Functions and Directives Functions and Directives

Function Type() Foundation

Determines the data type of an expression.

Syntax
Type( <cExpression> ) --> cType
Parameters
<cExpression>
<cExpression> is a character string which describes an expression. This can contain the name of PRIVATE or PUBLIC variables, a field name or the call to a globally visible function in character form.
Return

The return value of Type() is one or two characters which specify the data type of the value of <cExpression>. The following table lists the possible data types and return values of Type():

Data types and return values of Type()
Return value Data type
A array
B code block
C character string
D date value
L logical value
M memo field
N numeric value
O object
U NIL or unknown
UE Syntactically faulty expression

Description

Type() is a debugging function which determines the data type of an expression passed in the form of a character string. Type() returns a character string identifying the data type. The function determines the data type using the macro operator (&), which means the character expression is executed and the data type of the result determined. Type() differs from the function Valtype(). Valtype() determines the data type directly so can also determine the data type of variables declared as LOCAL or STATIC.

Examples
Type() 
// The example shows possible return values of Type() 

PROCEDURE Main 
   MEMVAR  oGet 
   PRIVATE oGet := GetNew() 

   ? Type( "{1,2,3}" )           // result: A 
   ? Type( "{|| 1 }" )           // result: B 
   ? Type( "'Xbase++'" )         // result: C 
   ? Type( "Date()" )            // result: D 
   ? Type( ".T." )               // result: L 
   ? Type( "1" )                 // result: N 
   ? Type( "Customer->notice" )  // result: M 
   ? Type( "oGet" )              // result: O 
   ? Type( "Val(" )              // result: UE 
   ? Type( "NIL" )               // result: U 

RETURN
Difference between Type() and Valtype() 

// The example demonstrates the difference between Type() and 
// Valtype() with variables and functions of different 
// visibility or storage class. Type() uses the macro 
// operator to determine the data type of an expression 
// in form of a character string. Valtype() determines the 
// data type of the expression directly. 

PROCEDURE Main 
   LOCAL cArray := "{1,2,3}" 

   MEMVAR  pnNumeric 
   PRIVATE pnNumeric := 10 

   ? Valtype( cArray )         // result: C 
   ?    Type( cArray )         // result: A   (contents of LOCAL) 

   ? Valtype( "cArray" )       // result: C 
   ?    Type( "cArray" )       // result: U   (LOCAL variable) 

   ? Valtype( "pnNumeric" )    // result: C 
   ?    Type( "pnNumeric" )    // result: N   (contents of PRIVATE) 

   ? Valtype( GlobalFunc() )   // result: L   (function value) 
   ?    Type("GlobalFunc()")   // result: L   (function value) 

   ? Valtype( StaticFunc() )   // result: N   (function value) 
   ?    Type("StaticFunc()")   // result: U   (STATIC FUNCTION) 

RETURN 

FUNCTION GlobalFunc() 
RETURN .T. 

STATIC FUNCTION StaticFunc() 
RETURN 100
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