Converting MINI-BASIC in MASM over to C++?

**Sebastiani** · 03-19-2009

Got it.

**Sebastiani** · 03-19-2009

Ok, so this update contains the implementation for 'EvalExpr', and the 'LET' command, plus some other minor changes. Let me know if I broke anything.

Paul, just thought I'd let you know that it still has a way to go before you'll be able to test it out, but it is coming along...

**Paul Panks** · 03-19-2009

Ok, thanks Sebastiani.

Paul

**phantomotap** · 03-19-2009

I took a look at the code... the original is a bad dog.

Before I jump into this, which I may if time allows, may I at least suggest updating the API test to do something useful?

Soma

Code:

void mbox_error_handler
(
   const std::string & from_f,
   const std::size_t where_f,
   const bool show_f
)
{
   if(show_f)
   {
      const DWORD buffer_length(256);
      char message_buffer[buffer_length];
      const DWORD characters_written = FormatMessageA
      (
         FORMAT_MESSAGE_FROM_SYSTEM,
         0, // lpSource (ignored here)
         GetLastError(),
         0, // dwLanguageId (use system defaults)
         message_buffer,
         buffer_length,
         0 // Arguments (pointless VA_LIST nonsense)
      );
      std::ostringstream message;
      if(0 == characters_written)
      {
         message
            << "File: " << from_f << '\n'
            << "Line Number: " << where_f << '\n'
            << "Error Message:\n"
            << "unknown exception"
         ;
      }
      else
      {
         message_buffer[characters_written - 2] = 0;
         message
            << "File: " << from_f << '\n'
            << "Line Number: " << where_f << '\n'
            << "Error Message:\n"
            << message_buffer
         ;
      }
      MessageBoxA
      (
         0, // hWnd (no owner)
         message.str().c_str(),
         "WIN32API Exception",
         MB_ICONERROR | MB_OK | MB_TASKMODAL
      );
   }
}

#define WINAPITEST(BADVALUE, RESULT) mbox_error_handler(__FILE__, __LINE__, BADVALUE == RESULT)

**Sebastiani** · 03-19-2009

>> I took a look at the code... the original is a bad dog.

I couldn't agree more.

>> may I at least suggest updating the API test to do something useful?

That's a good idea. And since API errors are basically fatal, you might as well just have the program die at that point.

**matsp** · 03-19-2009

Agreed - I was going to do something like that, but I hadn't got round to it.

Can we just do a small change:

Code:

#define WINAPITEST(RESULT, EXPECTED) mbox_error_handler(__FILE__, __LINE__, RESULT == EXPECTED)

By putting names there, it's easier to see what is what.
--
Mats

**matsp** · 03-19-2009

Originally Posted by phantomotap

I took a look at the code... the original is a bad dog.

I'm pretty sure I said something like that when I started the work - it's definitely not easy-to-follow, straight-forward assembly code. Lots of jumps. One of my favourites was a bit that did

Code:

pop ebx    // get return address
add ebx, 2
jmp ebx

to skip over a jmp instruction in the calling code. That is hard to achieve in C or C++.

I'm going to have a quick look at Sebastianis change's, but do not expect me to do much with it until Monday.

In the mean-time, keep up the good work.

--
Mats

**Paul Panks** · 03-19-2009

Ok, thanks.

Paul

**matsp** · 03-19-2009

A couple of comments on the updated code:
1. what is #include <std> for?
2. In VS 2008, the loss of const in RedimWindow() doesn't work.

I also think we should keep the functionality of RedimWindow - there is a "WINDOW" command in the language itself that uses it. I believe existing code would break if you remove that command.

It may well be that some situations do not allow completely free re-sizing of windows, but it should still be there for those apps that can/want to do it.

--
Mats

**Sebastiani** · 03-19-2009

Oh, the header include was just for debugging purposes. Ignore it.

As far as RedimWindow goes, it just needs to be restructured so that it takes on a default value when the program starts up, and then if the user tries to resize the window and it fails, it just reverts back to the default without causing a fatal error.

**Sebastiani** · 03-19-2009

For some reason the documentation in MBI.zip doen't list all of the functions (such as WINDOW, LOCATE, etc). Anyone have a complete listing?

**matsp** · 03-19-2009

Originally Posted by Sebastiani

For some reason the documentation in MBI.zip doen't list all of the functions (such as WINDOW, LOCATE, etc). Anyone have a complete listing?

There is a complete listing in the original source...

--
Mats

**Sebastiani** · 03-19-2009

Ha! Yeah, I admit it, I was trying to avoid looking at the assembly...

**matsp** · 03-19-2009

Originally Posted by Sebastiani

Ha! Yeah, I admit it, I was trying to avoid looking at the assembly...

That may or may not be a good idea. To make it "binary compatible" with the existing assembly code, I think reading documentation may not be sufficient.

--
Mats