TFPConstExpression class
Internally used class for constant value expressions
Declaration
TFPConstExpression = class(TFPExprNode)Inheritance
- TFPConstExpression
- TFPExprNode
- TObject
Description
The TFPConstExpression class represents constant literal values in expressions,
storing fixed values that do not change during expression evaluation. It provides the foundation for all literal constants including strings,
integers, floats, booleans, and date/time values.
Constant expressions are the leaf nodes of expression trees that provide actual data values rather than computed results. They are essential building blocks that supply the raw data that other expression nodes operate on.
The class handles various data types through different constructor methods and provides type-safe storage and retrieval of constant values during expression evaluation.
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.
See also
Properties
ConstValue | public | The constant value stored in the expression |
Methods
CreateString | public | Create constant expression with string value |
CreateInteger | public | Create constant expression with integer value |
CreateDateTime | public | Create constant expression with datetime value |
CreateFloat | public | Create constant expression with float value |
CreateBoolean | public | Create constant expression with boolean value |
CreateCurrency | public | Create constant expression with currency value |
Check | public | Validate the constant expression |
NodeType | public | Get the result type for constant expressions |
GetNodeValue | public | Get the constant value |
AsString | public | Get string representation of constant expression |
Inherited
From TFPExprNode (6)
CheckNodeType HasAggregate InitAggregate IsAggregate NodeValue UpdateAggregate
From TObject (42)
AfterConstruction BeforeDestruction CheckDisposed ClassInfo ClassName ClassNameIs ClassParent ClassType CleanupInstance Create DefaultHandler DefaultHandlerStr Destroy Dispatch DispatchStr Disposed DisposeOf Equals FieldAddress Free FreeInstance GetDisposed GetHashCode GetInterface GetInterfaceByStr GetInterfaceEntry GetInterfaceEntryByStr GetInterfaceTable GetInterfaceWeak GetLastCastErrorInfo InheritsFrom InitInstance InstanceSize MethodAddress MethodName newinstance QualifiedClassName SafeCallException StringMessageTable SystemHasExtendedRTTI ToString UnitName
An experiment, built from development snapshots. Not the official Free Pascal or Lazarus documentation.