TCaseOperation¶

Internally used class for case-when conditional operations

Declaration¶

Source position: fpexprpars.pp line 279

type

  TCaseOperation = class(TFPExprNode)
  public
    procedure Check;
    procedure InitAggregate;
    procedure UpdateAggregate;
    function HasAggregate : Boolean;
    function NodeType : TResultType;
    constructor Create;
    destructor destroy;
    function AsString : AnsiString;
    property Condition: TFPExprNode; {r}
  end;

Inheritance¶

Description¶

The TCaseOperation class implements case-when conditional operations in expressions, providing multi-way branching logic based on value matching. It allows for testing a single expression against multiple possible values and executing different branches based on which value matches.

The case operation evaluates a test expression and compares it against a series of when-value pairs, executing the associated expression for the first matching value. If no values match, an optional else expression is evaluated.

The TCaseOperation class enables complex multi-conditional logic within expressions, similar to CASE statements in SQL or switch statements in programming languages, providing an alternative to nested if-then-else constructs.

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
Condition read only	public	The condition expression of the case operation

See all Properties

Methods¶

Member	Visibility	Description
AsString	public	Get string representation of case operation
Check	public	Validate the case operation for correctness
Create	public	Create case operation with arguments
destroy	public	Destroy case operation and free resources
HasAggregate	public	Check if case operation contains aggregates
InitAggregate	public	Initialize aggregate processing for case operation
NodeType	public	Get the result type for case operation
UpdateAggregate	public	Update aggregate calculations for case operation

See all Methods