SmallBASIC Git

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FAQ for developers

* Apology to developers

	The SB was a small interpreter.
	It was builded to serve some mathematical calculations for my palm, my old Palm IIIx with OS 3.3.
	This weird beginning produced weird problems.

	a) PalmOS 3.3 is extremly limited on resources such memory, and speed.

		1) The compiler (and parts of RTL) is based to use less resource as it can.
			That means, a few static buffers that will reused (very dangerous) instead of
			other types such as stack or "heap". It is a very bad technique but required.

		2) Use of custom memory manager for virtual-memory techniques.

		3) Use of arrays instead of lists. That is prefered because lists need one more element per node
			(the 'next' pointer) 
			plus some OS-related data used internaly by the OS for each "node" (because it is dynamic allocation).
			In 32kB of PalmOS 3.3 that was useless spend of a very rare resource. So, by using arrays with "realloc"
			when it was needed, I solve the problem with dynamic data. I am still thinking how to do a 
			mixed way depented on the target OS.

		5) The work for driver-developers it was possible to be extremly easy if I had the 
			power to use function-pointer. But that was actually impossible since Palm version of SB is
			multi-segment code (function-pointer had no info about the code-segment in run-time stage).

	b) From a toy to a language.

		1) I must rewrite evaluation-code because it is a bit mess (source-code) but produces excellent
			output like a normal compiler. That happened because SB was interpreter.

		2) Classical definitions such as lexer, scanner etc... does not exists on SB.
			Part of its history and part of PalmOS 3.3 problems, those parts are not
			written with a good structure nor are separated enough.


* What is the SEC() on header files?
	The SEC(code-segment-name) declares on which code-segment will be stored the function.
	That is usefull only for PalmOS. So, forget it, on linux this declared as "nothing".

* Virtual-file-driver?
	
	See fs_serial.c and after that the file.c