rabin (05/10/83)
contact 'fig-forth' in mountain view, california. ask them about the 'forth dimensions'. The publications will provide you with more examples then you'll ever need or want. Joining the 'fig' ( forth interest group ) costs 15 bucks a year.
rasp (05/11/83)
ValFORTH, then you are faced with a mild but basic
incompatibility problem. Anybody out there using figFORTH
or its derivatives should take heed, also.
In Brodie's book he creates variables by saying:
VARIABLE <variable name>
I believe that it automatically provides an initial value of
zero. In figFORTH, however, the variable takes its initial
value from the stack. Thus the declaration would be:
<initial value> VARIABLE <variable name>
A much nastier incompatibility between Brodie FORTH and
figFORTH is their treatments of the tick (') function.
Brodie's tick produces the code field address (CFA)
directly; therefore, it is possible to EXECUTE a 'ed name:
' VLIST EXECUTE
is exactly equivalent to typing VLIST. In figFORTH,
however, the tick function returns the PFA from which it is
possible to calculate the CFA by either subtracting 2 or
saying CFA. In figFORTH the sentence should read:
' VLIST CFA EXECUTE
or:
' VLIST 2 - EXECUTE
Failure to include the CFA or 2 - will result in a crash.
I don't know of any other major inconsistencies between the
two versions. That latter one is mean enough in that it
prevents you from sitting down at your computer and typing
in examples from the book.
For those of you that are into FORTH, here is a warning:
EVERY VERSION OF FORTH FOR THE ATARI THAT I HAVE
CHECKED SO FAR HAS A BUG IN IT THAT WILL CAUSE ABOUT
.4% OF ALL DEFINITIONS TO CRASH.
The explanation is involved, so I won't go into it on the
net unless there is considerable interest. If you care,
please write to me.
I hope you find these comments of interest.
Ron Perloff Burroughs ASG
16464 Via Esprillo San Diego,
CA 92128 619-451-4519
---!bmcg!rasp
9
9rasp (05/11/83)
I'm sorry that the first version of this article got smashed.
Here is what it should say:
If you are reading Leo Brodie's book, Starting FORTH, and
ValFORTH, then you are faced with a mild but basic
incompatibility problem. Anybody out there using figFORTH
or its derivatives should take heed, also.
In Brodie's book he creates variables by saying:
VARIABLE <variable name>
I believe that it automatically provides an initial value of
zero. In figFORTH, however, the variable takes its initial
value from the stack. Thus the declaration would be:
<initial value> VARIABLE <variable name>
A much nastier incompatibility between Brodie FORTH and
figFORTH is their treatments of the tick (') function.
Brodie's tick produces the code field address (CFA)
directly; therefore, it is possible to EXECUTE a 'ed name:
' VLIST EXECUTE
is exactly equivalent to typing VLIST. In figFORTH,
however, the tick function returns the PFA from which it is
possible to calculate the CFA by either subtracting 2 or
saying CFA. In figFORTH the sentence should read:
' VLIST CFA EXECUTE
or:
' VLIST 2 - EXECUTE
Failure to include the CFA or 2 - will result in a crash.
I don't know of any other major inconsistencies between the
two versions. That latter one is mean enough in that it
prevents you from sitting down at your computer and typing
in examples from the book.
For those of you that are into FORTH, here is a warning:
EVERY VERSION OF FORTH FOR THE ATARI THAT I HAVE
CHECKED SO FAR HAS A BUG IN IT THAT WILL CAUSE ABOUT
.4% OF ALL DEFINITIONS TO CRASH.
The explanation is involved, so I won't go into it on the
net unless there is considerable interest. If you care,
please write to me.
I hope you find these comments of interest.
Ron Perloff Burroughs ASG
16464 Via Esprillo San Diego,
CA 92128 619-451-4519
---!bmcg!rasp
9
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