From: stabet@attbi.com
Date: 06/03/03
Hi all,
attached, please find an updated draft for the built-ins.
Regards,
Said
RuleML and DAML Rules Built-ins
DRAFT 2
Said Tabet, Benjamin Grosof and Harold Boley
06/03/2003
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.
Next steps:
- We could define these built-ins in terms of sensors and effectors (as defined by Benjamin)
I suggest we go beyond this classification and exercise the use of OWL to define a Taxonomy
of the built-ins we are considering. Some built-ins could be derived from base ones and
defined by the user ("user-defined built-ins")
- We can also think in terms of "Primitive" and "Derived" built-ins.
- Another important item: using URI references to uniquely address each built-in. We need to
agree on a way to construct these references (see XML schema Datatypes, use of namespaces).
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 = (may not be required in our first version)
3.2 Increment ++
3.3 Decrement --
3.4 Power **
3.5 Abs (absolute value)
3.6 Min
3.7 Max
3.8 Mod (remainder from doing a div)
3.9 bitAnd Performs the bitwise AND on its integer arguments
3.10 bitNot Performs the bitwise NOT on its integer argument
3.11 bitOr Performs the bitwise OR on its integer arguments
3.12 log returns the logarithm base e of its only argument
3.13 log10 returns the logarithm base 10 of its only argument
3.14 random returns a pseudo random integer between 0 and a max value Int32(?)
3.15 round
3.16 sqrt returns the square root of its only argument
4. Data Types
--------------
Our approach is to integrate XML Part 2, Data Types:
http://www.w3.org/TR/xmlschema-2/
We need some examples of the types of built-ins we would use with these data types.
Is that enough?
Example: Duration (as pointed by Sandro on 5/29/03) can be used with comparison and other
built-ins such as calculation.
5. String built-ins:
-----------------
5.1 strLength returns the length of a given string in characters
5.2 strCat string concatenation
5.3 strCompare compares 2 strings
5.4 strIndex returns the position of the first argument within the second argument
5.5 isString returns TRUE if the argument is a string, FALSE otherwise
The same functionality may be obtaind by a test on the class String
5.6 subString returns a substring from a string argument given two 1-based indices
5.7 strUpcase returns the given string argument in Uppercase
5.8 str-lowcase retrns the given string argument in lowercase
5.9 str-startswith returns TRUE if the first string starts with the provided 2nd string
6. URI and 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
9.1 document returns an XML or RDF document given a URI
9.2 serialize serialize an object into a file (XML, RDF, OWL, other format, etc.)
9.3 deserialize deserialize a document (XML, RDF, OWL, etc.) into an object
7. Control and debugging built-ins:
-----------------------------------
NOTE:
These may be considered in an API outside of the scope of our built-ins hierarchy.
However, many implementations in Prolog and production systems consider them as 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
-------------------------------------------------
Objects can be viewed as documents and therefore apply the same built-ins as what we use for URIs and
web documents. A URI can be used as an object identifier.
Any feedback?
9. Built-ins for modules handling
---------------------------------
9.1 setModule set the current module to the module provided as an argument
9.2 getModule returns the current module in focus
9.3 listModules returns a list of declared modules
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