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List with unexpected values!?
Posted: Tue Nov 24, 2009 10:19 pm
by xernobyl
Why is my
gennum function attaching it's return value
l? I've commented everything inside gennum, just left a return value.
Code: Select all
(loop for y below m do
(loop for x below n do
(when(zerop(coord x y table))
(print l)
(unless(setf v([b]gennum[/b] x y [b]l[/b] out))
(return-from alpha nil)))))
Re: List with unexpected values!?
Posted: Tue Nov 24, 2009 11:28 pm
by ramarren
xernobyl wrote:Why is my gennum function attaching it's return value l? I've commented everything inside gennum, just left a return value.
That code is very confusingly indented, and hence unreadable. Please use standard indentation rules. It is also apparently a fragment with missing context. Since, as it stands, it uses several identifiers as global variables, it is impossible to say anything about its behaviour. In any case, using the return value of SETF as a condition seems weird. And I don't even understand your question, "attaching its return value" to what?
Re: List with unexpected values!?
Posted: Wed Nov 25, 2009 6:08 pm
by xernobyl
Trying to simplify the problem...
This:
Code: Select all
(print l)
(loop for y below m do
(loop for x below n do
(when(zerop(coord x y table))
(setf v (gennum x y l out))
(put v x y out)
(push v l)))
(print v)
(print l))
Outputs:
Code: Select all
(1 8 2 9 6)
7
(7 8 2 0 9 0 6 NIL NIL NIL)
3
(3 0 1 NIL 2 0 NIL 7 6 NIL)
7
(7 NIL NIL NIL NIL 0 4 NIL 8 2)
Why is my list l getting values other than those in v (the nils and 0s)?
Why doesn't it result in this:
Code: Select all
(1 8 2 9 6)
7
(7 1 8 2 9 6)
3
(3 7 1 8 2 9 6)
7
(7 7 1 8 2 9 6)
???
Re: List with unexpected values!?
Posted: Thu Nov 26, 2009 2:32 am
by ramarren
xernobyl wrote:Trying to simplify the problem...
That code on my system results in:
Code: Select all
The variable L is unbound.
[Condition of type UNBOUND-VARIABLE]
on the very first line, and so is useless.
My guess would be that you are mutating constant literals somewhere inside those operators you didn't show the source for. Remember that QUOTE (abbreviated with quote symbol syntax) is not the same as LIST. Remember that you have to bind variables before setting them (that 'v' looks suspicious).