A "do" is really the "do... until" statement as you cannot have
one without the other. It has this form:
do <statement> until (<expression>)
The statement (which can also be a code block) is executed until
the expression is found true, and the initial statement is always
executed at least once. Be careful with your do loops, as you can
easily make them loop forever, in which case your game will hang
and not react to any user input anymore. Below you can find an
example of a typical way to use "do... until":
{
do
{
x = random(room_width);
y = random(room_height);
}
until (place_free(x, y)); }
The above program tries to place the current object at a free
position (this is about the same as the action to move
an object to a random position).