Item Utility Routines
The following routines allow you to fold, spindle and otherwise manipulate individual items within an object.
OT CompareItems version 1
OT CompareItems(inSourceObject; inSourceTag; inCompareObject; inCompareTag) Number
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Parameter Type Description
inSourceObject Longint A handle to an object
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inSourceTag String An item tag
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inCompareObject Longint A handle to an object
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inCompareTag String An item tag
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Function result Number 0 if not identical, 1 if identical, -1 if
← an error occurred
Discussion
OT CompareItems compares two items for equality. inSourceObject and inCompareObject may be the same object.
If inSourceObject or inCompareObject is not a valid object handle, if either of the two items do not exist, or if the two items do not have the same type, an error is generated, OK is set to zero, and -1 is returned.
Otherwise, the items are compared according to the rules of equality used for equivalent variable types in 4D, with the addition that you may compare BLOB, Picture and embedded object items. These additional types are considered identical if they contain the same data byte for byte.
OT RenameItem version 2
OT RenameItem(inObject; inTag; inNewTag)
Parameter Type Description
inObject Longint A handle to an object
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inTag String A full item tag
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inNewTag String The new item tag
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Discussion
OT RenameItem renames the item referenced by inTag to the item referenced by inNewTag. Note that inTag must be a full tag if the target item is in an embedded object, whereas inNewTag is the new item name only. For example:
OT RenameItem($obj;"foo.bar.old_name";"new_name")
The above example will rename the item old_name to new_name within the embedded object foo.bar. To access the renamed item you would use the tag "foo.bar.new_name".
If the object handle is invalid, or if the item does not exist, or if an existing item has the same name as inNewTag, an error is generated, OK is set to zero, and no rename is performed.
OT CopyItem version 1
OT CopyItem(inSourceObject; inSourceTag; inDestObject; inDestTag)
Parameter Type Description
inSourceObject Longint A handle to an object
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inSourceTag String An item tag
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inDestObject Longint A handle to an object
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inDestTag String An item tag
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Discussion
OT CopyItem copies the item referenced by inSourceTag to the item referenced by inDestTag. The item referenced by inDestTag need not exist; it will be created if necessary. The source and destination objects may be the same, allowing either duplication of an item at the same level of embedding within an object, or copying an item from one level of embedding to another.
If either object handle is not valid, or if the source item does not exist, or if the source item and destination item do not have the same type, an error is generated, OK is set to zero, and no copy is performed.
Note Copying an embedded object copies all of its items.
OT DeleteItem version 1
OT DeleteItem(inObject; inTag)
Parameter Type Description
inObject Longint A handle to an object
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inTag String Tag of the item to delete
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Discussion
OT DeleteItem deletes an item from an object. inTag may refer to embedded items and objects.
If inObject is not a valid object handle or inTag refers to an item that does not exist, an error is generated, OK is set to zero, and no delete is performed.
Note Deleting an embedded object deletes all of its items.