Still don't understand to make filename match title

Although I have used computers for decades, have read your manual, and have done a bit of programming in FORTRAN and C, I still don't understand your instructions. I simply want the "titles" of all my mp3 files to match the "filename." (It seems like a no-brainer that 95% of everyone would want this, so why is it not the default?) I would gladly donate, if you could create a simple macro to accomplish this fete, apart from having to do all of this %$? programming.

This will not be possible for titles that feature characters that the are invalid for filesystem.
Filenames may also have length restrictions.

Should the filename get the content of your current TITLE?
Or should the TITLE get the current filename?

I originally created all of the filenames (xyz.mp3), and they are currently correct. The titles need to be the same as the filenames. When I created the file names, I had no idea the title would be different. Why would anyone ever want two names for the same file? Doesn't make much sense.

Oh, we could leave off the ".mp3", as one of your users already noted

The filenames are designed so that the songs play in the correct sequence. (01 xyz.mp3, 02 xyz.mp3, 03 xyz.mp3, etc.)

This should be all you neee to manage what you are asking.

Some prefer to include things like disc and track numbers, the Artist, or other things they feel are important in their individual cases. Everyone manages their libraries in their own way.

What program did you use for ripping these files? It would be that app that set the metadata.

I simply want the "titles" of all my mp3 files to match the "filename."

look here:

opens:

(#4 will fill in automatically once you select the field you want)
And no, not everyone would like the titles to be equal to the filenames. I for one will have information like "composer - year - artist - title" in the filename, visible from the "outside" and reflect only the ´"title" in the field title, because I can access the rest of the information otherwise (in the player).

Usually my player does not need the filename to determine any kind of play order but uses the data in the tags.
In your case

it would mean that the filename should be split in TRACK and TITLE to get decently structured data. But this would be something that you have to tell the program and that cannot be overcome with

If you want to get several macros for different cases then you would have to be able to address them somehow. And as there are so many possible combinations that need to be covered the most flexible way is

(BTW: for a simple transfer of data from the filename or to the filename, you do not need $ and ?.)

That makes much sense.
Because you can't write a filename with exactly this TITLE content:
Question: Is 3 * 2 > then 14 / 7 ?

In the TITLE tag you can write whatever you want.
In the filename - at least under Windows - you have several restrictions. For example you can't use/write these characters in a filename:

< (less than)
> (greater than)
: (colon)
" (double quote)
/ (forward slash)
\ (backslash)
| (vertical bar or pipe)
? (question mark)
* (asterisk)

That's why many of us use the TITLE tag to display the complete, unrestricted songname and then use the filename as good as its possible with the given restrictions by the operating system ("Windows").