Basically parse_command() is a piffed up sscanf operating on word basis. It works similar to sscanf in that it takes a pattern and a variable set of destination arguments. It is together with sscanf the only efun to use pass by reference for other variables than arrays.

To make the efun usefull it must have a certain support from the mudlib, there is a set of functions that it needs to call to get relevant information before it can parse in a sensible manner.

In earlier versions it used the normal id() lfun in the LPC objects to find out if a given object was identified by a certain string. This was highly inefficient as it could result in hundreds or maybe thousands of calls when very long commands were parsed. The new version relies on the LPC objects to give it three lists of 'names'.

       1 - The normal singular names.
       2 - The plural forms of the names.
       3 - The acknowledged adjectives of the object.

These are fetched by calls to the functions:

       1 - string *parse_command_id_list();
       2 - string *parse_command_plural_id_list();
       3 - string *parse_command_adjectiv_id_list();

The only really needed list is the first. If the second does not exist than the efun will try to create one from the singluar list. For grammatical reasons it does not always succeed in a perfect way. This is especially true when the 'names' are not single words but phrases.

The third is very nice to have because it makes constructs like 'get all the little blue ones' possible.

Apart from these functions that should exist in all objects, and which are therefore best put in /std/object.c there is also a set of functions needed in /secure/master.c These are not absolutely necessary but they give extra power to the efun.

Basically these /secure/master.c lfuns are there to give default values for the lists of names fetched from each object.

The names in these lists are applicable to any and all objects, the first three are identical to the lfun's in the objects:

string *parse_command_id_list() - Would normally return: ({ "one", "thing" })

string *parse_command_plural_id_list() - Would normally return: ({ "ones", "things", "them" })

string *parse_command_adjectiv_id_list() - Would normally return ({ "iffish" })

The last two are the default list of the prepositions and a single so called 'all' word.

string *parse_command_prepos_list() - Would normally return: ({ "in", "on", "under" })

string parse_command_all_word() - Would normally return: "all"

The function returns 1 if 'command' is considered to have matched 'pattern'. The 'env' or 'oblist' parameter either holds an object or a list of objects. If it holds a single object than a list of objects are automatically created by adding the deep_inventory of the object, ie this is identical:

parse_command(cmd, environment(), pattern, arg)

and

parse_command(cmd, ({ environment() }) + deep_inventory(environment()), pattern, arg)

'pattern' is a list of words and formats:

	Example string = " 'get' / 'take' %i "
	Syntax:
		'word' 		obligatory text
		[word]		optional text
		/		Alternative marker
		%o		Single item, object
		%l		Living objects
		%s		Any text
		%w              Any word
		%p		One of a list (prepositions)
		%i		Any items
		%d              Number 0- or tx(0-99)

The 'arg' list is zero or more arguments. These are the result variables as in sscanf. Note that one variable is needed for each %_

	The return types of different %_ is:
		%o	Returns an object
		%s	Returns a string of words
		%w      Returns a string of one word
		%p	Can on entry hold a list of word in array
			or an empty variable
			Returns:
			   if empty variable: a string
			   if array: array[0]=matched word
		%i	Returns a special array on the form:
			[0] = (int) +(wanted) -(order) 0(all)
			[1..n] (object) Objectpointers	
		%l	Returns a special array on the form:
			[0] = (int) +(wanted) -(order) 0(all)
			[1..n] (object) Objectpointers
			                These are only living objects.
		%d      Returns a number

The only types of % that uses all the loaded information from the objects are %i and %l. These are in fact identical except that %l filters out all nonliving objects from the list of objects before trying to parse.

The return values of %i and %l is also the most complex. They return an array consisting of first a number and then all possible objects matching. As the typical string matched by %i/%l looks like: 'three red roses', 'all nasty bugs' or 'second blue sword' the number indicates which of these numerical constructs was matched:

         if numeral >0 then three, four, five etc were matched
         if numeral <0 then second, twentyfirst etc were matched
         if numeral==0 then 'all' or a generic plural form such as 'apples'
                            were matched.

NOTE! The efun makes no semantic implication on the given numeral. It does not matter if 'all apples' or 'second apple' is given. A %i will return ALL possible objects matching in the array. It is up to the caller to decide what 'second' means in a given context.

Also when given an object and not an explicit array of objects the entire recursive inventory of the given object is searched. It is up to the caller to decide which of the objects are actually visible meaning that 'second' might not at all mean the second object in the returned array of objects.

EXAMPLE:

	 if (parse_command("spray car",environment(this_player()),
        	              " 'spray' / 'paint' [paint] %i ",items))  
	 {	
	    /*
	      If the pattern matched then items holds a return array as
	      described under 'destargs' %i above.
     	    */
	 }

FRIENDLY ADVICE Don't use it.