Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.forth > #30620

Re: A slightly longer mini-oof2.fs example.

Show all headers | View raw

Andrew Haley wrote:
> Gosh, just me, really?  The only thing I was skeptical about was
> having THIS as a hidden argument passed to all routines, even colon
> definitions.  I don't think doing that is a good idea: Forth should
> pass arguments, including THIS, on the stack.  As far as I'm aware,
> most (non-Forth) OOP languages do that.  So, I have no objection to
> the idea of a current object, I just think it should be passed in the
> normal way.

"the normal way" is more pragmatic in Forth.  First of all, we don't have 
just *the* stack.  We have a data stack, a floating point stack, and a 
return stack; Gforth has a separate locals stack.  A number of string 
packages offer a string stack, we have a vocabulary stack, there's a 
recognizer stack in Gforth.  Having more than one stack is natural in Forth.

As it quickly turned out with packages like mini-oof.fs, having the object 
on the data stack is too much of an obstacle.  Mini-OOF is barely usable, 
especially for accessing the instance variables.  So you will soon have a 
current object.  Now what?  Use it only for instance variables?  This 
results in inconsistent use: instance variables are relative to the current 
object, methods take it from the stack.  Inconsistent interfaces clutter the 
mind, and therefore should be avoided.

Result: Use a stack (shared with the return stack) for the current object, 
with the top of stack in a user variable or register, passed implicitely to 
other methods.

BTW: Mini-OOF2 has a "plugin system" for how methods and instance variables 
work, so you can make them whatever you want (including explicit object 
passing for methods and implicit for instance variables).  One of the ways 
to plug into that system is to have specific "current objects" for different 
classes.  E.g. the IO vectors in Gforth use that: There's a current output 
object and a current input object.  KEY and EMIT call through that objects, 
they are really just methods.

It wouldn't work if these methods would require a current object on the 
stack.

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
http://bernd-paysan.de/

Back to comp.lang.forth | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

A slightly longer mini-oof2.fs example. Julian Fondren <ayrnieu@gmail.com> - 2014-05-22 19:29 -0700
  Re: A slightly longer mini-oof2.fs example. albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-05-23 11:22 +0000
    Re: A slightly longer mini-oof2.fs example. Julian Fondren <ayrnieu@gmail.com> - 2014-05-23 09:38 -0700
  Re: A slightly longer mini-oof2.fs example. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-05-23 12:11 +0000
    Re: A slightly longer mini-oof2.fs example. Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-05-23 10:26 -0500
      Re: A slightly longer mini-oof2.fs example. Bernd Paysan <bernd.paysan@gmx.de> - 2014-05-23 19:59 +0200
        Re: A slightly longer mini-oof2.fs example. Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-05-24 04:23 -0500
        Re: A slightly longer mini-oof2.fs example. Hans Bezemer <the.beez.speaks@gmail.com> - 2014-05-24 15:47 +0200
          Re: A slightly longer mini-oof2.fs example. Julian Fondren <ayrnieu@gmail.com> - 2014-05-26 12:46 -0700
        Re: A slightly longer mini-oof2.fs example. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-05-24 15:35 +0000
          Re: A slightly longer mini-oof2.fs example. Alexander Skobelev <al.skobelev@gmail.com> - 2014-05-24 20:45 +0400
          Re: A slightly longer mini-oof2.fs example. Bernd Paysan <bernd.paysan@gmx.de> - 2014-05-24 21:46 +0200
            Re: A slightly longer mini-oof2.fs example. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-05-25 15:03 +0000
              Re: A slightly longer mini-oof2.fs example. Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-05-25 15:16 -0500
              Re: A slightly longer mini-oof2.fs example. Bernd Paysan <bernd.paysan@gmx.de> - 2014-05-26 00:47 +0200
          Re: A slightly longer mini-oof2.fs example. Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-05-25 18:55 -0500
            Re: A slightly longer mini-oof2.fs example. albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-05-26 11:44 +0000
              Re: A slightly longer mini-oof2.fs example. Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-05-27 05:25 -0500
                Re: A slightly longer mini-oof2.fs example. albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-05-27 11:56 +0000
            Re: A slightly longer mini-oof2.fs example. Julian Fondren <ayrnieu@gmail.com> - 2014-05-26 12:18 -0700
              Re: A slightly longer mini-oof2.fs example. Paul Rubin <no.email@nospam.invalid> - 2014-05-26 12:46 -0700
                Re: A slightly longer mini-oof2.fs example. Julian Fondren <ayrnieu@gmail.com> - 2014-05-26 13:43 -0700
              Re: A slightly longer mini-oof2.fs example. Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-05-27 05:28 -0500
    Re: A slightly longer mini-oof2.fs example. Julian Fondren <ayrnieu@gmail.com> - 2014-05-23 09:39 -0700
      Re: A slightly longer mini-oof2.fs example. mhx@iae.nl - 2014-05-23 10:29 -0700
      Re: A slightly longer mini-oof2.fs example. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-05-23 17:16 +0000
  Re: A slightly longer mini-oof2.fs example. andraszsoter@gmail.com - 2014-05-26 10:23 -0700
    Re: A slightly longer mini-oof2.fs example. Mark Wills <markwills1970@gmail.com> - 2014-05-27 02:09 -0700
      Re: A slightly longer mini-oof2.fs example. Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-05-27 06:07 -0500
      Re: A slightly longer mini-oof2.fs example. andraszsoter@gmail.com - 2014-05-28 10:17 -0700
    Re: A slightly longer mini-oof2.fs example. Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-05-27 05:39 -0500
      Re: A slightly longer mini-oof2.fs example. Mark Wills <markwills1970@gmail.com> - 2014-05-27 04:02 -0700
        Re: A slightly longer mini-oof2.fs example. Mark Wills <markwills1970@gmail.com> - 2014-05-27 04:04 -0700
        Re: A slightly longer mini-oof2.fs example. Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-05-27 06:19 -0500

csiph-web