calcfun.dpr

源码,数学表达式解析器,可以解析并自动计算输入的公式

library calcfun;

{ Important note about DLL memory management: ShareMem must be the
  first unit in your library's USES clause AND your project's (select
  Project-View Source) USES clause if your DLL exports any procedures or
  functions that pass strings as parameters or function results. This
  applies to all strings passed to and from your DLL--even those that
  are nested in records and classes. ShareMem is the interface unit to
  the BORLNDMM.DLL shared memory manager, which must be deployed along
  with your DLL. To avoid using BORLNDMM.DLL, pass string information
  using PChar or ShortString parameters. }

uses
  SysUtils,
  Classes,
  expclass in 'expclass.pas';

const
  CALCERR = -999999999999.99;

function CalcExp(AExpression: PChar):Extended; stdcall;
var
  cExp: TExpression;
begin
  cExp := TExpression.Create(Aexpression);
  try
    if cExp.oResok then
      Result := cExp.Calc
    else
      Result := CALCERR;
  finally
    cExp.Free;
  end;
end;

function CalcExp2(AExpression: PChar; var Res: extended):boolean; stdcall;
var
  cExp: TExpression;
begin
  cExp := TExpression.Create(Aexpression);
  try
    Res := cExp.Calc;
    Result := cExp.oResok;
  finally
    cExp.Free;
  end;
end;

exports
  CalcExp,
  CalcExp2;

begin
end.