TExprBuiltInManager.AddFunction function

Member of TExprBuiltInManagerpublicIn unit fpExprPars

Add function to built-in collection

Declaration

pascal

function AddFunction(const ACategory: TBuiltInCategory; 
 const AName: ShortString; 
 const AResultType: AnsiChar; 
 const AParamTypes: AnsiString; 
 ACallBack: TFPExprFunctionCallBack)
: TFPBuiltInExprIdentifierDef
function AddFunction(const ACategory: TBuiltInCategory; 
 const AName: ShortString; 
 const AResultType: AnsiChar; 
 const AParamTypes: AnsiString; 
 ACallBack: TFPExprFunctionEvent)
: TFPBuiltInExprIdentifierDef
function AddFunction(const ACategory: TBuiltInCategory; 
 const AName: ShortString; 
 const AResultType: AnsiChar; 
 const AParamTypes: AnsiString; 
 ANodeClass: TFPExprFunctionClass)
: TFPBuiltInExprIdentifierDef

Arguments

`ACategory`	Category for the function
`AName`	Name of the function
`AResultType`	Result type for the function
`AParamTypes`	Parameter types for the function
`ACallBack`	Callback function for the built-in
`ANodeClass`	Node class for the function

Function result

Returns the added function identifier

Description

The AddFunction method adds a custom function to the built-in collection, making it available for use in expressions. The function must provide appropriate callback or event handling mechanisms for evaluation.

Built-in functions extend the expression language with domain-specific functionality, allowing applications to provide mathematical, string, date/time, or business-logic functions that can be called from within expressions.

An experiment, built from development snapshots. Not the official Free Pascal or Lazarus documentation.