Item Types
Like 4D variables, every item in an object has a distinct type which can be accessed. When an item is created by putting a value into an object, it is assigned the type that was specified by the OT Put<type> call. Except for character types and embedded objects, the type of an item is identical to the equivalent 4D type.
ObjectTools defines several special item types for items that have no representation within 4D. Each of these types has a named constant defined which can be used to determine the item’s type.
Constant Type Value
| OT Is Character | Characters | 112 |
| OT Character array | Character array | 113 |
| OT Is Object | Embedded ObjectTools object | 114 |
| OT Is Record | Record data | 115 |
Except for character types, you must get values from objects with the same type used to put the value. In other words, the <type> in OT Put<type> and OT Get<type> must match. Otherwise ObjectTools will generate an error and return a null value. For example:
C_LONGINT($object)
$object:=OT New
OT PutReal ($object;"my real";13.27)
C_LONGINT($bad)
$bad:=OT GetLong ($object;"my real") `This generates an error
C_REAL($real)$real:=OT GetReal ($object;"my real") `This is okay
The Character Item Type
Any characters put in an object, whether they start life as a String or as Text, have the item type OT Is Character.
Character items can be retrieved either as a String or as Text via OT GetString, OT GetText, or OT GetVariable. For example:
OT PutString ($object;"chars";"this was originally a string")
C_TEXT($text)$text:=OT GetText ($object;"chars")
$text:="this was originally text"
OT PutText ($object;"chars";$text)
C_STRING(8;$str8)
$str8:=OT GetString ($object;"chars") `$str8 will now contain "this was"
Likewise, any String or Text arrays put into an object are stored with an item type of OT Character array (113). Elements of this item type can then be retrieved either as a fixed width String or as Text via OT GetArrayString and OT GetArrayText .