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The term Term is written on the output stream Stream in a form that ignores
operator declarations and can be read in.
- Stream handle or alias (atom)
- Prolog term.
Used to write the term Term in a form that can be read back independent
of the current operator declarations. Atoms and strings are quoted,
operator declarations are ignored, lists are printed as ./2 structures,
the (stream-specific or global) print_depth flag is not taken into account,
variable attributes are printed, and variables are printed with unique
write_canonical(S,Term) is equivalent to printf(S,"%DMOQv.w", Term)
or write_term(S,Term, [attributes(full),operators(false),quoted(true),
Note that as usual, the output is buffered, so it may need to be flushed
either by closing the stream, by writing again or by using flush/1.
Modes and Determinism
- write_canonical(+, ?) is det
This predicate is sensitive to its module context (tool predicate, see @/2).
- (4) instantiation fault
- Stream is not instantiated.
- (5) type error
- Stream is not an atom or a stream handle.
- (192) illegal stream mode
- Stream is not an output stream.
- (193) illegal stream specification
- Stream is an illegal stream specification.
?- write_canonical(output, 'A'+[a,B]).
+('A', .(a, .(_216, )))
B = B
write_canonical(S, a(b,c)). (Error 4).
write_canonical("string", a(b,c)). (Error 5).
write_canonical(input, X + 2). (Error 192).
write_canonical(atom, X + 2). (Error 193).
write / 1, write / 2, writeq / 1, writeq / 2, write_canonical / 1