TExprBuiltInManager¶

Class for managing built-in functions and variables in expressions

Declaration¶

Source position: fpexprpars.pp line 804

type

  TExprBuiltInManager = class(TComponent)
  public
    constructor Create;
    destructor Destroy;
    function IndexOfIdentifier : Integer;
    function FindIdentifier : TFPBuiltInExprIdentifierDef;
    function IdentifierByName : TFPBuiltInExprIdentifierDef;
    function AddVariable : TFPBuiltInExprIdentifierDef;
    function AddBooleanVariable : TFPBuiltInExprIdentifierDef;
    function AddIntegerVariable : TFPBuiltInExprIdentifierDef;
    function AddFloatVariable : TFPBuiltInExprIdentifierDef;
    function AddCurrencyVariable : TFPBuiltInExprIdentifierDef;
    function AddStringVariable : TFPBuiltInExprIdentifierDef;
    function AddDateTimeVariable : TFPBuiltInExprIdentifierDef;
    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;
    procedure Delete;
    function Remove : Integer;
    property IdentifierCount: Integer; {r}
    property Identifiers[AIndex : Integer]: TFPBuiltInExprIdentifierDef; {r}
  end;

Inheritance¶

Description¶

The TExprBuiltInManager class serves as a manager for built-in functions and predefined variables that can be used within expressions. It provides a centralized registry where built-in mathematical functions, string functions, date/time functions, and system variables are registered and made available to the expression parser.

The manager handles the registration, lookup, and instantiation of built-in functions when they are encountered during expression parsing. It also maintains predefined variables such as system constants that can be referenced in expressions.

The TExprBuiltInManager class allows for extensibility by enabling the registration of custom built-in functions and variables that should be available across all expression evaluations.

Properties¶

Member	Visibility	Description
IdentifierCount read only	public	Number of built-in identifiers
Identifiers read only	public	Array access to built-in identifiers

See all Properties

Methods¶

Member	Visibility	Description
AddBooleanVariable	public	Add boolean variable to built-in collection
AddCurrencyVariable	public	Add currency variable to built-in collection
AddDateTimeVariable	public	Add datetime variable to built-in collection
AddFloatVariable	public	Add float variable to built-in collection
AddFunction	public	Add function to built-in collection
AddIntegerVariable	public	Add integer variable to built-in collection
AddStringVariable	public	Add string variable to built-in collection
AddVariable	public	Add variable to built-in collection
Create	public	Create built-in manager instance
Delete	public
Destroy	public	Destroy built-in manager instance
FindIdentifier	public	Find built-in identifier by name
IdentifierByName	public	Get identifier by name with exception on not found
IndexOfIdentifier	public	Find index of built-in identifier
Remove	public

See all Methods