method Expression.AddCustomOperator (Name as String, [Keyword as Variant], [ToolTip as Variant], [Type as Variant])
Adds a custom operator.

TypeDescription
Name as String A string expression that defines the name of the new operator to be added. The name should not contain any or # , " ' `( ). The name must not start with a digit character.
Keyword as Variant A HTML expression that specifies how the operator will be displayed in the control's context menu. You can press the CTRL + Space key to display the control's drop down that lists all available operators.
ToolTip as Variant A HTML expression that defines the operator's tooltip. For instance, the operator's tooltip may be displayed as soon as the cursor hovers the operator.
Type as Variant A OperatorTypeEnum expression that specifies the type of the operator. If missing, the method adds a keyword (exKeywordOperator).
The AddCustomOperator method allows you to add custom operators. The newly operator is added only if the Name is not already included and valid. The operator is valid if it includes no # , " ' `( ) characters, and not start with a digit character. No error occurs, if the AddCustomOperator method fails. The ClearCustomOperators method clears the custom operators. The AllowDefaultOperators property specifies whether the expression supports default operators. The AllowValueKeyword property specifies whether the expression supports the value keyword.

The following samples shows how you can define your own operators only:

VB 

With Expression1
	.AllowValueKeyword = False
	.AllowDefaultOperators = False
	.AddCustomOperator "+","<b>+</b>","This is a new binary-operator",2
	.AddCustomOperator "xxx","<b>xxx</b>","This is a new keyword",0
	.AddCustomOperator "yyy","<b>yyy</b>","This is a unary-operator",1
	.AddCustomOperator "zzz","<b>zzz</b>","This is a binary-operator",2
	.Text = "xxx + yyy(100 zzz 200)"
End With
VB.NET 
With Expression1
	.AllowValueKeyword = False
	.AllowDefaultOperators = False
	.AddCustomOperator("+","<b>+</b>","This is a new binary-operator",2)
	.AddCustomOperator("xxx","<b>xxx</b>","This is a new keyword",0)
	.AddCustomOperator("yyy","<b>yyy</b>","This is a unary-operator",1)
	.AddCustomOperator("zzz","<b>zzz</b>","This is a binary-operator",2)
	.Text = "xxx + yyy(100 zzz 200)"
End With

C++ 

/*
	Copy and paste the following directives to your header file as
	it defines the namespace 'EXPRESSIONLib' for the library: 'Expression 1.0 Control Library'

	#import <Expression.dll>
	using namespace EXPRESSIONLib;
*/
EXPRESSIONLib::IExpressionPtr spExpression1 = GetDlgItem(IDC_EXPRESSION1)->GetControlUnknown();
spExpression1->PutAllowValueKeyword(VARIANT_FALSE);
spExpression1->PutAllowDefaultOperators(VARIANT_FALSE);
spExpression1->AddCustomOperator(L"+","<b>+</b>","This is a new binary-operator",long(2));
spExpression1->AddCustomOperator(L"xxx","<b>xxx</b>","This is a new keyword",long(0));
spExpression1->AddCustomOperator(L"yyy","<b>yyy</b>","This is a unary-operator",long(1));
spExpression1->AddCustomOperator(L"zzz","<b>zzz</b>","This is a binary-operator",long(2));
spExpression1->PutText(L"xxx + yyy(100 zzz 200)");
C++ Builder 
Expression1->AllowValueKeyword = false;
Expression1->AllowDefaultOperators = false;
Expression1->AddCustomOperator(L"+",TVariant("<b>+</b>"),TVariant("This is a new binary-operator"),TVariant(2));
Expression1->AddCustomOperator(L"xxx",TVariant("<b>xxx</b>"),TVariant("This is a new keyword"),TVariant(0));
Expression1->AddCustomOperator(L"yyy",TVariant("<b>yyy</b>"),TVariant("This is a unary-operator"),TVariant(1));
Expression1->AddCustomOperator(L"zzz",TVariant("<b>zzz</b>"),TVariant("This is a binary-operator"),TVariant(2));
Expression1->Text = L"xxx + yyy(100 zzz 200)";
C# 
expression1.AllowValueKeyword = false;
expression1.AllowDefaultOperators = false;
expression1.AddCustomOperator("+","<b>+</b>","This is a new binary-operator",2);
expression1.AddCustomOperator("xxx","<b>xxx</b>","This is a new keyword",0);
expression1.AddCustomOperator("yyy","<b>yyy</b>","This is a unary-operator",1);
expression1.AddCustomOperator("zzz","<b>zzz</b>","This is a binary-operator",2);
expression1.Text = "xxx + yyy(100 zzz 200)";
JScript/JavaScript 
<BODY onload="Init()">
<OBJECT CLASSID="clsid:B33F5489-49AC-4155-98E7-9BBFC57FF019" id="Expression1"></OBJECT>

