| Chapter 15. The Language Utilities (UTIL) Component | ||
|---|---|---|
 | Part II. C-Language Components |  |
Table of Contents
This component provides a common location for utility types and functions that are important but not worth including in the core language component.
The dlist type consists of a doubly-linked list of
dnode objects. Instead of being a ring, this provides a
first and a last property (with
the obvious meanings). It also provides a method of retrieving the count
of nodes, and the nodes at the beginning and the end of a list refer to
.nul in their properties for the appropriate direction
(either next or prev).
Objects of type dlist have no value, and it is an error to try to get or set this value.
| Property | Type | Description |
|---|---|---|
| _ | type(*) | This property is provided for use by the user to attach any object of any type to the type in which this property is provided. |
| __ | type(*) | This property is provided for use by the user to attach any object of any type to the type in which this property is provided. It has the additional feature of being marked with the resolve keyword, so that object resolution can continue down this property. |
| first | dnode |
This is the first node in the list. If there are no elements in the
list, then this will be .nul.
|
| last | dnode |
This is the last node in the list. If there are no elements in the
list, then this will be .nul.
|
| type | type | Specifies the dlist type object. |
This clears the nodes from a list and makes any nodes that are still referred to anywhere into a complete ring. This means that the nodes still exist, they simply aren't part of the list any more, unless none of the nodes are referred to by any other variable, in which case they will no longer exist.
Returns the node from the list corresponding to the index value
passed as the parameter. The first node has the index value
1 and the last node will have an index value equal
to that returned by the count() method.
Inserts the node passed as the first node in the list. If the node
is part of a ring consisting of more than one node, then the ring
will be broken following the node passed and all entries will be
inserted prior to that node which will then have the former first
node of the list (if any) as its next node and
it will become the prev node of the former first
node. If, for example, there is a rings of nodes: a, b, c (,
a, b, …) and a list x containing:
d, e, f, and then the call:
x.insertfirst(b) is made, then the result in
x will be: c, a, b, d, e, f. It
is an error to pass a node to this method if that node is already in
a list.
Inserts the node passed as the last node in the list. If the node is
part of a ring consisting of more than one node, then the ring will
be broken following the node passed and all entries will be inserted
prior to that node, the first of which will then have the former last
node of the list (if any) as its prev node and
it will become the next node of the former last
node. If, for example, there is a rings of nodes: a, b, c (,
a, b, …) and a list x containing:
d, e, f, and then the call:
x.insertlast(b) is made, then the result in
x will be: d, e, f, c, a, b. It
is an error to pass a node to this method if that node is already in
a list.
| |  | |
| odbc2_fetchandsaverecords() |  | dnode |
