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, 5 insertions, 1 deletions

diff --git a/struct.c b/struct.c
index 5f614af2..943cc393 100644
--- a/struct.c
+++ b/struct.c
@@ -1410,6 +1410,7 @@ static void struct_inst_print(val obj, val out, val pretty,
   val save_mode = test_set_indent_mode(out, num_fast(indent_off),
                                        num_fast(indent_data));
   val save_indent, iter, once;
+  int force_br = 0;
   int compat = opt_compat && opt_compat <= 154;
 
   if (!compat || pretty) {
@@ -1433,7 +1434,8 @@ static void struct_inst_print(val obj, val out, val pretty,
         put_char(chr(' '), out);
         once = nil;
       } else {
-        width_check(out, chr(' '));
+        if (width_check(out, chr(' ')))
+          force_br = 1;
       }
       obj_print_impl(sym, out, pretty, ctx);
       put_char(chr(' '), out);
@@ -1441,6 +1443,8 @@ static void struct_inst_print(val obj, val out, val pretty,
     }
   }
   put_char(chr(')'), out);
+  if (force_br)
+    force_break(out);
   set_indent_mode(out, save_mode);
   set_indent(out, save_indent);
 }