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yap-6.3/packages/RDF/pretty_print.pl
Vitor Santos Costa 8d3b9ad16c RDF package
2010-07-28 11:34:41 +01:00

168 lines
3.4 KiB
Prolog

/* $Id$
Part of SWI-Prolog SGML/XML parser
Author: Jan Wielemaker
E-mail: jan@swi.psy.uva.nl
WWW: http://www.swi.psy.uva.nl/projects/SWI-Prolog/
Copying: LGPL-2. See the file COPYING or http://www.gnu.org
Copyright (C) 1990-2000 SWI, University of Amsterdam. All rights reserved.
*/
:- module(dia_pretty_print,
[ pretty_print/1
]).
:- require([ atom_length/2
, between/3
, forall/2
, is_list/1
, member/2
, memberchk/2
]).
pretty_print(Term) :-
numbervars(Term, 0, _),
pp(Term, 0),
write('.'), nl, fail.
pretty_print(_).
pp(Term, _Indent) :-
atomic(Term), !,
writeq(Term).
pp(Var, _Indent) :-
var(Var), !,
write(Var).
pp(Var, _Indent) :-
Var = '$VAR'(_), !,
print(Var).
pp('$aref'(Name), _Indent) :- !,
write(Name).
pp(Module:Term, Indent) :-
atomic(Module), !,
writeq(Module), write(:),
pp(Term, Indent).
pp([A1 = V1|ArgList], Indent) :- % [] is done by `atomic'!
is_list(ArgList),
forall(member(A, ArgList), A = (_ = _)),
longest_attribute([A1 = V1|ArgList], 0, L), !,
NewIndent is Indent + 2,
( L > 9, Indent < 25, length(ArgList, Args), Args > 1
-> ArgIndent is Indent + 4,
ValGoal = (nl, indent(ArgIndent))
; ArgIndent is Indent + 6 + L,
ValGoal = write(' ')
),
write('[ '),
pp(A1, Indent), term_length(A1, L1),
tab(L-L1), write(' ='), ValGoal,
pp(V1, ArgIndent),
forall(member(A = V, ArgList),
(write(','), nl,
indent(NewIndent),
pp(A, Indent), term_length(A, LA), tab(L-LA),
write(' ='), ValGoal, pp(V, ArgIndent))),
nl,
indent(Indent),
write(']').
pp([H|T], Indent) :-
is_list(T), !,
write('[ '),
NewIndent is Indent + 2,
pp(H, NewIndent),
forall(member(E, T),
(write(','), nl,
indent(NewIndent),
pp(E, NewIndent))),
nl,
indent(Indent),
write(']').
pp(Term, Indent) :-
functor(Term, Name, 2),
current_op(_, Type, Name),
memberchk(Type, [xfx, yfx]), !,
arg(1, Term, A1),
arg(2, Term, A2),
pp(A1, Indent), format(' ~q ', [Name]), pp(A2, Indent).
pp(Term, Indent) :-
functor(Term, Name, _Arity),
atom_length(Name, L),
NewIndent is Indent + L + 1,
format('~q(', Name),
( term_argument_length(Term, AL),
NewIndent + AL < 72
-> Wrap = nowrap
; Wrap = wrap
),
forall(generate_arg(I, Term, Arg),
pparg(I, Arg, Wrap, NewIndent)),
write(')').
generate_arg(ArgN, Term, Arg) :-
functor(Term, _, Arity),
between(1, Arity, ArgN),
arg(ArgN, Term, Arg).
pparg(1, Term, _, Indent) :- !,
pp(Term, Indent).
pparg(_, Term, wrap, Indent) :- !,
write(','), nl,
indent(Indent),
pp(Term, Indent).
pparg(_, Term, _, Indent) :-
write(', '),
pp(Term, Indent).
longest_attribute([], L, L).
longest_attribute([A = _|T], L0, L) :-
term_length(A, AL),
max(L0, AL, L1),
longest_attribute(T, L1, L).
term_length(A, AL) :-
atomic(A), !,
atom_length(A, AL).
term_length(Var, AL) :-
var(Var), !,
AL = 1.
term_length('$VAR'(N), AL) :-
varname(N, L),
length(L, AL).
term_length('$aref'(N), AL) :-
atom_length(N, AL).
term_argument_length(Term, L) :-
term_argument_length(Term, 1, 0, L).
term_argument_length(Term, A, L0, L) :-
arg(A, Term, Arg), !,
term_length(Arg, AL),
L1 is AL + L0,
NA is A + 1,
term_argument_length(Term, NA, L1, L).
term_argument_length(_, _, L, L).
max(A, B, M) :-
( A >= B
-> M = A
; M = B
).
varname(N, [C]) :-
N < 26, !,
C is N + 0'A.
varname(N, [C1, C2]) :-
C1 is N // 26 + 0'A,
C2 is N mod 26 + 0'A.
indent(I) :-
Tabs is I // 8,
forall(between(1, Tabs, _), put(9)),
Spaces is I mod 8,
tab(Spaces).