Operator not applicable error, help would be awsome

hello, me agian Bubblez101

I got an error that i never seen before. knowing what it actually means would be a great help.

This is the error:
Operator not applicable to this operand type

here is the code that the error highlighted on:

if not ch := LetterList then
showmessage('You have used that letter already, choose another letter!');
LetterList.add := ch+LetterList;

I have declared this after implementation:

var Letter : array[1..26] of char;
type
LetterList = record
Letter : char;

Thanx in advance for any help. Agian.

"ch := LetterList" is a statement. It has no return value, so no operators can be applied to it. You are trying to use "NOT". This looks like you have some C or Java background... Delphi / Pascal doesn't support the C-Way of assignments where you get the assigned value as return value.

ch := LetterList;
if NOT (ch<>0) err, nonsense: if ch=0 then...

(the NOT operator in Delphi can only be applied to boolean expressions)

hth,
M.