Unquestionably, sentences producing non-noun are OK as long as they
don't end a T-block or a verb.
What I was proposing in (b) was that
v =: 3 : 0
...
5 + undefname
)
would be caught before exiting the verb, so that in debug you would
point to the bad sentence rather than the calling verb.
In contrast,
v =: 3 : 0
...
5 + undefname
if. 0 do. end.
)
would not be caught.
Henry Rich
On 5/31/2016 11:38 AM, bill lam wrote:
As the current behavior permit non-noun as the execution result
of a sentence in an explicit verb definition, so I prefer leave
as is (for B block).
It the verb returns a non-noun, it will raise a syntax error
in current J behavior although "non-noun result" error message
would be easier to be understood by new comers.
In contrast, the context of T block expected a noun, I prefer it
to be caught at the crime scene.
Just for clarification, non-noun result in the middle of T block
is fine.
t1=: 3 : 0
if.
1
+
2
do. 3 else. 4 end.
)
Вт, 31 май 2016, Henry Rich написал(а):
There are two different problems to consider.
1. A non-noun result at the end of a T block should be detected as an error
on the do., and should trap or go to catch. like any other error. Both of
your examples come under this heading. I will fix this.
2. A non-noun result at the end of a B block is different, because there
more sentences may be executed:
if. 1 do.
+
end.
if. 0: SomeComplicatedVerb y do.
5
end.
return.
The + is going to cause an error, but not until after the later T block,
including SomeComplicatedVerb, has been executed.
I can think of solutions:
a. leave as is
b. if the non-noun sentence is the last sentence executed before leaving the
verb, trap on it; otherwise continue as now
c. always go back and trap on the non-noun sentence when it is discovered
that it is generating the erroneous return value, even though other later
sentences may have executed and completely changed the program state
What solution is best?
Henry
On 5/28/2016 10:23 AM, bill lam wrote:
Sorry I had not included an example, it is about debug
suspension stack.
t1=: 3 : 0
1
t2''
4
)
t2=: 3 : 0
1
2
3
if. 0-: notexist_base_ do. end.
4
5
6
)
dbr 1
t1''
|control error: t2
|t2[3]
NB. this seemed ok, but
dbstack''
+----+--+--+--+----+------+----+
|name|en|ln|nc|args|locals|susp|
+----+--+--+--+----+------+----+
|t1 |23|1 |3 |++ |+-++ |* |
| | | | ||| ||y|| | |
| | | | |++ |+-++ | |
+----+--+--+--+----+------+----+
dbctx''
@@ t1[1] *v @@ /home/bill/a1.ijs
3 : 0
[0] 1
[1] t2''
[2] 4
NB. the top of stack (13!:13) is not t2.
Сб, 28 май 2016, Henry Rich написал(а):
I can reproduce the problem, which seems to be that a T block that has a
non-noun result doesn't go to the catch.
I don't understand your second part:
Also control error will can only be reported after exiting the
explicit verb, not the lines of control block.
Can you give an example of that?
I will work on this right after we get all the current branches merged together.
Henry Rich
On 5/27/2016 9:32 PM, bill lam wrote:
The handling of control error I had report many years ago,
http://www.jsoftware.com/pipermail/beta/2006-August/001776.html
Also control error will can only be reported after exiting the
explicit verb, not the lines of control block.
But Roger said it was the intended behavior. Can you take a look?
Вт, 17 май 2016, Henry Rich написал(а):
The J Engine is being worked on again. The people working on it are not
experts on it yet, but we have fixed quite a few of the long-standing bugs
and have plans for improvements.
There have long been Wiki pages for reporting bugs, pointed to by
http://code.jsoftware.com/wiki/System/Interpreter/Bugs
especially
http://code.jsoftware.com/wiki/System/Interpreter/Bugs/Crashes
and
http://code.jsoftware.com/wiki/System/Interpreter/Bugs/Errors
Quite a few of these have been fixed. If you have other bugs that are not
listed on those pages, please add an entry for them! The recent report of
trouble with
+.~1 2 1j_. 3
would be a model candidate.
Add an entry for your problem, and it'll get fixed.
Henry Rich
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