An lvalue is the left hand side of an assignment. In other words, an lvalue is what you assign something to. Valid lvalues are:
a
Identifier. Here we would be setting the variable of name
a.
*a
Dereference of an identifier. This will set whatever variable
a points to.
a@(<region>)A region of a matrix. Here the region is specified normally as with the regular @() operator, and can be a single entry, or an entire region of the matrix.
Examples:
a:=4 *tmp := 89 a@(1,1) := 5 a@(4:8,3) := [1,2,3,4,5]'
Note that both := and = can be used
interchangeably. Except if the assignment appears in a condition.
It is thus always safer to just use
:= when you mean assignment, and ==
when you mean comparison.