Harbour -> XSharp migration: function calls/returns

[RolWil]

Hi all,

X# newbie here.

I’d like to migrate a very large Harbour application (which had a prior life in Clipper) to XSharp for a client who has been using it for 25+ years. It’s pretty much still standard Clipper code.

I’ve just started to experiment with X#; It appears that most folks are migrating from either VO or VFP though so I’m not finding much help on the subject. In order to make this feasible for my client, I need to minimize code re-write other than the presentation layer. Most of the business logic is in a number of function libraries, the system was written quite modular for its time.

One of my first tests involves a simple call to a function with a return value:

bValue := AnyFunc()
return
function AnyFunc()

return(.t.)

This works in Harbour.


However, in XSharp, I get error “XS1031 Type expected” unless I code the function as

function AnyFunc() as boolean


Do I have to re-write hundreds of functions or is there a setting in ‘Language’ or ‘Dialect’ I should be setting.

Thanks.

[wriedmann]

Hi Roland,
you may need more options, but to compile code with undefined variables you need at least the dialect Harbour and the options /lb (allow late bound calls), /memvar (support memvar, public, private) and /undeclared (support undeclared variables).
Then this code compiles:

Code: Select all

function Start( ) as void
	System.Console.WriteLine("Hello x#!")

	bValue := AnyFunc()

	return

function AnyFunc()

	return(.t.)

05-04-2023_07-27-48.png (35.92 KiB) Viewed 1010 times

Wolfgang

[wriedmann]

Hi Roland,
after moving your code you should think about strong typing your variables and functions to have better and much, much faster code.
Check out this code:

Code: Select all

function Start(  ) as void
	local nWeak
	local nStrong as int
	local dStart as DateTime

	System.Console.WriteLine("start, not typed")
	dStart := DateTime.Now		
	for nWeak := 1 to 10000000
		nop
	next
	System.Console.WriteLine("ended, not typed, duration " + ( DateTime.Now - dStart ):ToString() )
	
	System.Console.WriteLine("start, typed")
	dStart			:= DateTime.Now		
	for nStrong := 1 to 10000000
		nop
	next
	System.Console.WriteLine("ended, typed, duration " + ( DateTime.Now - dStart ):ToString() )
	
return

You may be surprized..... but the most important thing is the much better control at compile time.

Wolfgang

[Chris]

Hi Roland,

As Wolfgang said, you need to set the Dialect to Harbour, and this will also require you to add references to the libraries XSharp.Core and XSHarp.RT. If you do not know how to do this, please just ask.

About /undeclared and /memvar, you need to set those options if needed, but if the vars you use are always defined with LOCAL statements, then this will not be needed. Most likely you will also need to enable /vo7 too pass parameters by reference, but that depends on the code.

Btw, is the app using @SAY GET commands for the presentation? If yes, we may have a solution so that you can keep also that code (almost) unchanged, but show the command line windows as regular windows using WinForms.

[RolWil]

Thanks for all your kind and speedy responses; great group!

I had missed your suggested 'Implicit Casts' and 'Late Binding' settings. I now included them and still get that 'Type Expected' error. I've included screen grabs of my updated settings.

I agree that I should cast all variables but the time do to so and subsequent testing would likely make the task impossible, it's roughly 32,000 lines of code.

Chris, I'm curious about your suggestion re @ SAY/GET.

Again, thanks so much for your help.

Roland

[wriedmann]

Hi Roland,
unfortunately I don't use Visual Studio, but Chris's excellent XIDE, so I don't know what is missing in your configuration to compile without errors. The settings your screenshots show are correct, but I suspect there is something that they don't get applied.
Maybe they are different between the application and the project setting?
Regarding typing: of course it is not possibile to change them all, but touching the most time critic code could help.
After all, 32.000 lines of code is not that much - I have applications with more than 500.000 lines, and I know there are some (VO) applications ported to X# with more than a million of lines.
Wolfgang

[robert]

Roland
Please enable the option “treat missing types as usual”
Robert

[Chris]

Rolland,

Regarding @SAY...GET commands, some time ago we had built a system that uses the already existing code unchanged and maps the commands to real controls (edit boxes, combo boxes etc) in real windows, so no code rewrite was necessary, only some window design in the (visual) window editor, to put the controls in nice places, group them in group controls etc. It was created to the specific needs and app (also written in Harbour) code of another customer, but I suspect that with some changes it can be adjusted to work with any codebase.

I'd say let's have a look first on the business code side of things, to see how easy it is to reuse it in X# (but keep in mind, that even if something does not work, we can most probably improve it quickly), and if you're satisfied with that part, then we can look into the visual side of things as well.

.

[RolWil]

Thank you Robert, earlier on, I did a 'quick reply' to your message, but I can't see it. Gremlins. Your tip did the trick! Thanks!

[RolWil]

Thanks Chris, I'll keep that in mind. Ideally, I'll re-write the presentation layer and hook it into the existing 'back-end'. This legacy system is very heavy on calculations and database activity, less so on visuals.