Hi Neil,
This sounds suspiciously like my University of Teeside ICA for this year?
Anyway, a few comments that might help hopefully (With a bit of luck,
they should be in italics!).
fun {Attack U V}
R
in
case U of XI#YI then
case V of XII#YII then
if U.1 == V.1 then % Horizontal line.
/you've already decomposed or 'split' U into XI and YI,
and V into XII and YII
so the line above should read
if XI == XII then true
and the line below should be
if YI == YII then true
/ true
elseif U.2 == V.2 then % Vertical line.
true
elseif ( XI - XII ) == ( YI - YII) then % Diagonal lines.
true
/i'm struggling a bit here to decide what exactly is
being checked in
the lines above and below here, but i would suggest
these two lines should be
elseif (XI-YI) == (XII-YII) then true
elseif (XI+YI) == (XII+YII) then true
you need to do both the + and - to test for diagonals in
each direction.
/// elseif ( XI - XII ) == ( YII - YI ) then
true
else
false
end
end
end
end
/All in all, I would suggest something like this might be a lot clearer
for you:
fun {Attack U V}
case U of XI#YI then
case V of XII#YII then
(XI==XII) orelse /% /(XI == XII) will equate to either true or false/
/ (YI==YII) orelse % ditto
((XI-YI)==(XII-YII)) orelse
((XI+YI)==(XII+YII)) else
false
end
end
end
Your {Threaten} function looks fine.
/
fun {Revise L}
case L of H|T then
if {Length L} == BoardSize then {Revise L}
else N = {Length L} in
{Threaten T H} then
{Revise H.1+1#H.2+1|T}
else H.1+1#H.2+1|T
end
end
end
I know this function does not work and if anyone could provide any
help as to why it does not work I'd appreciate it, I have neither a
mathematics nor engineering background so explanations may have to be
quite simplistic.
/I could go into a number of reasons why this won't work, one of which
is you're creating a local variable N which you need but you're not
using it.
You said the tutor gave you the {Revise} function, trust him, it works
perfectly as it is.
It is a case of using the function properly.
I would therefore stick with your original version:
/fun {Revise L}
case L of H|T then
if H == BoardSize then {Revise T} % Never gonna reach this point
/you WILL reach this point! This function should be being
called by another function
which is attempting to create a completed list of
un-threatened coords.
/ else N = {GetLengthOfList L} in % since H is X#X, boardsize is
an int.
/L at this point is a list of column numbers ie. integer
values, therefore H is also
going to be an integer. It is the {BuildList} function
which makes the list into a
X#X form.
/ if {Threaten {BuildList T} H+1#N} then {Revise H+1|T}
else H+1|T
end
end
else nil
end
end/
Hope this helps.
Also, if you have time , I think you'd get better marks if you make the
QTk part into just one window.
If you need any more help, post a question again.
For anyone that is trying to help you, they won't know that you have
been restricted to using certain functions.
It would be so much simpler to use Finite-domain programming as Torsten
suggested. I tried it that way to see
and it is soooo much simpler.
But.....good luck anyway!
Regards
/Mark Richardson
Final year degree student
University of Teeside
/
/
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