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Basic operations on Lists include assignment, concatenation, conversions, length, and comparisons.
Assignment for Lists is done with the assignment (=)
operator.
The statement L1 = L2; destroys the
contents of List L1 and replaces them with a
copy of the elements in List L2.
The return value of an assignment expression is the object assigned, so
L1=L2=L3; works as expected.
The plus (+) operator is used for concatenation.
If L1 and L2
are both Lists, then L1 + L2 is a new List whose
elements are a copy of those of L1 followed by
a copy of those of L2.
Also, +
can be used with a List and a T, so that L+t is
a new List whose elements are those of List L followed
by t.
Coercions from Ts to List<T>s are implemented
by the constructor functions for class List<T>.
For example, whenever a T is found where a List<T>
is expected, the appropriate List<T> constructor
function is called to produce a List containing just that element.
Also, whenever a List is used as an expression, for example,
while(L), it is converted to a void*
automatically so that it can be evaluated as TRUE or FALSE.
The expression will
be TRUE if the List is nonempty, and FALSE otherwise.
L.length() returns the length (number of
elements) of the List<T> L.
The == and != operators are used for comparisons of Lists.
L1 == L2 is TRUE if each element of
L1 is equal (that is, T::operator==()
is nonzero) to the corresponding element of L2.
L1 != L2 is TRUE otherwise.