Building Visual Language Parsers

Richard Helm, Kim Marriott and Martin Odersky
ACM SIGCHI Conference on Human Factors in Computing Systems
April 1991.

Notepad computers promise a new input paradigm where users communicate
with computers in visual languages composed of handwritten text and
diagrams.  A key problem to be solved before such an interface can be
realized is the efficient and accurate recognition (or {\em parsing})
of handwritten input.  We present techniques for building visual
language parsers based on a new formalism, constrained set grammars.
Constrained set grammars provide a high-level and declarative
specification of visual languages and support the automatic generation
of efficient parsers.  These techniques have been used to build
parsers for several representative visual languages.