OpenEuphoria

Re: Include dir as built-in function

• Posted by Jason Gade <jaygade at ?ahoo.co?> Apr 29, 2008
• 629 views

Marco Achury wrote:
> 
> I understand that is important to keep the interpreter small.
> 
> But I don't understand why there are a lot of function at include as:
> 
> global function dir(sequence name)
> -- returns directory information, given the name
> -- of a file or directory. Format returned is:
> -- {
> --  {"name1", attributes, size, year, month, day, hour, minute, second},
> --  {"name2", ...                                                     },
> -- }
>     return machine_func(M_DIR, name)
> end function
> 
> The function is really just one line of code.  M_DIR is a constant 
> with value 22.
> 
> The include files are plenty of this kind of functions.
> ¿How big is the effect on interpreter speed/size if some 
> of this functions become internals.
> 
> Another example is function wait_key(), this is strongly used on 
> text mode apps, like ED.EX.
> 
> global function wait_key()
> -- Get the next key pressed by the user.
> -- Wait until a key is pressed.
>     return machine_func(M_WAIT_KEY, 0)
> end function
> M_WAIT_KEY is a constant = 26
> 
> What gives better performance?  As built-in 
> or as include?
> 
> +-+-+-+-+-+-+-+
> Marco A. Achury
> Caracas, Venezuela

Those functions are internal (hence the machine_func() call). The reason is to
avoid polluting the namespace and also probably to keep the actual reserved words
in the parser relatively small.

I think. Someone else could probably explain it better.

--
A complex system that works is invariably found to have evolved from a simple
system that works.
--John Gall's 15th law of Systemantics.

"Premature optimization is the root of all evil in programming."
--C.A.R. Hoare

j.