Canot call functions defined in script in Lazarus 1.8.0 FPC 3.0.4

[Former user]

I try to execute Test\Algorithms\dot_product.pas script and got error in Lazarus. Script defines function and then calls it. It looks like to me that result variable could not be placed correctly in stack. I got error because FStackAddr variable which is used as Index in stack array is -3. I think free pascal do not support negative indexes. Is it same in Delphi?

Debuger shows that error is here in dwsCoreExprs.pas:

// AssignValueAsFloat
//
procedure TFloatVarExpr.AssignValueAsFloat(exec : TdwsExecution; const value: Double);
begin
   exec.Stack.WriteFloatValue_BaseRelative(FStackAddr, value);
end;

dot_product.pas content:

function DotProduct(a, b : array of Float) : Float;
require
   a.Length = b.Length;
var
   i : Integer;
begin
   Result := 0;
   for i := 0 to a.High do
      Result += a[i]*b[i];
end;

PrintLn(DotProduct([1,3,-5], [4,-2,-1]));  

Code which execute script is:

  Script := TDelphiWebScript.Create(Self);
  try           
    f := TFileStream.Create('C:\dwscript\Test\Algorithms\dot_product.pas', fmOpenRead);
    Source := TStringStream.Create('');
    Source.CopyFrom(F, 0);
    F.Free;
    Source.Position := 0;
    prog := Script.Compile(Source .DataString);
    Source.Free;

    if prog.Msgs.Count=0 then
    begin
      exec:=prog.Execute;
      DbgOut(exec.Result.ToString);
    end
    else
      DbgOut(prog.Msgs.AsInfo)
  finally
    exec := nil;
    prog := nil;
    Script.Free
  end 

[imantsg]

I created fix for this problem is it possible to somehow share it with you

[imantsg]

I think I understood how to create pull requests

[Eric Grange]

Does the following work in Lazarus/FPC ?

If yes this could avoid the need for an ifdef as it compiles similarly to existing code in Delphi.

function TStackMixIn.GetBaseData(index : Integer) : PVarData;
begin
   Result := PVarData(NativeUInt(FBaseData) + NativeUInt(Index * SizeOf(Variant)));
end;

[imantsg]

It looks like that this is working in Lazarus/FPC. I updated my pool request.

[Eric Grange]

Don't worry to much on the pull request, I cannot use it directly (this repo is synched from an SVN repo...)

I committed changes with your fixes, let me know if that's ok

[imantsg]

It is OK. I will delete my pull request then. I thin you can resolve this issue. At leas I do not see how I can do it.