This method first compares the identity of the object's class (see
the
id
method of the Class class) to
classid. If they are the same, the
receiver object is returned as the result.
Otherwise,
request
tries to obtain and return an object satisfying
classid by sending the receiver object the
conversion message
make with
the string
classid appended (converted to
uppercase). For example,
a
request("string") message causes a
makeString message to be sent.
If the object does not have the required conversion method,
request returns
.nil.
The conversion methods cause objects to produce different representations
of themselves. The presence or absence of a conversion method defines an object's
capability to produce the corresponding representations. For example, lists
can represent themselves as arrays, because they have a
makeArray method,
but they cannot represent themselves as directories, because they do not have
a
makeDirectory
method. Any conversion method must return an object of the
requested class. For example,
makeArray
must return an array. The language
processor uses the
makeString
method to obtain string values in certain contexts;
see
Section 4.2.11, “Required String Values”.
