6.4.18 The Operator -
This operator may only be used in the following ways:
record -
symbol
- This yields record without the attribute named symbol, if
symbol is an attribute name in record. If not, the
expression yields record.
record -
list
- Here, list must be a list of symbols. This yields record
without the attributes in list.
list -
number
- This yields list without the element at index number. If
this element does not exist, the expression yields list.
list1 -
list2
- This yields the multi-set difference of the two lists list1 and
list2. This means, it yields the list list1, but the first
n appearances of each element will be deleted, if that element
appears n times in list2.
number1 -
number2
- This yields the difference of number1 and number2.