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Description / Abstract:
Computer-Aided Software Engineering (CASE) tools are used to
describe the behavior of software using a variety of different
design notations. These may be graphical or textual in nature, or
they may be a combination. This standard provides a reference model
of fundamental software concepts that form the “building blocks”
for a number of these commonly used notations. This standard also
includes a textual language, the Semantic Transfer Language (STL),
for representing software application behavior descriptions. A
software behavior description consists of a collection of sentences
that conform to the formal syntax of the STL and that are to be
interpreted in terms of the software concepts defined in this
standard. The STL syntax is designed to be computer-parsable, while
remaining easy for users to read and write. This reference model
and transfer syntax may be used for directly recording, storing,
and analyzing a software behavior description, as well as for
transferring elements of a software behavior description between
CASE tools.
This standard excludes the structural descriptions of software
product designs or implementations, and it does not provide a
traceable decomposition of software into programs, modules,
subroutines, or objects. However, it does provide the
means to describe the functions and behavior of a program, module,
subroutine, or object.
This standard focuses on the semantics of information concerning
software behavior, not on graphical representations for that
information. Graphical information is not important when
communicating among tools that do not need to reproduce the same
drawing. However, the STL defined in this standard does include
references to images or drawings of graphical symbols that may be
used to indicate correspondences between graphical and textual
representations of the same software concepts.
Purpose
The purpose of this standard is to specify a common set of
modeling concepts based on those found in commercial CASE tools for
describing the operational behavior of a software product. This
standard establishes a uniform, integrated model of software
concepts related to software functionality. It also provides a
textual syntax for expressing the common properties (attributes and
relationships) of those concepts as they have been used to model
software behavior. The 1175.3 exchange syntax is both
machineprocessable and human-readable.
As an alternative to establishing direct tool–tool mappings as
the basis for information sharing among CASE tools, this standard
identifies a common set of "tool-neutral" modeling concepts. By
mapping their internal data into the common STL syntax provided by
this standard, and by exchanging data files constructed using the
STL, it becomes possible for two different CASE tools to reliably
exchange descriptions of a subject software application. As each
tool can map its own meta-model constructs against the standard
1175.3 software behavior concepts, it is not necessary for any one
tool to understand the internal structures of another tool. This
also means that a number of tools can exchange descriptions on the
basis of one set of concept mappings per tool, a substantial
reduction of effort from the pairwise mapping approach.
In addition to tool–tool information exchange applications, the
STL has also been found to be useful for design reviews, a form of
tool-user interconnection. Because the STL is straightforward to
write, and is much like everyday English sentences, it is also
possible to employ the STL for user–user and user–tool information
exchange applications.
This standard incorporates and extends the material in Part 3 of
IEEE Std 1175TM-1991 [B5].1 For backward
compatibility, this standard does not change any of the syntax or
conformance aspects of the STL as defined in Part 3 of IEEE Std
1175-1991 [B5].2 The primary emphasis for this revision
has been to improve the clarity and usability of the material for
its original intended purposes, rather than to revise the content
or otherwise update it to incorporate and represent the software
methodology developments of the 1990s.
1The numbers in brackets correspond to those of the
bibliography in Annex F.
2However, additional syntax has been added to provide
a standardized form for conditional expressions. These were left as
a userdefined item in IEEE Std 1175-1991 [B5].