Const Variables and when they are declared

[nitekram]

It might not need to be fixed, but I found it strange that Const are not checked first, before everything else. I wrote a UDF and I used/declared a Const variable in the main script, but when I went to compile the script, I got a warning message stating that my variable was not declared in one of my included UDFs, yet I declared it in the main script. Once I put the Const variable declaration above the include statement for the UDF, the warning went away.

I guess I thought that Const variables would be declared first above all else, as they are constants? With that in mind, a UDF that declares Const values would need to be put before any UDF's that were to use that Const...I would think that would be a nightmare, to have to make sure one UDF is above another one for declarations.

Is this by design, and can it be changed?

 

On another note, after you close the script, the warning UDF is opened in Scite, making it a bit of a pain to have to go back to the original script. And in order for me to get rid of the warning in my UDF, I have to go to the line above it and hit delete, then hit enter, to make the format correct again. I have even tried Tidy and that only works sometimes - can we also look at fixing that hotkey, to remove any Scite messages in the script - no, not the lines inputted by Tidy, but the ones before Tidy is ran.

[jchd]

AutoIt uses an interpretor and no real compilation takes places. That means that inside the final executable code things remain in the order they have in the source code. So if you declare a constant or variable after an include file which uses it, it won't be known at the moment it's referenced. Call this "by design" and only a real compiler would be needed to overcome the situation, implying that you shouldn't hold your breath until available.

[nitekram]

OK, so no 'real compiler' - understood.

What about the other request - is that doable? Or is that by design too?

[jchd]

You'll have to see that with Jos I suppose.

[guinness]

Best practices would be to adopt the same approach as in C with header files, in which you have your UDF called MyWonderfulUnicornRainbow.au3 and then a separate file that declares all the constants that will be used within that UDF, called MyWonderfulUnicornRainbowConstants.au3. DON'T declare a constant in your main script that you use elsewhere in other UDFs, as then you're looking for trouble. Same is for Global variables too.

[nitekram]

So is there a way to use a declaration that says if not declared, declare it...I mean how do you not use a variable in other parts of the program, that might be listed in another file, as if I declared it in every file, I would get an error stating that it was already declared?

 

 

[guinness]

No, unless you like using IsDeclared()? Which is ugly and should only be used with Assign() & Eval() and not variables declared the traditional way i.e. Global Const $MYVAR = 10

What I am saying, is place your Global constants in a script file, add #include-once to the top of it and include in each script that you need those constants using #include "MyConstants.au3".

How do you think we do it in the UDFs? HINT: #include-once.

Edited May 7, 2015 by guinness