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Re: How does the input stream traditionally work?

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On 16/03/2026 7:21 am, Paul Rubin wrote:
> dxf <dxforth@gmail.com> writes:
>> DX-Forth uses a 256 byte return stack.  The consequence of that is only
>> about 6 files can be included before it runs out.  
> 
> If you mean 6 levels of nesting, that seems sufficient for a small
> system.  It's around 20 return stack cells for each level.  Is that for
> a blocks system, or do you have files?  

Blocks are mapped onto OS files.  DX-Forth maintains a 'file descriptor
block' in memory of which there are 6.  A flag in the FDB determines
whether it's a block file, text file or unused.  Loading works on the
principle of a 'current file' whose pointer is saved/restored during
nesting.

> I guess it's reasonable to set
> aside a chunk of dictionary or block space to use as an explicit stack,
> if you want to remember filenames.

A field in the file descriptor block holds the filename.
 
> Do you use RPICK or anything like that, to get at the data for the
> current level?  

Not sure what you mean, but no, I use nothing fancy.

> I still don't understand the issue with using the data stack.  Maybe I
> haven't thought about it enough.

It would prevent nested files from passing data on the stack.

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Thread

How does the input stream traditionally work? Paul Rubin <no.email@nospam.invalid> - 2026-03-13 15:10 -0700
  Re: How does the input stream traditionally work? peter <peter.noreply@tin.it> - 2026-03-14 10:12 +0100
    Re: How does the input stream traditionally work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-03-14 15:09 +0000
      Re: How does the input stream traditionally work? peter <peter.noreply@tin.it> - 2026-03-14 23:30 +0100
        Re: How does the input stream traditionally work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-03-15 14:02 +0000
          Re: How does the input stream traditionally work? albert@spenarnc.xs4all.nl - 2026-03-15 19:25 +0100
  Re: How does the input stream traditionally work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-03-14 11:26 +0000
    Re: How does the input stream traditionally work? Paul Rubin <no.email@nospam.invalid> - 2026-03-14 23:34 -0700
      Re: How does the input stream traditionally work? dxf <dxforth@gmail.com> - 2026-03-15 18:26 +1100
        Re: How does the input stream traditionally work? Paul Rubin <no.email@nospam.invalid> - 2026-03-15 13:21 -0700
          Re: How does the input stream traditionally work? dxf <dxforth@gmail.com> - 2026-03-16 10:46 +1100
            Re: How does the input stream traditionally work? Paul Rubin <no.email@nospam.invalid> - 2026-03-15 18:09 -0700
              Re: How does the input stream traditionally work? dxf <dxforth@gmail.com> - 2026-03-16 13:13 +1100
                Re: How does the input stream traditionally work? Paul Rubin <no.email@nospam.invalid> - 2026-03-16 15:14 -0700
                Re: How does the input stream traditionally work? dxf <dxforth@gmail.com> - 2026-03-17 10:37 +1100
                Re: How does the input stream traditionally work? Paul Rubin <no.email@nospam.invalid> - 2026-03-16 17:27 -0700
                Re: How does the input stream traditionally work? dxf <dxforth@gmail.com> - 2026-03-17 12:48 +1100
                Re: How does the input stream traditionally work? albert@spenarnc.xs4all.nl - 2026-03-17 11:16 +0100
                Re: How does the input stream traditionally work? Gerry Jackson <do-not-use@swldwa.uk> - 2026-03-17 11:27 +0000
            Re: How does the input stream traditionally work? dxf <dxforth@gmail.com> - 2026-04-21 18:40 +1000
              Re: How does the input stream traditionally work? albert@spenarnc.xs4all.nl - 2026-04-21 12:39 +0200
              Re: How does the input stream traditionally work? Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-21 19:47 +0200
      Re: How does the input stream traditionally work? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-03-15 16:29 +0000
        Re: How does the input stream traditionally work? albert@spenarnc.xs4all.nl - 2026-03-15 19:48 +0100
  Re: How does the input stream traditionally work? albert@spenarnc.xs4all.nl - 2026-03-14 15:33 +0100

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