printer: improve object formatting.

There is an issue with the printer in that it produces
output whereby objects continue on the same line after
a multi-line object, e.g:

   (foo (foobly bar
         xyzzy quux) (oops same
                      line))

rather than:

   (foo (foobly bar
         xyzzy quux)
        (oops same line))

There is a simple fix for this: set a flag to force
a line break on the next width-check operation whenever
an object has been broken into multiple lines.

width-check can return a Boolean indication whether
it generated a line break, and so aggregate object
printing routines can tell whether their object
has been broken into lines, and set the flag.

* stream.h (struct strm_base): New member, force_break.
(force_break): Declared.

* stream.c (strm_base_init): Extent initializer to cover
force_break flag.
(put_string, put_char): Clear the force_break flag whenever
we hit column zero.
(width_check): If indent mode is on, and force_break is
true, generate a break. Clear force_break.
(force_break): New function.
(stream_init): Register force-break intrinsic.

* buf.c (buf_print): Set the force break flag if the buffer
was broken into multiple lines.

* hash.c (hash_print_op): Set the force break flag if the
hash was broken into multiple lines.

* lib.c (obj_print_impl): Same logic for lists.

* struct.c (struct_inst_print): Same logic for structs.

* tests/009/json.expected, tests/011/macros-2.expected,
tests/012/struct.tl, tests/017/glob-zarray.expected:
Update expected textual output to reflect new formatting.

1 files changed, 2 insertions, 0 deletions

diff --git a/stream.h b/stream.h
index bb581371..12750639 100644
--- a/stream.h
+++ b/stream.h
@@ -49,6 +49,7 @@ struct strm_base {
   cnum code_width;
   cnum indent_chars;
   cnum column;
+  unsigned force_break;
   struct strm_ctx *ctx;
 };
 
@@ -209,6 +210,7 @@ val get_indent(val stream);
 val set_indent(val stream, val indent);
 val inc_indent(val stream, val delta);
 val width_check(val stream, val alt);
+val force_break(val stream);
 struct strm_ctx *get_set_ctx(val stream, struct strm_ctx *);
 struct strm_ctx *get_ctx(val stream);
 val get_string(val stream, val nchars, val close_after_p);