RE: remote debugger and upvalues with LUA 5.0a

["Nick Trout" <ntrout@...>]

> I currently have a remote debugger up and running. My problem 
> is that in
> some cases I can't properly evaluate expressions.
> 
> For example, lets have this script:
> 
> --- BEGIN
> local tmp = 3
> 
> function f ( n )
> 	return n + tmp
> end
> 
> --END
> 
> Then I load this script in memory, lua_dobuffer() it, with a 
> breakpoint in
> the body of f(). Then, lets say I want to evaluate tmp. My 
> problem is that
> tmp is an upvalue, therefore, when the interface sends a 
> query to evaluate
> the expression "return tmp", the debugger stub has no 
> information about the
> upvalue name. It only knows that f() has 1 upvalue, that's all.


Could you use luac output? Perhaps when you compile the code you could
keep the output handy in the client/PC side.

Perhaps my VmMerge script may be useful to you:
http://lua-users.org/wiki/VmMerge

From: http://doris.sourceforge.net/lua/weblua.php

instructions/20 bytes at 0x8052af0)
0 params, 2 stacks, 1 local, 1 string, 0 numbers, 1 function, 4 lines
     1	[1]	PUSHINT    	3
     2	[5]	GETLOCAL   	0	; tmp
     3	[5]	CLOSURE    	0 1	; 0x8052c70
     4	[5]	SETGLOBAL  	0	; f
     5	[5]	END

function <3:@/tmp/wlkeVHJJ> (5 instructions/20 bytes at 0x8052c70)
1 param, 3 stacks, 1 local, 0 strings, 0 numbers, 0 functions, 4 lines
     1	[4]	GETLOCAL   	0	; n
     2	[4]	PUSHUPVALUE	0          **** Upvalue ****
     3	[4]	ADD
     4	[4]	RETURN     	1
     5	[5]	END


I'm interested in this because I'll be writing a target debugger soon. I
was hoping I might be able to develop the wxWindows one I've been trying
to get going for ages (http://lua-users.org/wiki/VisLua) but it looks
like we're going the MFC route and there may be a lot of project
specific features. I did try and abstract the client and server
functionality so that it could be reused, see
http://lua-users.org/wiki/VisLuaImplementation Code sample allows you to
connect to remote Lua session (but no debugging yet). I got held up with
some bugs in wxWindows though, now they're on 2.3.4, maybe I'll give it
another go when I have some time.

Nick