Support of Prolog prologue #102
Description
Are there any plans to support the Prolog prologue? So far, from the 15 predicates agreed so far, 8 are missing completely, and two are only partially conforming (length/2, between/3). Are there difficulties to implement them in Ciao? Does, e.g., call_nth/2 cause problems? So far there are six implementations that support it directly (GNU, Ichiban, Scryer, SWI, Trealla,YAP), with a further two (SICStus, ECLiPSe) at least having some implementation.