OF1275 Questions

[John R. Hogerhuis]

Hello,

I'm plodding my way through OF1275.

In section 3.2.2.3.1 reference is made to the Forth
words

DEFER
INSTANCE
BUFFER:

I couldn't find these in the DPANS94 spec... anyone
know what these are? I never did much with ANS Forth,
so I am not sure why I can't find these words in the
docs. Perhaps INSTANCE and BUFFER: are specific to OF?

I assume DEFER is for deferred definition/vectored
execution words.  Why isn't it in ANS spec?

Thanks,

-- John.

__________________________________________________
Do You Yahoo!?
LAUNCH - Your Yahoo! Music Experience
http://launch.yahoo.com
-
To unsubscribe: send mail to [e-mail]
with 'unsubscribe openbios' in the body of the message
http://www.freiburg.linux.de/OpenBIOS/ - free your system..

[Patrick Mauritz]

On Tue, May 21, 2002 at 09:52:27PM -0700, John R. Hogerhuis wrote:
> DEFER

think of it as a forward declaration.

defer foobar

creates a word foobar that displays a
message, sth like "tried execution of an uninitialized
defer word" which can be overwritten by

['] foobar ( the old name) to some-forth-word

if you run foobar after that, it does the same as
some-forth-word

cannot be used inside a colon definition
> INSTANCE

creates the next occurence of buffer, defer, value or
variable instance specific. that way it'll get reallocated 
each time an instance of that package is created

ex. from IEEE1275: ok 30 instance value new-name
> BUFFER:

creates a named buffer of a given size which returns the
address of the first byte on execution
ex. from IEEE1275:

100 buffer: new-name ( creates a buffer called new-name
                       which has 100 bytes)
55 new-name 20 + c!  ( writes 55 in new-name[20])
> I couldn't find these in the DPANS94 spec... anyone
> know what these are? I never did much with ANS Forth,
> so I am not sure why I can't find these words in the
> docs. Perhaps INSTANCE and BUFFER: are specific to OF?

OF uses a subset of ANS but extends it with own words - 
I think the same thing is achieved with different words
in ANS and OF at some places

hope I could help,
patrick mauritz

[Segher Boessenkool]

> OF uses a subset of ANS but extends it with own words -
> I think the same thing is achieved with different words
> in ANS and OF at some places

OF actually has a (slightly) different definition of some words
than ANS, has some extra "standard" Forth words that ANS has not,
and doesn't have some of the ANS required words.  Confused yet?

Cheers,

Segher

-
To unsubscribe: send mail to [e-mail]
with 'unsubscribe openbios' in the body of the message
http://www.freiburg.linux.de/OpenBIOS/ - free your system..