Computing with text graphic forms occurs when text graphic patterns are used
to direct the processing of other text graphic patterns. The PAM graphics
system was designed for just this kind of computation; PAM stands for PAttern
Manipulating PAM is a generalization of LISP (McCarthy 1960)* from computing
with (textual) symbolic expressions to computing with text graphic forms.
Like LISP, PAM achieves processing power by providing atomic objects, means of
structuring them into complex objects and taking them apart, and equality
tests for objects. Text graphic engines can then be defined, allowing text
editors, text graphic editors, circuit design aids and visual language
processors to all be developed in the same LISP like environment. Examples
discussed in the paper are:
handPAM is an agile environment for the manual manipulation of textgraphic objects (described briefly).writtenPAM provides programmatic manipulation of visual objects. Pattern processing is demonstrated by functions which translate a LISP sexpr to the visual name
shape synonyms of the VennLISP notation system, and then spatially lay it out.writtenPAM also permits definition of pattern evaluating, enabling actual computation with text
graphic forms. An eval function for textgraphic objects is given which can execute VennLISP expressions.
An experimental version of the PAM system has been implemented in MACLISP at the Stanford Artificial Intelligence Lab.
Definition of the member function in VennLISP
This paper was published in the
proceedings of the first ever LISP Conference at Stanford University, August 1980.
* McCarthy, John, "Recursive functions of symbolic expressions and their computation by machine", Comm. ACM, 1960, vol. 3, no.4.
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