Class TRbwParser

Operators contains the names of the single character operators.

name contains the names of the operators that have two or more characters in their names.

Signs contains the names of the sign operators.

See TSpecialImplementorList and SpecialImplementorList.

FCurrentExpression: TExpression; See CurrentExpression.

FExpressions: TStringList; See Expressions.

FFunctions: TFunctionStringList; See Functions.

FVariables: TStringList; See Variables.

FOwnedVariables: TObjectList; FOwnedVariables holds all the TCustomVariables owned by the TRbwParser.

FOpereratorDefinitions contains a series of TOperatorDefinitions.

See Expressions.

See Variables.

DefineNotOperator defines the "not" operator.

DefinePlusSignOperator defines the "+" sign operator.

DefineMinusSignOperator defines the "-" sign operator.

DefineTimesOperator defines the "*" operator.

DefineDivideOperator defines the "/" operator.

DefineDivOperator defines the "div" operator.

DefineModOperator defines the "mod" operator.

DefineAndOperator defines the "and" operator.

DefinePlusOperator defines the "+" (addition or concatenation) operator.

DefineMinusOperator defines the "-" (subtraction) operator.

DefineOrOperator defines the "or" operator.

DefineXorOperator defines the "xor" operator.

DefineEqualsOperator defines the "=" operator.

DefineNotEqualsOperator defines the "<>" operator.

DefineLessThanOperator defines the "<" operator.

DefineGreaterThanOperator defines the ">" operator.

DefineLessThanOrEqualsOperator defines the "<=" operator.

DefineGreaterThanOrEqualsOperator defines the ">=" operator.

AddOperator adds an operator to the operators recognized by TRbwParser. The TRbwParser will take ownership of the TOperatorDefinition but not of any TOperatorArgumentDefinition that it has.

RemoveOperator will remove the TOperatorDefinition whose OperatorName is OperatorName.

ClearExpressions destroys all compiled TExpressions in the TRbwParser.

If several TRbwParsers are used and variables owned by one are used in another one, ClearExpressions and ClearVariables should be called in all of them before any of them is destroyed.

ClearVariables removes all variables from the list of variables used by TRbwParser but does not free them (because they may be used by another TRbwParser).

If several TRbwParsers are used and variables owned by one are used in another one, ClearExpressions and ClearVariables should be called in all of them before any of them is destroyed.

CreateVariable creates a TBooleanVariable owned by TRbwParser and allows it to be used with the TRbwParser.

See also: RegisterVariable.

CreateVariable creates a TIntegerVariable owned by TRbwParser and allows it to be used with the TRbwParser.

See also: RegisterVariable.

CreateVariable creates a TRealVariable owned by TRbwParser and allows it to be used with the TRbwParser.

See also: RegisterVariable.

Example:

      procedure TForm1.Button2Click(Sender: TObject);
      var
        Index : integer;
        Variable : TRealVariable;
      begin
        RbwParser1.CreateVariable('A', 2.5);
        RbwParser1.CreateVariable('B', 3.5);
        RbwParser1.Compile('A + B');
        RbwParser1.CurrentExpression.Evaluate;
        Label1.Caption := 'result: '
          + FloatToStr(RbwParser1.CurrentExpression.DoubleResult);
        // Label1.Caption is set to "result: 6".
        Index := RbwParser1.IndexOfVariable('a');
        // variable names are not case sensitive.
        Variable := RbwParser1.Variables[Index] as TRealVariable;
        Variable.Value := 6.5;

        RbwParser1.CurrentExpression.Evaluate;
        Label2.Caption := 'result: '
          + FloatToStr(RbwParser1.CurrentExpression.DoubleResult);
        // Label2.Caption is set to "result: 10".
        // As it stands, this event handler would cause
        // an error if it was called twice because
        // it would try to create variables named "A" and "B" twice.
        // Calling ClearVariables would prevent this if that is
        // what you really want to do.
      end;
      

CreateVariable creates a TStringVariable owned by TRbwParser and allows it to be used with the TRbwParser.

See also: RegisterVariable.

Compile searches for AString in Expressions. If it finds it, it sets CurrentExpression to that TExpression and returns it's position in Expressions. If it doesn't find it, Compile converts AString into a TExpression, sets CurrentExpression to the TExpression it created, adds the TExpression to Expressions and returns the position of the TExpression in Expressions.

Expressions are owned by TRbwParser.

Create creates an instance of TRbwParser;

DeleteExpression destroys the TExpression at Index and deletes it from the list of Expressions.

Destroy destroys the TRbwParser. Do not call Destroy directly. Call Free instead.

ExpressionCount returns the number of TExpressions in Expressions.

IndexOfVariable locates the TCustomVariable whose name is VariableName in Variables and returns it's position. If it is not in Variables it returns -1.

RegisterVariable allows a TCustomValue to be used by the TRbwParser even though the TCustomValue isn't owned by the TRbwParser.

RemoveExpression deletes Expression from the list of Expressions and destroys it.

If Variable is owned by or registered with TRbwParser, RemoveVariable removes it and, if it is owned by the current instance of TRbwParser, also destroys it. It also destroys any TExpressions in the current TRbwParser that use Variable.

RenameVariable changes the name of the variable at position Index to a NewName and changes Index to the new position of the variable.

VariableCount is the number of variables in Variables.

See: TSpecialImplementorList.

CurrentExpression is the most recently Compiled TExpression.

Expressions is an array of TExpressions.

Functions stores TFunctionClasses in it's Objects property and manages the TFunctionClasses used by TRbwParser.

Variables is an array of variables (TCustomValues) used by the current TRbwParser.