RuleML and DAML Rules Built-ins
			DRAFT 1
		
	    Said Tabet, Benjamin Grosof and Harold Boley
			05/27/2003


This document describes a proposed preliminary list of built-ins for RuleML and DAML Rules. The approach we are taking is to focus on an initial set of functions and operators before extending this list to more advanced built-ins dealing with URIs, external APIs and other custom functionality.

We organize the proposed list into subsets of built-ins:

1. Elementary Arithmetic built-ins:
----------------------------
	1.1	Addition:			+
	1.2	Substraction:		-
	1.3	Multiplication:		*
	1.4	Division:			/

2. Comparaison built-ins:
------------------------
	2.1	Greater Than		>
	2.2	Less Than		<
	2.3	Equal			==
	2.4	Less Than or Equal		<=
	2.5	Greater Than or Equal	>=
	2.6	Not Equal			!=

3. More Built-ins:
----------------
	3.1	Assign			=
	3.2	Increment		++
	3.3	Decrement		--
	3.4	Power			**
	3.5	Abs (absolute value)
	3.6	Min
	3.7	Max

4. Data Types
--------------
	Our approach is to integrate XML Part 2, Data Types:
	http://www.w3.org/TR/xmlschema-2/

5. String built-ins:
-----------------
	5.1	str-length	returns the length of a given string in characters
	5.2	str-cat		string concatenation
	5.3	str-compare	compares 2 strings
	5.4	str-index		returns the position of the first argument within the second argument
	5.5	is-String		returns TRUE if the argument is a string, FALSE otherwise
	5.6	sub-string	returns a substring from a string argument given two 1-based indices
	5.7	str-upcase	returns the given string argument in Uppercase
	5.8	str-lowcase	retrns the given string argument in lowercase

6. I/O Streams built-ins:
-----------------------
	6.1	open		Open a file or a stream
	6.2	read		Read from stream or file
	6.3	write		Write to a stream or file
	6.4	close		close file or stream
	6.5	printout		sends unformatted output to a given stream/router
	
7. Control and debugging built-ins:
---------------------------------
	7.1	run		invoke an inference cycle
	7.2	query		run a query
	7.3	halt		halts an inference/query cycle
	7.4	reset		reset the fact base
	7.5	show-facts	returns the list of asserted facts
	7.5	show-rules	returns the list of rules
	7.8	debug		runs in a debug mode: traces all rule firings
	7.9	assert		assert new facts
	7.10	retract		retract facts
	7.11	load-facts	asserts facts loaded from a file
	7.12	load-rules	loads rules from a file
	7.13	evaluate		evaluates a string input as command line input and returns the result
	7.14	clear		clear engine from all its contents: rules, facts, etc.
	
8. External objects and pointers access built-ins
--------------------------------------------
	TBD

9. URIs built-ins
---------------
	TBD