Usage: x
Weak comparison: true iff either x or y is absent, or both occur and the value of x is less than the value of y.
Usage: x<=y
Weak comparison: true iff either x or y is absent, or both occur and the value of x is less than or equal to the value of y.
Usage: x>y
Weak comparison: true iff either x or y is absent, or both occur and the value of x is greater than the value of y.
Usage: x>=y
Weak comparison: true iff either x or y is absent, or both occur and the value of x is greater than or equal to the value of y.
Return optional 0/1 integer that is absent iff x is absent, and 1 iff x occurs and is true.
Return absent if idx is absent, otherwise return x[idx]
Return absent if idx1 or idx2 is absent, otherwise return x[idx1, idx2]
Return x[idx]
Return x[idx1, idx2]
Return absent if idx is absent, otherwise return x[idx]
Return absent if idx1 or idx2 is absent, otherwise return x[idx1, idx2]
True iff both x and y are absent or both are present and have the same value.
True iff only one of x and y is absent or both are present and have different values.
Return maximum of elements in x that are not absent, or absent if all elements in x are absent.
Return minimum of elements in x that are not absent, or absent if all elements in x are absent.
True iff x is not absent
Return sum of non-absent elements of x.
Weak multiplication. Return product of x and y if bothare present, otherwise return absent.
Weak addition. Return sum of x and y if bothare present, otherwise return absent.
Weak subtraction. Return difference of x and y if bothare present, otherwise return absent.
Weak equality. True if either x or y are absent, orpresent and equal.