<SCRIPT LANGUAGE="JScript">
function Init()
{
	Expression1.AllowValueKeyword = false;
	Expression1.AllowDefaultOperators = false;
	Expression1.AddCustomOperator("+","<b>+</b>","This is a new binary-operator",2);
	Expression1.AddCustomOperator("xxx","<b>xxx</b>","This is a new keyword",0);
	Expression1.AddCustomOperator("yyy","<b>yyy</b>","This is a unary-operator",1);
	Expression1.AddCustomOperator("zzz","<b>zzz</b>","This is a binary-operator",2);
	Expression1.Text = "xxx + yyy(100 zzz 200)";
}
</SCRIPT>
</BODY>
VBScript 
<BODY onload="Init()">
<OBJECT CLASSID="clsid:B33F5489-49AC-4155-98E7-9BBFC57FF019" id="Expression1"></OBJECT>

<SCRIPT LANGUAGE="VBScript">
Function Init()
	With Expression1
		.AllowValueKeyword = False
		.AllowDefaultOperators = False
		.AddCustomOperator "+","<b>+</b>","This is a new binary-operator",2
		.AddCustomOperator "xxx","<b>xxx</b>","This is a new keyword",0
		.AddCustomOperator "yyy","<b>yyy</b>","This is a unary-operator",1
		.AddCustomOperator "zzz","<b>zzz</b>","This is a binary-operator",2
		.Text = "xxx + yyy(100 zzz 200)"
	End With
End Function
</SCRIPT>
</BODY>
C# for /COM 
axExpression1.AllowValueKeyword = false;
axExpression1.AllowDefaultOperators = false;
axExpression1.AddCustomOperator("+","<b>+</b>","This is a new binary-operator",2);
axExpression1.AddCustomOperator("xxx","<b>xxx</b>","This is a new keyword",0);
axExpression1.AddCustomOperator("yyy","<b>yyy</b>","This is a unary-operator",1);
axExpression1.AddCustomOperator("zzz","<b>zzz</b>","This is a binary-operator",2);
axExpression1.Text = "xxx + yyy(100 zzz 200)";
X++ (Dynamics Ax 2009) 
public void init()
{
	;

	super();

	expression1.AllowValueKeyword(false);
	expression1.AllowDefaultOperators(false);
	expression1.AddCustomOperator("+","<b>+</b>","This is a new binary-operator",COMVariant::createFromInt(2));
	expression1.AddCustomOperator("xxx","<b>xxx</b>","This is a new keyword",COMVariant::createFromInt(0));
	expression1.AddCustomOperator("yyy","<b>yyy</b>","This is a unary-operator",COMVariant::createFromInt(1));
	expression1.AddCustomOperator("zzz","<b>zzz</b>","This is a binary-operator",COMVariant::createFromInt(2));
	expression1.Text("xxx + yyy(100 zzz 200)");
}
VFP 
with thisform.Expression1
	.AllowValueKeyword = .F.
	.AllowDefaultOperators = .F.
	.AddCustomOperator("+","<b>+</b>","This is a new binary-operator",2)
	.AddCustomOperator("xxx","<b>xxx</b>","This is a new keyword",0)
	.AddCustomOperator("yyy","<b>yyy</b>","This is a unary-operator",1)
	.AddCustomOperator("zzz","<b>zzz</b>","This is a binary-operator",2)
	.Text = "xxx + yyy(100 zzz 200)"
endwith
dBASE Plus 
local oExpression

oExpression = form.EXPRESSIONACTIVEXCONTROL1.nativeObject
oExpression.AllowValueKeyword = false
oExpression.AllowDefaultOperators = false
oExpression.AddCustomOperator("+","<b>+</b>","This is a new binary-operator",2)
oExpression.AddCustomOperator("xxx","<b>xxx</b>","This is a new keyword",0)
oExpression.AddCustomOperator("yyy","<b>yyy</b>","This is a unary-operator",1)
oExpression.AddCustomOperator("zzz","<b>zzz</b>","This is a binary-operator",2)
oExpression.Text = "xxx + yyy(100 zzz 200)"
XBasic (Alpha Five) 
Dim oExpression as P

