There are only a few language constructs in Prolog, and several ways for indenting them are common.
No matter which style is chosen, one principle that should always be adhered to is to never place
(;)/2 at the end of a line. This is because
, look very similar, and
, frequently occurs at the end of a line. Therefore, clauses that use a disjunction should for example be written as:
( Goal1 ; Goal2 )