I just read the full post and I have some questions. Note I have never programmed in tiBasic so maybe some of these questions are weird...
- a code-editor + interpreter + compiler. (all 3 together in one programme)
1 why would you write your own code-editor instead of letting people choose whatever editor they want?
2. You do not need an interpreter and a compiler. You either compile it so it runs nativly or run it through and interpreter I don't really see any reason to have both...
- the .exe itself: The only way to execute a game.
- subprogramme-subfolder: The compiler can compile .exe-files and .subp-files.
Explanation following...
- sound-subfolder: Contains all sound data. Sounddata is accessible directly
through code in the programme. It is stored in .tis-files.
(the synth/sequencer produces .tis-files) (I just made up
that filetype. Smiley )
- data-file: In this file (probably a .bin?) all variable-data of the
application itself is being stored. The application can edit
it's existing data-file.
ok so a subprogram is bassically just a function right? That's what it seems to me. By a .exe file I assume you mean an executable file of any type. This is what you'd get from a compiler so I still don't understand the interpreter thing.
About this data file. What do you mean that's were the variable-data is being stored. Variable data would be stored in memory. Do you mean this is where data can be saved to disk by the program? If you want all the variables to be here then this should only be done on exit as you don't want be constantly reading from the disk..
About the commands the only ones I see as being actual language keywords are
the math ones (even then these could be functions c++ style)
#
if
stop
return
lbl
goto
repeat
while
and the logic commands
Everything else you listed seemed like just a built in function (not that this is bad the fewer keywords the easier it is to right the compiler in general)
Overall I wouldn't want to write a compiler (as I have no experience and that would mean a different compiler for all os's)
What I could see myself doing is writing a program that simply converts this code into c code or some other popular language and then that can be compiled for whatever os. Would that be applicable with your vision

?
Also writing a converter seems pretty doable and then people could implement all the functions as they wished. I had to write an emulator of similar complexity last year and I had to write it in this random integrated system assembly so writing it in java would be much easier
