<Struct TypeSpec> ::= MP_CommonOperatorPkt(MP_Struct)n<MP TypeSpec>n
A collection of (possibly heterogeneous) objects to be
treated as logically related is described using a
The number of arguments field specifies both the number
of actual arguments the operator has in the Prototype tree and
the number of data items to be read from the data packet that follows
the Prototype tree.
The arguments to the struct operator specify the
types of the arguments individually using MP TypeSpecs.
Figure 4 shows how a sparse matrix can
be represented (see also Figures 1 and
2 for comparison).
Note that the statically defined representation in Figure
required 48 bytes and the prototyped version requires only 76 bytes,
but the size of the prototype remains constant.