In December 2007, the Object Management Group (OMG) approved the "Semantics of Business Vocabulary and Business Rules" (SBVR) to become an official specification of the OMG.  Version 1 (SBVR 1.0) was published January 2008; Versions 2 (SBVR 1.1) & 3 (SBVR 1.2) were published in 2013).[1]  SBVR is the first OMG standard for concept models and business rules. SBVR is a highly-structured set of fundamental concepts, not a syntax for rule representation.  In part, this approach is necessary for multi-lingual support; in part, it is to ensure support for a variety of representational schemes.  One such scheme is RuleSpeak®, which played a central role in the shaping and proofing of the standard itself.  The material that follows is extracted from the RuleSpeak Annex of SBVR.

RuleSpeak^® is an existing, well-documented^[2] business rule notation developed by Business Rule Solutions, LLC (BRS), which has been used with business people in actual practice in large-scale projects since the second half of the 1990s. 

A companion column^[3] in this issue of the Journal introduced two styles of business rule statement:  prefixed rule keyword style and embedded (mixfix) rule keyword style.  That article detailed a business rule notation within SBVR Structured English that features prefixing rule keywords onto appropriate propositions.  RuleSpeak can also use the expression forms of SBVR Structured English (term, name, and verb) but embeds equivalent keywords within the propositions themselves (mixfix).  As the companion article explained, more than one notation for expressing business rules is possible using SBVR Structured English.  (This is probably also true for other notations compliant with SBVR.)  Regardless of how expressed, equivalent semantics can be captured^[4] and formally represented as logical formulations.

Expressions in RuleSpeak

RuleSpeak builds on the same expression forms described in the SBVR Structured English Annex of SBVR (Annex A), with the minor difference that distinct keywords are used for the Modal Operations related to business rules.  The following section presents the RuleSpeak alternative rule keywords for Rules and Advices.^[5]

Modal Operations in RuleSpeak

Behavioral

Modality claim type	Statement form	SBVR Structured English keywords	RuleSpeak keywords
obligation claim	obligation statement'	it is obligatory that p	r must s
obligation claim embedding a logical negation	prohibition statement	it is prohibited that p	r must not s
	restricted permission statement	it is permitted that p only if q	r may s only t
permissibility claim	unrestricted permission statement	it is permitted that p	r may s
			r need not s

Definitional

necessity claim	necessity statement	it is necessary that p	r always s
necessity claim embedding a logical negation	impossibility statement	it is impossible that p	r never s
	restricted possibility statement	it is possible that p only if q	r can s only t
possibility claim	unrestricted possibility statement	it is possible that p	r sometimes s
			r can s

Notes:

• p and q, and r, s, and t, are all parts of the same proposition, say u.
  
  
• In a permissibility claim or a possibility claim, the 'only' is always followed immediately by one of the following:
  1. an 'if' (yielding 'only if').
  2. a preposition.

An example of a business rule statement using the 'only [preposition]' form is the following:

A spot discount for a rental may be given only by a branch manager.

Example in RuleSpeak

Each rental car must be owned by exactly one branch.

The example above includes three keywords, two terms (designations for noun concepts), and one verb symbol (of a verb concept's wording), as illustrated below.

As noted above, every Behavioral Business Rule or Advice can be stated by using one of the following embedded keywords.

must	or  should	rule keyword
must not	or  should not	rule keyword
only	often as in  only if	rule keyword
may	or  need not	advice keyword

Every Definitional Rule or Advice can be stated by using one of the following embedded keywords.

always		rule keyword
never		rule keyword
can ... only	often as in  can ... only if	rule keyword
sometimes	or  not always or  can	advice keyword

Special-purpose keywords for indicating specific kinds of Definitional Rules include the following.  In these forms, 'always' is assumed implicit.

is to be considered		for derivation or inference
is to be computed as		for computation
is to be fixed at [number]	or is to be [number]	for establishing constants

Basic RuleSpeak Guidelines

Among the most basic usage rules and guidelines of RuleSpeak are the following.  (Note that these usage rules and advices are given using proper RuleSpeak notation.)

References

[1]  Semantics of Business Vocabulary and Business Rules (SBVR), v1.2.  Object Management Group (Nov. 2013).  SBVR 1.2 and its supporting files are available at http://www.omg.org/spec/SBVR/1.2/  The most-current version can always be found at http://www.omg.org/spec/SBVR/ 

[2]  Ronald G. Ross.  Principles of the Business Rule Approach.  Boston, MA:  Addison-Wesley, 2003, Chapters 8-12.  Versions of RuleSpeak have been available on the Business Rule Solutions, LLC website (www.BRSolutions.com/b_principles.php) since the late 1990s.  Public seminars have taught the syntax to thousands of professionals starting in 1996 (www.AttainingEdge.com).  The original research commenced in 1985, and was published in The Business Rule Book, 1994 (www.BRSolutions.com).

[3]  SBVR Insider, "Notations for Business Rule Expression," Business Rules Journal, Vol. 7, No. 4 (Apr. 2006), revised (Oct. 2013), URL:  http://www.BRCommunity.com/a2006/b286.html

[4]  For a business-oriented, SBVR-compliant approach, see:  Ronald G. Ross.  Business Rule Concepts:  Getting to the Point of Knowledge.  4th ed.:  Business Rule Solutions, LLC, 2013, Chapter 7. (www.BRSolutions.com/b_concepts.php).

[5]  It is important to note that use of these keywords must be in a context that is clearly indicated to be for Rules and Advices only.

[6]  Principles of the Business Rule Approach, p. 130.

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