oExpression = topparent:CONTROL_ACTIVEX1.activex
oExpression.AllowValueKeyword = .f.
oExpression.AllowDefaultOperators = .f.
oExpression.AddCustomOperator("+","<b>+</b>","This is a new binary-operator",2)
oExpression.AddCustomOperator("xxx","<b>xxx</b>","This is a new keyword",0)
oExpression.AddCustomOperator("yyy","<b>yyy</b>","This is a unary-operator",1)
oExpression.AddCustomOperator("zzz","<b>zzz</b>","This is a binary-operator",2)
oExpression.Text = "xxx + yyy(100 zzz 200)"
Delphi 8 (.NET only) 
with AxExpression1 do
begin
	AllowValueKeyword := False;
	AllowDefaultOperators := False;
	AddCustomOperator('+','<b>+</b>','This is a new binary-operator',TObject(2));
	AddCustomOperator('xxx','<b>xxx</b>','This is a new keyword',TObject(0));
	AddCustomOperator('yyy','<b>yyy</b>','This is a unary-operator',TObject(1));
	AddCustomOperator('zzz','<b>zzz</b>','This is a binary-operator',TObject(2));
	Text := 'xxx + yyy(100 zzz 200)';
end
Delphi (standard) 
with Expression1 do
begin
	AllowValueKeyword := False;
	AllowDefaultOperators := False;
	AddCustomOperator('+','<b>+</b>','This is a new binary-operator',OleVariant(2));
	AddCustomOperator('xxx','<b>xxx</b>','This is a new keyword',OleVariant(0));
	AddCustomOperator('yyy','<b>yyy</b>','This is a unary-operator',OleVariant(1));
	AddCustomOperator('zzz','<b>zzz</b>','This is a binary-operator',OleVariant(2));
	Text := 'xxx + yyy(100 zzz 200)';
end
Visual Objects 
oDCOCX_Exontrol1:AllowValueKeyword := false
oDCOCX_Exontrol1:AllowDefaultOperators := false
oDCOCX_Exontrol1:AddCustomOperator("+","<b>+</b>","This is a new binary-operator",2)
oDCOCX_Exontrol1:AddCustomOperator("xxx","<b>xxx</b>","This is a new keyword",0)
oDCOCX_Exontrol1:AddCustomOperator("yyy","<b>yyy</b>","This is a unary-operator",1)
oDCOCX_Exontrol1:AddCustomOperator("zzz","<b>zzz</b>","This is a binary-operator",2)
oDCOCX_Exontrol1:Text := "xxx + yyy(100 zzz 200)"
PowerBuilder 
OleObject oExpression

oExpression = ole_1.Object
oExpression.AllowValueKeyword = false
oExpression.AllowDefaultOperators = false
oExpression.AddCustomOperator("+","<b>+</b>","This is a new binary-operator",2)
oExpression.AddCustomOperator("xxx","<b>xxx</b>","This is a new keyword",0)
oExpression.AddCustomOperator("yyy","<b>yyy</b>","This is a unary-operator",1)
oExpression.AddCustomOperator("zzz","<b>zzz</b>","This is a binary-operator",2)
oExpression.Text = "xxx + yyy(100 zzz 200)"
Visual DataFlex 
Procedure OnCreate
	Forward Send OnCreate
	Set ComAllowValueKeyword to False
	Set ComAllowDefaultOperators to False
	Send ComAddCustomOperator "+" "<b>+</b>" "This is a new binary-operator" 2
	Send ComAddCustomOperator "xxx" "<b>xxx</b>" "This is a new keyword" 0
	Send ComAddCustomOperator "yyy" "<b>yyy</b>" "This is a unary-operator" 1
	Send ComAddCustomOperator "zzz" "<b>zzz</b>" "This is a binary-operator" 2
	Set ComText to "xxx + yyy(100 zzz 200)"
End_Procedure
Xbase++ 
#include "AppEvent.ch"
#include "ActiveX.ch"

PROCEDURE Main
 	LOCAL oForm
	LOCAL nEvent := 0, mp1 := NIL, mp2 := NIL, oXbp := NIL
	LOCAL oExpression

	oForm := XbpDialog():new( AppDesktop() )
	oForm:drawingArea:clipChildren := .T.
	oForm:create( ,,{100,100}, {640,480},, .F. )
	oForm:close  := {|| PostAppEvent( xbeP_Quit )}

	oExpression := XbpActiveXControl():new( oForm:drawingArea )
	oExpression:CLSID  := "Exontrol.Expression.1" /*{B33F5489-49AC-4155-98E7-9BBFC57FF019}*/
	oExpression:create(,, {10,60},{610,370} )

		oExpression:AllowValueKeyword := .F.
		oExpression:AllowDefaultOperators := .F.
		oExpression:AddCustomOperator("+","<b>+</b>","This is a new binary-operator",2)
		oExpression:AddCustomOperator("xxx","<b>xxx</b>","This is a new keyword",0)
		oExpression:AddCustomOperator("yyy","<b>yyy</b>","This is a unary-operator",1)
		oExpression:AddCustomOperator("zzz","<b>zzz</b>","This is a binary-operator",2)
		oExpression:Text := "xxx + yyy(100 zzz 200)"

	oForm:Show()
	DO WHILE nEvent != xbeP_Quit
		nEvent := AppEvent( @mp1, @mp2, @oXbp )
		oXbp:handleEvent( nEvent, mp1, mp2 )
	ENDDO 
RETURN