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, 5 insertions, 3 deletions

diff --git a/lib.h b/lib.h
index 9e1405a0..5d620446 100644
--- a/lib.h
+++ b/lib.h
@@ -228,9 +228,11 @@ struct cobj {
   val cls;
 };
 
+struct strm_ctx;
+
 struct cobj_ops {
   val (*equal)(val self, val other);
-  void (*print)(val self, val stream, val pretty);
+  void (*print)(val self, val stream, val pretty, struct strm_ctx *);
   void (*destroy)(val self);
   void (*mark)(val self);
   cnum (*hash)(val self, int *count);
@@ -248,7 +250,7 @@ struct cobj_ops {
  * Default equal is eq
  */
 
-void cobj_print_op(val, val, val);
+void cobj_print_op(val, val, val, struct strm_ctx *);
 void cobj_destroy_stub_op(val);
 void cobj_destroy_free_op(val);
 void cobj_mark_op(val);
@@ -975,7 +977,7 @@ val set_from(val range, val from);
 val set_to(val range, val to);
 val env(void);
 void out_str_char(wchar_t ch, val out, int *semi_flag);
-val obj_print_impl(val obj, val out, val pretty);
+val obj_print_impl(val obj, val out, val pretty, struct strm_ctx *);
 val obj_print(val obj, val stream);
 val obj_pprint(val obj, val stream);
 val tostring(val obj);