STEP README: SGML DTDs for STEP README file for SGML subdirectory on SOLIS This README file assumes that the reader has a working knowledge of both STEP and SGML. For more information in either of these or related areas, see documents in "References" section below. SGML DTDs for STEP ------------------- As part of the Application Protocol Development Environment (APDE), NIST is developing SGML document type definitions (DTDs) for STEP (ISO 10303) documents. These DTDs are being written according to the Supplementary Directives for the Drafting and Presentation of STEP documents and thus will support the development of STEP documents which are consistent and structurally correct. The DTDs will also be used along with the corresponding tagged SGML documents to facilitate structure-based querying, browsing, and retrieval of STEP documents. Currently, a DTD for STEP Integrated Resources and two DTDs for STEP Application Protocols have been developed at NIST. All of these DTDs are now available electronically through SOLIS and are intended for general use in the STEP community. Using these DTDs, users may develop or convert an existing document into an SGML-tagged STEP document or access existing SGML documents which conform to these DTDs. The DTDs for STEP Application Protocols consist of two separate specifications. One specification is intended for publishing purposes and represents all boilerplate and generated components of APs. The other specification is intended for editing purposes and only represents that information which must be provided by the user and any supporting text that is needed to understand the user-specific information while editing. The first specification is referred to as the publishing AP DTD and is more similar in structure to the DTD for IRs. The second specification is referred to as the editing AP DTD. The DTD for STEP Integrated Resources is now being used to develop and convert documents into SGML. Thus far, STEP parts 43, 44, and 101 have all been converted to SGML using this DTD (see "SGML-tagged STEP parts" below). The DTDs for STEP Applications Protocols were recently completed therefore no APs have yet been fully tagged using this DTD. However, AP 203 was tagged using an earlier version of the AP DTD and should require little effort to convert this document into an instance conforming to the latest AP DTD. NIST plans to continue tagging STEP parts and will provide them on SOLIS and in an information base which will contain these and other documents related to STEP. Accessing the common DTD constructs and entity sets --------------------------------------------------- Many DTD constructs are shared by more than one of the STEP DTDs. The elements which are shared by multiple DTDs are clustered into logical groupings, each of which is stored in a separate file. Additionally, the public entity sets which are provided by ISO are each stored in a separate file for access by the DTDs. Each file containing a logical grouping of shared elements or an ISO entity set is referenced into the STEP DTDs via an SGML parameter entity. All parameters entities are defined in a file called parament.dtd which the user must update to point to the system-specific location of each referenced file. The user should also update the DTD to point to the system-specific location of the parament.dtd file. The current location of these files on SOLIS is /pub/step/sgml/dtds/common/ SGML-tagged STEP parts ----------------------- Each STEP part subdirectory in the private ftp area and in the public area on SOLIS for which an SGML tagged version of the part is available contains a subdirectory called sgml. The files in each sgml subdirectory comprise a NIST-developed SGML document instance which conforms to the corresponding DTD. The files in the sgml subdirectories are broken up into a master SGML file and one or more other sub-files which contain the graphics or figures referred to in the master SGML file. The format of the sub-files are indicated by their filename extensions. The document instance in each sgml subdirectory was converted to SGML from the original format of the part as stored in the parent directory of the subdirectory. All document instances were successfully validated using psgml and sgmls. Using the NIST-developed DTDs to Develop or Access a STEP part --------------------------------------------------------------- In order to use the DTDs to develop or access an SGML STEP part, the user should minimally be equipped with a DTD parser which will parse the DTD and in some cases, produce a compiled version of the DTD to be used by an SGML-based application. The user will also require a document instance parser to validate the document instance against the corresponding DTD. Several commercial and public domain DTD parsers are available either as a stand-alone tool or as part of a stand-alone tool. (For more