json: new special var *print-json-type*.

This variable controls whether we emit the "__type" key
for structures.

* lib.c (out_json_rec): React to the new variable, via
the flag in the json_opts structure: include the "__type" key
only if it is requested.
(out_json, put_json): Initialize the type flag in the josn_opts
according to the *print-json-type* dynamic variable.

* stream.c (print_json_type_s): New symbol variable.
(stream_init): print_json_type_s initialized, and
corresponding special variable registered, with intial value t.

* stream.h (struct json_opts): New bitfield member, type.
(print_json_type_s): Declared.

* txr.1: Documented.

1 files changed, 2 insertions, 1 deletions

diff --git a/stream.c b/stream.c
index 7114a123..58d0804f 100644
--- a/stream.c
+++ b/stream.c
@@ -95,7 +95,7 @@ val get_error_s, get_error_str_s, clear_error_s, get_fd_s;
 
 val print_flo_precision_s, print_flo_digits_s, print_flo_format_s;
 val pprint_flo_format_s, print_base_s, print_circle_s;
-val print_json_format_s;
+val print_json_format_s, print_json_type_s;
 
 val from_start_k, from_current_k, from_end_k;
 val real_time_k, name_k, addr_k, fd_k, byte_oriented_k;
@@ -5587,6 +5587,7 @@ void stream_init(void)
           num_fast(10));
   reg_var(print_circle_s = intern(lit("*print-circle*"), user_package), nil);
   reg_var(print_json_format_s = intern(lit("*print-json-format*"), user_package), nil);
+  reg_var(print_json_type_s = intern(lit("*print-json-type*"), user_package), t);
 
 #if HAVE_ISATTY
   if (isatty(fileno(stdin)) == 1) {