portray/1 hook:- multifile user:portray/1.
user:portray(+Term)
A way for the user to over-ride the default behavior of print/1.
term
If user:portray/1 is defined, then the predicates listed below
performing term output will call it on the term itself and on every
non-variable subterm T. If user:portray/1 succeeds, then it
is assumed to have written T. If it fails, then the calling predicate
will write the principal functor of T and treat the arguments of T
recursively.
Note that on lists ([_|_]), user:portray/1 will be
called on the whole list to user:portray/1 and, if that call
fails, on each list element, but not on every suffix of the list.
Note that a variable written from within user:portray/1 may be
written with a different name than that used by the surrounding write
predicate.
The affected predicates are:
print/[1,2]write_term/[2,3]when used with the option portrayed(true)
controlled by the debugger_print_options Prolog flag,
whose value by default includes portrayed(true)
controlled by the toplevel_print_options Prolog flag,
whose value by default includes portrayed(true)
Exceptions are treated as failures, except an error message is also printed.