xo_open_instance(3) [freebsd man page]

LIBXO(3)						   BSD Library Functions Manual 						  LIBXO(3)

NAME

     xo_emit -- emit formatted output based on format string and arguments

LIBRARY

     library ``libxo''

SYNOPSIS

     #include <libxo/xo.h>
LIBXO(3)						   BSD Library Functions Manual 						  LIBXO(3)

NAME

     xo_open_list
     xo_open_list_h
     xo_open_list_hd
     xo_open_list_d
     xo_open_instance
     xo_open_instance_h
     xo_open_instance_hd
     xo_open_instance_d
     xo_close_instance
     xo_close_instance_h
     xo_close_instance_hd
     xo_close_instance_d
     xo_close_list
     xo_close_list_h
     xo_close_list_hd
     xo_close_list_d -- open and close lists and instances

LIBRARY

     library ``libxo''

SYNOPSIS

     int
     xo_open_list_h(xo_handle_t *xop, const char *name);

     int
     xo_open_list(const char *name);

     int
     xo_open_list_hd(xo_handle_t *xop, const char *name);

     int
     xo_open_list_d(const char *name);

     int
     xo_open_instance_h(xo_handle_t *xop, const char *name);

     int
     xo_open_instance(const char *name);

     int
     xo_open_instance_hd(xo_handle_t *xop, const char *name);

     int
     xo_open_instance_d(const char *name);

     int
     xo_close_instance_h(xo_handle_t *xop, const char *name);

     int
     xo_close_instance(const char *name);

     int
     xo_close_instance_hd(xo_handle_t *xop);

     int
     xo_close_instance_d(void);

     int
     xo_close_list_h(xo_handle_t *xop, const char *name);

     int
     xo_close_list(const char *name);

     int
     xo_close_list_hd(xo_handle_t *xop);

     int
     xo_close_list_d(void);

DESCRIPTION

     Lists are sequences of instances of homogeneous data objects.  Two distinct levels of calls are needed to represent them in our output
     styles.  Calls must be made to open and close a list, and for each instance of data in that list, calls must be make to open and close that
     instance.

     The name given to all calls must be identical, and it is strongly suggested that the name be singular, not plural, as a matter of style and
     usage expectations.

     A list is a set of one or more instances that appear under the same parent.  The instances contain details about a specific object.  One can
     think of instances as objects or records.	A call is needed to open and close the list, while a distinct call is needed to open and close
     each instance of the list:
	       xo_open_list("item");

	       for (ip = list; ip->i_title; ip++) {
		   xo_open_instance("item");
		   xo_emit("{L:Item} '{:name/%s}':0, ip->i_title);
		   xo_close_instance("item");
	       }

	       xo_close_list("item");
     Getting the list and instance calls correct is critical to the proper generation of XML and JSON data.

	       EXAMPLE:
		   xo_open_list("user");
		   for (i = 0; i < num_users; i++) {
		       xo_open_instance("user");
		       xo_emit("{k:name}:{:uid/%u}:{:gid/%u}:{:home}0,
			       pw[i].pw_name, pw[i].pw_uid,
			       pw[i].pw_gid, pw[i].pw_dir);
		       xo_close_instance("user");
		   }
		   xo_close_list("user");
	       TEXT:
		   phil:1001:1001:/home/phil
		   pallavi:1002:1002:/home/pallavi
	       XML:
		   <user>
		       <name>phil</name>
		       <uid>1001</uid>
		       <gid>1001</gid>
		       <home>/home/phil</home>
		   </user>
		   <user>
		       <name>pallavi</name>
		       <uid>1002</uid>
		       <gid>1002</gid>
		       <home>/home/pallavi</home>
		   </user>
	       JSON:
		   user: [
		       {
			   "name": "phil",
			   "uid": 1001,
			   "gid": 1001,
			   "home": "/home/phil",
		       },
		       {
			   "name": "pallavi",
			   "uid": 1002,
			   "gid": 1002,
			   "home": "/home/pallavi",
		       }
		   ]

LEAF LISTS

     In contrast to a list of instances, a "leaf list" is list of simple values.  To emit a leaf list, call the xo_emit() function using the ""l""
     modifier:
	       for (ip = list; ip->i_title; ip++) {
		   xo_emit("{Lwc:Item}{l:item}0, ip->i_title);
	       }

     The name of the field must match the name of the leaf list.

     In JSON, leaf lists are rendered as arrays of values.  In XML, they are rendered as multiple leaf elements.
	       JSON:
		   "item": "hammer", "nail"
	       XML:
		   <item>hammer</item>
		   <item>nail</item>

ADDITIONAL DOCUMENTATION

     Complete documentation can be found on github:

	   http://juniper.github.io/libxo/libxo-manual.html

     libxo lives on github as:

	   https://github.com/Juniper/libxo

     The latest release of libxo is available at:

	   https://github.com/Juniper/libxo/releases

SEE ALSO

     xo_emit(3)

HISTORY

     The libxo library was added in FreeBSD 11.0.

AUTHOR

     Phil Shafer

BSD
								 December 4, 2014							       BSD