Include other .bbc files in the main file?

[zachnoland]

I have a question. Can BBCSDL include other files inside the main file like MAIN.BBC and EXMATH.BBC, In EXMATH.BBC there are functions or procedures that can be called in MAIN.BBC.I don't know if this is possible on the original BBC Micro or not and i know this sounds like a modern programming language. But is this possible?

[Richard Russell]

I have a question. Can BBCSDL include other files inside the main file like MAIN.BBC and EXMATH.BBC, In EXMATH.BBC there are functions or procedures that can be called in MAIN.BBC.I don't know if this is possible on the original BBC Micro or not and i know this sounds like a modern programming language. But is this possible?

If I have understood your question correctly you can load such sub-modules using the INSTALL statement, in just the same way as you would the supplied libraries. The only difference is likely to be the file path from which the module is loaded:

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      INSTALL @lib$ + "aagfxlib" : REM Load supplied system library
      INSTALL @dir$ + "mymodule" : REM Load user-written sub-module

There's no difference, in essence, between a library and a sub-module, except that libraries have to follow more strict 'rules' because the circumstances in which they are going to be used are not known in advance. For example libraries should not normally create or access global variables whereas that may be acceptable with a sub-module.

There are a number of restrictions governing an INSTALLed sub-module or library which do not apply to regular programs:

1. It must be an internal-format (tokenised) program file, not a plain-text file.
2. You cannot use GOTO or GOSUB (lines may be numbered, but only for the purposes of debugging).
3. You can only use the 'relative' form of RESTORE.

This facility was not available on the BBC Micro (or 8-bit versions of BBC BASIC generally). The INSTALL and LIBRARY keywords were introduced by Acorn in ARM BASIC V in 1986; BB4W, BBCSDL and BBCTTY have INSTALL but they don't have LIBRARY (the difference is that a module loaded by INSTALL remains in memory for the rest of the 'session' whereas one loaded by LIBRARY is discarded as soon as the calling program terminates).

As a rule, when you see references to libraries in the documentation they apply just the same to sub-modules.

[zachnoland]

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      INSTALL @lib$ + "aagfxlib" : REM Load supplied system library
      INSTALL @dir$ + "mymodule" : REM Load user-written sub-module

I'm trying to understand how to load external files with:

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INSTALL @dir$ + "MYMATH2"

And it produces an error:

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file or path not found in line 10

I seem to have a problem with the file path issue in BBCSDL Android. The location of the MYMATH1.BBC and MYMATH2.BBC files are adjacent, meaning they were not changed before being saved in the same place or default. Maybe I should show you the code I typed.

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   10 REM MYMATH1.BBC
   20 INSTALL @dir$ + "MYMATH2" : REM LOAD SUB-MODULE
   30 A% = 5
   40 B% = 5
   50 PRINT FNMYADD(A%, B%)
   60 END
   

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   REM MYMATH2.BBC
   DEF FNMYADD(NUM1%, NUM2%)
      RESULTS% = NUM1% + NUM2%
   =RESULTS%
    

[Richard Russell]

I seem to have a problem with the file path issue in BBCSDL Android. The location of the MYMATH1.BBC and MYMATH2.BBC files are adjacent, meaning they were not changed before being saved in the same place or default.

My guess is that the issue here is that your files have a ".BBC" extension (capitals) but BBC BASIC is looking for a file with a ".bbc" extension (lowercase). If you omit the extension from the INSTALL statement, which you seem to be doing:

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   20 INSTALL @dir$ + "MYMATH2" : REM LOAD SUB-MODULE

BBC BASIC will automatically append the extension ".bbc", but since the Android file system is case-sensitive (as most are, apart from Windows and MacOS) that won't match your file. Either change the extension of your file to lowercase, or specify it explicitly in the INSTALL statement:

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   20 INSTALL @dir$ + "MYMATH2.BBC" : REM LOAD SUB-MODULE

[zachnoland]

My guess is that the issue here is that your files have a ".BBC" extension (capitals) but BBC BASIC is looking for a file with a ".bbc" extension (lowercase). If you omit the extension from the INSTALL statement, which you seem to be doing:

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   20 INSTALL @dir$ + "MYMATH2" : REM LOAD SUB-MODULE

BBC BASIC will automatically append the extension ".bbc", but since the Android file system is case-sensitive (as most are, apart from Windows and MacOS) that won't match your file. Either change the extension of your file to lowercase, or specify it explicitly in the INSTALL statement:

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   20 INSTALL @dir$ + "MYMATH2.BBC" : REM LOAD SUB-MODULE

I have tried changing the external file MYMATH2.BBC to mymathlib.bbc but it still produces the same error. Likewise, the main file MYMATH1.BBC becomes headertest.bbc and still gives error.

The question:

Could this be a bug?
If yes can you fix it?
Or maybe you have a solution for this.

One way I thought about but requires complete notes is, Maybe another solution is to add the complete file path structure of android but this will be very long and confusing.

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20 INSTALL @dir$ + "/storage/emulate/0/etc" : REM I don't remember all that path directory into the BBCSDL app lol

[Richard Russell]

Could this be a bug?

A bug in BBC BASIC? No, many of the supplied example programs would not work if it was, and a bug of that severity would have been found years ago (there are no known bugs in BBC BASIC for SDL 2.0).

It will almost certainly be something that you are doing wrong. Use the debugging capabilities of BBC BASIC (entering commands in Immediate Mode is probably the most useful in this case) to find out what.

For confirmation, I've just tested the INSTALL statement on my Android phone and it works perfectly:

Screenshot_2025-02-27-15-47-40-58_2f330f9510023cd121b7f55db302c4d3.jpg

[zachnoland]

It will almost certainly be something that you are doing wrong. Use the debugging capabilities of BBC BASIC (entering commands in Immediate Mode is probably the most useful in this case) to find out what.

For confirmation, I've just tested the INSTALL statement on my Android phone and it works perfectly:

Screenshot_2025-02-27-15-47-40-58_2f330f9510023cd121b7f55db302c4d3.jpg

I just realized something, the directory path is read depending on when opening the file directly or using interprenter immediate.bbc. This may be the reason why the code works if run directly. I just need to add double Dot like this.

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INSTALL @dir$ + "../mymathlib" : REM back to previous directory

this is the result i got:

Thank you the solution has been solved.

[Richard Russell]

I just realized something, the directory path is read depending on when opening the file directly or using immediate.bbc.

Yes, if you are entering immediate mode that way you will almost certainly find that @dir$ is pointing to where the immediate.bbc program itself is stored! It's usually better to enter immediate mode from the program that is in need of debugging, which is typically what will happen if an untrapped error occurs.

You could always put a copy of immediate.bbc in the same directory as the program you want to debug.

I just need to add double Dot like this.

Hmm. 'Resource' files (that is, files that programs need in addition to the program itself, such as sub-modules, graphics images, sound effects etc.) should be stored either in the same directory as the program, or in a sub-directory thereof. So they would be loaded something like this:

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      INSTALL @dir$ + "mymodule.bbc" : REM Same directory as program
      INSTALL @dir$ + "myresources/modules/mymodule.bbc" : REM Sub-directory

They should not be stored in a parent directory (@dir$ + "../parent...") because if you do that any attempt to build a standalone executable (or in the case of Android a self-contained APK) will fail.

So whilst it may be working for you at the moment, I would review how you are organising your project so that you would be able to build a standalone executable or application if you wanted to.