to the user.  So it starts
> to sound like burying a tool.

Word lists (aka vocabularies) were first used in 1972, on a computer 
with 64K bytes of memory. Word lists are not memory hogs, although names 
were stored as count+first 3 chars. And, in Chuck's (and FORTH, Inc.) 
systems, these factors were always exposed. Chuck never buried anything.

Cheers,
Elizabeth

-- 
==================================================
Elizabeth D. Rather   (US & Canada)   800-55-FORTH
FORTH Inc.                         +1 310.999.6784
5959 West Century Blvd. Suite 700
Los Angeles, CA 90045
http://www.forth.com

"Forth-based products and Services for real-time
applications since 1973."
==================================================

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