TFPExprFunction¶

Internally used class for representing function calls in expression trees

Declaration¶

Source position: fpexprpars.pp line 625

type

  TFPExprFunction = class(TFPExprIdentifierNode)
  public
    procedure Check;
    constructor CreateFunction;
    destructor Destroy;
    procedure InitAggregate;
    procedure UpdateAggregate;
    function HasAggregate : Boolean;
    property ArgumentNodes: TExprArgumentArray; {r}
    property ArgumentParams: TExprParameterArray; {r}
    function AsString : AnsiString;
  end;

Inheritance¶

Description¶

The TFPExprFunction class represents a function call node in the expression tree. It serves as the base class for all function implementations that can be called from within expressions, including mathematical functions, string functions, date/time functions, and user-defined functions.

The class manages function parameters, validates argument types and counts, and provides the framework for function evaluation. It handles the common aspects of function calls such as parameter management and type checking.

Derived classes implement specific functions by overriding the evaluation methods and providing function-specific logic. The class supports functions with varying numbers of parameters and different return types.

This class is used internally by the TFPExpressionParser class to construct an AST (Abstract Syntax Tree). There is normally no need for you to use or instantiate this class directly.

Properties¶

Member	Visibility	Description
ArgumentNodes read only	public	The argument nodes for the function
ArgumentParams read only	public	The argument parameters for the function

See all Properties

Methods¶

Member	Visibility	Description
AsString	public	Get string representation of function expression
Check	public	Validate the function expression
CreateFunction	public	Create function with identifier and arguments
Destroy	public	Destroy function expression and free resources
HasAggregate	public	Check if function contains aggregates
InitAggregate	public	Initialize aggregate processing for function
UpdateAggregate	public	Update aggregate calculations for function

See all Methods