Add stream printing context.

This is some infrastructure which will support *print-circle*.

* lib.h (struct strm_ctx): Forward declared.
(struct cobj_ops): Add context parameter to print function
pointer.
(cobj_print_op, obj_print_impl): Add context parameter to
declarations.

* hash.c (hash_print_op): Take context argument and
pass it down in obj_print_impl calls.

* lib.c (cobj_print_op, out_quasi_str): Likewise
(obj_print_impl): Likewise, and also pass to
COBJ print method.
(obj_print, obj_pprint): Pass null pointer
as context argument to obj_print_impl.

* regex.c (regex_print): Take context parameter and ignore it.

* socket.c (dgram_print): Likewise.

* stream.h (struct strm_ctx): New struct type.
(struct strm_base): New ctx member, pointer to struct
strm_ctx.
(stream_print_op): Add context parameter to declaration.
(get_set_ctx, get_ctx): Declared.

* stream.c (strm_base_init): Add null pointer to initializer.
(strm_base_cleanup): Add assertion against context pointer
being non-null: that indicates that some stream operation
installed a context pointer and neglected to restore it to
null before returning, which is bad because context will be
stack allocated.
(stream_print_op, stdio_stream_print, cat_stream_print): Take
context parameter and ignore it.
(get_set_ctx, get_ctx): New functions.

* struct.c (struct_type_print): Take context parameter and
ignore it.
(struct_inst_print): Take context parameter and pass
down to obj_print_impl.

1 files changed, 4 insertions, 2 deletions

diff --git a/regex.c b/regex.c
index 14f89fcc..bd6ed971 100644
--- a/regex.c
+++ b/regex.c
@@ -1373,7 +1373,7 @@ static void regex_mark(val obj)
   gc_mark(regex->source);
 }
 
-static void regex_print(val obj, val stream, val pretty);
+static void regex_print(val obj, val stream, val pretty, struct strm_ctx *);
 
 static struct cobj_ops regex_obj_ops = cobj_ops_init(eq,
                                                      regex_print,
@@ -2308,12 +2308,14 @@ static void print_rec(val exp, val stream, int *semi_flag)
   }
 }
 
-static void regex_print(val obj, val stream, val pretty)
+static void regex_print(val obj, val stream, val pretty, struct strm_ctx *ctx)
 {
   regex_t *regex = coerce(regex_t *, cobj_handle(obj, regex_s));
   int semi_flag = 0;
 
   (void) pretty;
+  (void) ctx;
+
   put_string(lit("#/"), stream);
   print_rec(regex->source, stream, &semi_flag);
   put_char(chr('/'), stream);