Used at module level to set the default data type for variables, arguments passed to procedures, and the return type for Function and Property Get procedures whose names start with the specified characters.
DefBool letterrange[, letterrange] . . .DefByte letterrange[, letterrange] . . .DefInt letterrange[, letterrange] . . .DefLng letterrange[, letterrange] . . .DefCur letterrange[, letterrange] . . .DefSng letterrange[, letterrange] . . .DefDbl letterrange[, letterrange] . . .DefDate letterrange[, letterrange] . . .DefStr letterrange[, letterrange] . . .DefObj letterrange[, letterrange] . . .DefVar letterrange[, letterrange] . . .
The argument letterrange has the following syntax:
letter1[-letter2]
The letter1 and letter2 arguments specify the name range for which you can set a default data type. Each argument represents the first letter of the variable, argument, Function procedure, or Property Get procedure name and can be any letter of the alphabet. The case of letters in letterrange isn’t significant.
The statement name determines the data type:
| Statement | Data Type |
| DefBool | Boolean |
| DefByte | Byte |
| DefInt | Integer |
| DefLng | Long |
| DefCur | Currency |
| DefSng | Single |
| DefDbl | Double |
| DefDate | Date |
| Statement | Data Type |
| DefStr | String |
| DefObj | Object |
| DefVar | Variant |
For example, in the following program fragment, Message is a string variable:
DefStr A-Q . . .= "Out of stack space."
A Deftype statement affects only the module where it is used. For example, a DefInt statement in one module affects only the default data type of variables, arguments passed to procedures, and the return type for Function and Property Get procedures declared in that module; the default data type of variables, arguments, and return types in other modules is unaffected. If not explicitly declared with a Deftype statement, the default data type for all variables, all arguments, all Function procedures, and all Property Get procedures is Variant.
When you specify a letter range, it usually defines the data type for variables that begin with letters in the first 128 characters of the character set. However, when you specify the letter range A – Z, you set the default to the specified data type for all variables, including any that begin with international characters from the extended part of the character set (128 – 255).
Once the range A – Z has been specified, you can’t further redefine any subranges of variables using Deftype statements. In fact, once a range has been specified, if you include a previously defined letter in another Deftype statement, an error occurs. However, you can explicitly specify the data type of any variable, defined or not, using a Dim statement with an As type clause. For example, you can use the following code at module level to define a variable as a Double even though the default data type is Integer:
DefInt A-ZTaxRate As Double
Deftype statements don’t affect elements of user-defined types since the elements must be explicitly declared.
Function Statement, Let Statement, Property Get Statement.
This example shows various uses of the Deftype statements to set default data types of variables and function procedures whose names start with specified characters. The default data type can be overridden only by explicit assignment using the Dim statement. Deftype statements can only be used at the module level (that is, not within procedures).
' Variable names beginning with A through K default to Integer.A-K
' Variable names beginning with L through Z default to String.L-Z= 4 ' Initialize Integer.= "Hello there" ' Initialize String.= "Hello" ' Causes "Type mismatch" error.Calc As Double ' Explicitly set the type to Double.= 2.3455 ' Assign a Double.
' Deftype statements also apply to function procedures.= ATestFunction(4) ' Call user-defined function.
' ATestFunction function procedure definition.ATestFunction(INumber)
ATestFunction = INumber * 2 ' Return value is an integer.Function