Take a look at this code:
trace(1 + + 2); // Output: 3
It may seem strange to us, but ActionScript considers it legal. It assumes you mean:
trace(1 + (+2));
which produces the value 3.
Now take a look at this code:
// Oops! One too many + signs...
trace("Hello" +
+ " world");
Once again, ActionScript assumes you mean:
trace("Hello" +
(+ " world"));
which yields the following somewhat misleading error:
1067: Implicit coercion of a value of type String to an unrelated type Number.
The error occurs because ActionScript considers '(+ "world")' a datatype-conversion operation, not a String concatenation. The fix is simple: remove one + sign.
trace("Hello"
+ " world");
But why does ActionScript consider '(+ "world")' a datatype conversion? Francis Cheng explains here...
Posted by moock at August 1, 2008 04:39 AM