information on available DTD parsers, see "For more information" below.) The STEP DTDs have been validated using sgmls, a public domain DTD and SGML document instance parser. The DTDs have also been validated with the Author/Editor DTD "rules builder" (mkrls) program. If you are using sgmls, psgml (an emacs mode for editing SGML documents), or Author/Editor to parse this DTD, the following special instructions apply: Using the DTDs with sgmls or psgml ---------------------------------- The following table describes the necessary modifications to the sgmls source code: File Description --------------------------------------------------------------------- sgmldecl.c Change first value after #define REFCAPSET from 35000 to 200000 to handle size of DTD. This first value corresponds with the TOTALCAP parameter in SGML. entity.h Change REFNAMELEN from 8 to 32 to handle legnth of element names. entity.h Change REFLITLEN from 240 to 800 to handle legnth of entity definitions. After making changes to the sgmls source code, run "make" in the directory in which the source code is located to generate a new sgmls executable. The current DTDs do not contain a DOCTYPE statement at the beginning of the specification. This was done to faciliate parsing the DTDs with other SGML tools we are using at NIST for the SGML environment for STEP. To use sgmls to parse our DTDs, the following changes to the DTDs should be incorporated: File Description --------------------------------------------------------------------- IR DTD Add the following lines to the top of the file: AP DTDs Add the following lines to the top of the file: Note that future versions of the DTDs will contain the DOCTYPE statement and the above changes will no longer apply. Using the DTDs with Author/Editor mkrls program ----------------------------------------------- Change the default SGML declaration file provided by Author/Editor (sgml.dec) as follows: Add parameter NAMELEN to QUANTITY SGMLREF section. Set NAMELEN to 32 to increase the permissible name lengths from 8 to 32. NIST-provided applications based on STEP DTDs ---------------------------------------------- NIST is developing SGML-aware applications which are based on the STEP DTDs. These applications will be provided to selected alpha users and to the STEP community at large in fiscal year 1996. The following applications will be provided: o STEP-customized SGML editor o automated SGML conversion tools o SGML formatter (for translating SGML documents into a publishable format)* o Text database system *The SGML formatter tool can now be used to convert SGML-tagged integrated resources into LaTeX and Postscript. This tool is expected to be released to SOLIS by November 15, 1995. This and other NIST-developed applications will be stored in the /pub/step/nistools directory as they become available. Description of subdirectories in /pub/step/sgml ------------------------------------------------ dtds/ NIST developed DTDs for STEP docs/ supporting documentation for using DTDs Each of these subdirectories and their subdirectories contain readme.txt files which describe their content in detail. For more information -------------------- For more information regarding the STEP DTDs, the tagged document instances, or the NIST-developed applications contact: Lisa Phillips National Institute of Standards and Technology Building 220, Room A127 Gaithersburg, Md 20899 USA telephone: 301-975-5021 fax: 301-869-9017 email: phillips@cme.nist.gov References ---------- Clark, Stephen N, Allison Barnard Feeney, and James E. Fowler, Specifications for an Application Protocol Development Environment, NISTIR 5248, National Institute of Standards and Technology, Gaithersburg, Md., August 1993. Goldfarb, Charles F., The SGML Handbook, Oxford University Press, New York, 1992. International Organization for Standardization, ISO 10303 Industrial Automation Systems and Integration - Product Data Representation and Exchange - Overview and Fundamental Principles, Draft International Standard, ISO TC184/SC4, 1992. Phillips, Lisa, A DTD for STEP Integrated Resources, ISO TC184/SC4 Editing Committee Version 1.0, N43, September 5, 1994. Phillips, Lisa and Joshua Lubell, An SGML Environment for STEP, NISTIR 5547, National Institute of Standards and Technology, Gaithersburg, Md., June, 1994. Shaw, Nigel, Supplementary Directives for the Drafting and Presentation of ISO 10303, Version 1.1, N40, July 10, 1993. Rinaudot, Gaylen, The STEP On-line Information Service. NISTIR 5511, National Institute of Standards and Technology, Gaithersburg, Md., October 1994. *********************************************************************** *********************************************************************** *********************************************************************** Author: Lisa Phillips / phillips@cme.nist.gov / 301-975-5021 Last edited: October 16, 1995