Compatibility layer for different Prolog implementation -

which best way handle compatibility between 2 different prolog interpreters? i've read question , answers i'm looking methodology coping differently defined predicates (ie delete in swi not variable wise, while under yap is) , newly introduced predicates (ie remove_duplicates not present in library(lists) in swi).

at moment i'm writing file containing of predicates redefinitions of course gets 1 of 2 (or more two) compilers yield warning redefinition.

for sake of semplicity can assume prolog implementation i'm interested in swi , yap. nevertheless general can method highly appreciated.

i think iso prolog should common subset reference.

but libraries massive problem. indeed, experienced issue attempting port swi-prolog snippet yap.

... :- use_module(library(assoc)). :- use_module(library(aggregate)). ... 

assoc library implemented differently in these systems, , not able make yap version work (if remember well, gen_assoc((r, c), gridc, char) had different semantic). also, library(aggregate) had problems under yap.

to conditionally compile among these 2 systems, attempted

/*  file:    prolog_impl.pl     author:  carlo,,,     created: jan 26 2013     purpose: handle swi/yap portability issue */  :- module(prolog_impl, [swi/0, yap/0, prolog_impl/1]).  swi :- prolog_impl(swi). yap :- prolog_impl(yap).  prolog_impl(k) :-     f =.. [k,_,_,_,_],     current_prolog_flag(version_data, f). 

but of course i'm not satisfied this. hope question bring answer problem.