User-defined functions

LSL allows user-defined functions. The syntax is very simple:

return_type variable_name(par1type par1name, par2type par2name,...)
  {
    function_statements;
    .
    .
    .
    return value_of_return_type;
  }

There are no "function" or "def" keywords or function type/inheritance specifiers needed. I have not yet discovered what limits (if any) exist on the length or composition of the parameter list. Multiple types can be used, as shown in the example below. A list can be returned, so a single function can return a list with several values in it. User-defined functions will help keep scripts compact and readable, and allow rudimentary code reuse. The LSL_Style_Guide suggests that user-defined functions should be placed before the default state definition and after user-defined variables. Placing user-defined functions after the first state will result in a Syntax Error.

Here are a couple of simple examples:

float xsquared(float x)   // return the square of the argument
{
    return x*x;
}

vector scalarmult(vector vIn, float sMult)  // return the product of a scalar and a vector
{
    vIn.x=vIn.x*sMult;
    vIn.y=vIn.y*sMult;
    vIn.z=vIn.z*sMult;
    return vIn;
}



default
{
    state_entry()
    {
        llWhisper(0, "Some user functions");
    }

    touch_start(integer total_number)
    {
        float testx=3;
        llWhisper(0,"testx squared :"+(string)xsquared(testx));
        vector testVector = <1,2,3>;
        testVector = scalarmult(testVector,testx);
        llWhisper(0,"test vector is:"+(string)testVector);
    }
}