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International Standards Organization Math Document Type Definition Formula Graphic Compiler

IP.com Disclosure Number: IPCOM000113317D
Original Publication Date: 1994-Aug-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 89K

Publishing Venue

IBM

Related People

Miller, WF: AUTHOR

Abstract

A method is described for the handling of Standard Generalized Markup Language (SGML) International Standards Organization Math tags into a formula graphic that can be displayed on a workstation.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

International Standards Organization Math Document Type Definition
Formula Graphic Compiler

      A method is described for the handling of Standard Generalized
Markup Language (SGML) International Standards Organization Math tags
into a formula graphic that can be displayed on a workstation.

      The formula compiler receives an address of a buffer which
contains an SGML definition of a math formula.  This information is
parsed and validated as conforming to the ISO Math DTD.  The formula
compiler digests the SGML, checking for abnormalities as it processes
the information in the buffer.  Error messages, if required are
loaded from a sequential text file and buffered.  Upon return to the
caller, the information passed back is a pointer to error messages
that have been chained together as well as character location of the
error in the input buffer.  Included in the information is a pointer
to a file name that contains the PM graphics metafile.

      The formatter receives notification from the SGML parser that a
formula start tag has been recognized.  This recognition notification
includes the tag element and entities.  At this time the formatter
parses off the element and matches it to a table of element names
which have been constructed from the ISO Math DTD and ISO 8879-1986
Greek Letters, monotonicho Greek letters, numeric and special
symbols, general publishing symbols, general technical symbols, Greek
symbols, alternate Greek symbols, ordinary math symbols, binary math
symbols, relation math symbols, negated math symbols, and delimiters.
This list of approximately 529 elements will have the element name in
column one, the correlating font name in column two, and the system
font id in column three.

      After successful matching of element to font (no match creates
an error message with element name and other contextual data) the
attributes are stored for each element.  This information is stored
in a fast search list (binary or linked-list) and a call is made to
the system font code to get the font metrics.  The metrics are stored
in the element attribute list (X-Min, X-Max, Y- Min,Y-Max), as well
as the element's position in the formula SGML description.  This is
followed by adding the element X-Max, Y-Max to the cumulative X and Y
accumulators, which will ultimately be used to set the viewport of
the formula graphic picture.

      This processing repeats for each tag element...