From: MATH0022@rmc.ca
Newsgroups: comp.lang.icon
Subject: (1) ICON & OS/2 ? (2) Strings vs. Lists.
Date: 18 Aug 92 17:42:02 GMT
Reply-To: lindsay@rmc.ca
Distribution: inet
Organization: The Internet

(1) Would someone please post some comments, status, considerations or
    availability information about using ICON with OS/2 (as opposed to DOS or to
    DOS + WINDOWS or other multitasker) on '386 or '486 type equipment (either
    the interpreter or a compiler) ?
 
(2) A few months ago, there were a few ruminations on this board about
    processing strings as lists or rather vv.; I'd like to open up and expand
    the subject again.  Plainly there is a logical parallel between a string and
    a list, the differences being (a) that strings (in ICON and other languages
    too) are limited to having characters as components, while lists may have
    elements of any data type or any one other data type, (b) the obvious
    implementations on all the machines that I can think of are quite different,
    and (c) the operations that we tend to impute to lists are quite different
    from those that are usually associated with strings.  But are they still?
    Both strings and lists are linear.  We have been processing at least
    2-dimensional images such as photographs of lunar and planetary surfaces to
    extract hidden detail and display it, and the image processing that I've
    seen bears no obvious relation to our current SNOBOLish concept of patterns
    in a string or list.
 
    Hence there seem to be 2 questions that are still open after several years
    of work: First, can we expand our concept of (linear) pattern so that that
    sort of pattern matching can be extended into 2 or more dimensions, perhaps
    via nearest-neighbour paths in an array, and Second, what new operators are
    needed for 'pattern matching' in 2 or more dimensions or for recognizing
    patterns in lists of numbers e.g., and what do these new operators say about
    linear pattern matching?
 
    The early attempts to try to deal with these 2 questions seem to have gotten
    almost nowhere, and the subject has almost been dropped in favour of
    artificial intelligence and computer vision considerations.  In the early
    1970's, I believe, I heard of a paper entitled 'How to Parse (the picture
    of) a Dog', but I never located it.  In view of our recent advances in image
    analysis, I suggest that another look is in order.
 
--------------------------------------------------------------------------------
 
            John H. Lindsay,
            Department of Mathematics and Computer Science,
            Royal Military College of Canada,
            Kingston, Ontario, Canada, K7K 5L0.
 
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