dws2variantfunctions.pas

script language

{**********************************************************************}
{                                                                      }
{    "The contents of this file are subject to the Mozilla Public      }
{    License Version 1.1 (the "License"); you may not use this         }
{    file except in compliance with the License. You may obtain        }
{    a copy of the License at                                          }
{                                                                      }
{    http://www.mozilla.org/MPL/                                       }
{                                                                      }
{    Software distributed under the License is distributed on an       }
{    "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express       }
{    or implied. See the License for the specific language             }
{    governing rights and limitations under the License.               }
{                                                                      }
{    The Original Code is DelphiWebScriptII source code, released      }
{    January 1, 2001                                                   }
{                                                                      }
{    The Initial Developer of the Original Code is Matthias            }
{    Ackermann.                                                        }
{                                                                      }
{    Portions created by Matthias Ackermann are Copyright              }
{                        (C) 2000 Matthias Ackermann, Switzerland.     }
{                                                                      }
{    All Rights Reserved.                                              }
{                                                                      }
{    Contributor(s):                                                   }
{                                                                      }
{**********************************************************************}

{$I dws2.inc}

unit dws2VariantFunctions;

interface

uses
  Classes, dws2Functions, dws2Exprs, dws2Symbols;

type
  TNullFunc = class(TInternalFunction)
    procedure Execute; override;
  end;

  TUnassignedFunc = class(TInternalFunction)
    procedure Execute; override;
  end;

  TVarClearFunc = class(TInternalFunction)
    procedure Execute; override;
  end;

  TVarIsNullFunc = class(TInternalFunction)
    procedure Execute; override;
  end;

  TVarIsEmptyFunc = class(TInternalFunction)
    procedure Execute; override;
  end;

  TVarAsTypeFunc = class(TInternalFunction)
    procedure Execute; override;
  end;

implementation

uses
{$IFDEF NEWVARIANTS}
  Variants,
{$ENDIF}
  SysUtils;

const // type constants to make sure strings get reused by the compiler
  cFloat = 'Float';
  cInteger = 'Integer';
  cString = 'String';
  cBoolean = 'Boolean';
  cVariant = 'Variant';

{ TVarClearFunc }

procedure TVarClearFunc.Execute;
begin
  Info['v'] := Unassigned;
end;

{ TVarIsNullFunc }

procedure TVarIsNullFunc.Execute;
begin
  Info.Result := VarIsNull(Info['v']);
end;

{ TVarIsEmptyFunc }

procedure TVarIsEmptyFunc.Execute;
begin
  Info.Result := VarIsEmpty(Info['v']);
end;

{ TUnassignedFunc }

procedure TUnassignedFunc.Execute;
begin
  Info.Result := Unassigned;
end;

{ TNullFunc }

procedure TNullFunc.Execute;
begin
  Info.Result := Null;
end;

{ TVarAsTypeFunc }

procedure TVarAsTypeFunc.Execute;
begin
  Info.Result := VarAsType(Info['v'], Info['VarType']);
end;

initialization
  RegisterInternalFunction(TNullFunc, 'Null', [], cVariant);
  RegisterInternalFunction(TUnassignedFunc, 'Unassigned', [], cVariant);
  RegisterInternalFunction(TVarClearFunc, 'VarClear', ['@v', cVariant], '');
  RegisterInternalFunction(TVarIsNullFunc, 'VarIsNull', ['v', cVariant], cBoolean);
  RegisterInternalFunction(TVarIsEmptyFunc, 'VarIsEmpty', ['v', cVariant], cBoolean);
  RegisterInternalFunction(TVarAsTypeFunc, 'VarAsType', ['v', cVariant, 'VarType', cInteger], cVariant);
end.