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portray_clause/[1,2]
portray_clause(+Clause)
portray_clause(+Stream, +Clause)
Writes Clause to the current output stream. Used by
listing/[0,1]
.
stream_object, must be ground
A valid open Prolog stream, defaults to the current output stream.
term
The operation used by listing/[0,1]
. Clause is written
to Stream, in exactly the format in which listing/[0,1]
would have written it, including a terminating full stop.
If you want to print a clause, then this is almost certainly the
command you want. By design, none of the other term output
commands puts a full stop after the written term.
If you are writing a file of facts to be loaded by
the Load Predicates, then use portray_clause/[1,2]
, which attempts
to ensure that the clauses it writes out can be read in again as clauses.
The output format used by portray_clause/[1,2]
and listing/[0,1]
has
been carefully designed to be clear. We recommend that you use a
similar style. In particular, never put a semicolon
(disjunction symbol) at the end of a line in Prolog.
Stream errors (see ref-iou-sfh-est).
| ?- portray_clause((X:- a -> b ; c)). _ :- ( a -> b ; c ).
| ?- portray_clause((X:- a -> (b -> c ; d ; e); f)). _ :- ( a -> ( b -> c ; d ; e ) ; f ).
| ?- portray_clause((a:-b)). a :- b.
| ?- portray_clause((a:-b,c)). a :- b, c.
| ?- portray_clause((a:-(b,!,c))). a :- b, !, c.
listing/[0,1]
, ref-iou-tou.