Side effect with string buffer and function calls

In processors smaller than PIC18, PMP uses only one string temporary buffer for space reduction.

In another side, there's no stack where to save a string buffer.

In this context there is a special side effect when there is a function call in a string expression if there is also a string expression in the called function.

Consider the following code:

FUNCTION Func1: string;
 BEGIN
   // assume that Var1 contains #13
   Func1 := '-foo' + Var1 + 'bar-';
 END;

StringVar := 'hello' + Func1 + 'world';

StringVar will contain '-foo' + #13 + 'bar-' + 'world' because 'hello' was pushed in the string buffer and the string buffer has been destroyed in the Func1 function.

• An expression such as 'hello' + 13 + 10 + 'world' + 13 + 10 does not use the string buffer since it is evaluated at compile time. String buffer is used only if the expression contains non-constant sub expressions.