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Paula script example: a script that prints 20 Fibonacci numbers (n=20).

n:20; i:0; a:0; b:1
while(i < n)
	c:a+b
	print(c, " ")
	a:b; b:c
	i:i+1

C++ callback example: create a C++ callback and call it from script.

const paula::Error* myCallback (paula::Args&args) {
  for (int i=0; i<args.count(); i++) {
    char * value;
    if (args.get(i).getChars(value)) {
      std::cout<<"arg "<<i<<": "<<value<<std::endl;
    }
  }
  return NO_ERROR;
}

void main()
{
  // register a callback for Paula engine
  auto error = paula::addCallback("test", myCallback);
  // call it from a script
  error = paula::run("test(\"foo\", \"bar\")");
}

If you run the code, it prints

arg 0: foo
arg 1: bar

For technical information and to try it yourself see the GitHub project:	Doxygen docs for programmers:
GitHub: paula-script	Paula C++ API

What is a scripting language?

Computer programs or apps consist of

• Machine code: instructions that tell CPU what to do.
• Data: pictures, text, scripts, etc. that the app uses.

Scripts control computer programs by instructions, written in some scripting language, like Python or JavaScript... or Paula! A common example of a scripting language in use is JavaScript, which is used by web pages to add functionality.

CPU (Central Processing Unit) is a microprocessor and the "brain" of the computer, smart phone, or other electronic gadget. It reads and executes the machine code to make the app run.

Machine code is executed by the CPU whereas scripts are interpreted and executed by the program.

Inside the machine code is the script interpreter that does what the script it tells it to do. So, the CPU executes the script interpreter (Paula), and the interpreter executes the script, if that makes any sense.

Economic scripting

Paula (meaning "small" in Latin) is a compact language designed to take up minimal space in a program. This is especially important in constrained environments, such as electronic devices, where the interpreter, other code, and scripts must all fit within a limited memory (RAM). If the interpreter is too big, you just can't use it. In addition to being compact, Paula is designed to be suitable for environments without such resource limitations, providing the needed flexibility while remaining secure and efficient, something between archaic and extravagant.

Memory allotion

Most script interpreters allocate memory for their use during runtime. Allocated memory is freed when it's not needed anymore.

Usually, this approach is fine and practical. Problems arise, however, if more memory is allocated than is available, causing the program to slow down or crash. This can happen, for example, when large files are loaded into memory for processing.

In Paula, this issue does not occur because it doesn't allocate memory during runtime at all. Paula's users can be confident that it won't cause unpleasant surprises due to excessive memory allocation.

The downside is that the user must know how much memory Paula will need and define it when launching the program. However, the guarantee that users can specify the required memory themselves provides a sense of security and reliability to Paula's users.

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Meanwhale, 2025