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    TExprBuiltInManager.AddFunction

    Add function to built-in collection

    Declaration

    Source position: fpexprpars.pp line 824

    public 
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;

    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.