• CEX - Context-Free Expression Filter: update.

    From Rock Brentwood@21:1/5 to All on Sun Apr 4 16:55:10 2021
    The following is an update of the comp.compilers article

    "CEX - Context-Free Expression Filter"
    2007 February 25
    https://compilers.iecc.com/comparch/article/07-02-067

    Both an updated and UTF-8 converted version of the original have been
    posted under comp.theory here:

    https://groups.google.com/g/comp.theory/c/JTnm83_tWcA

    The following cites from the original have been updated:

    In 1993, the regular expression filter REX was introduced. Notable
    amongst its features was that processing was carried out entirely
    within an algebraic paradigm. The utility and the algorithms
    underlying it have eventually found their way into other applications
    (e.g. XML-Query).

    This was originally in the comp.compilers archive. The latest updates
    may now be found at GitHub under

    https://github.com/RockBrentwood/RegEx

    CEX is the long-planned successor to REX. It will not handle the full
    range of REX functionality, but will process language expressions at
    the next stage up the Chomsky hierarchy: Context-Free Expressions.
    The Untold Story of Formal Languages >http://federation.g3z.com/CompSci/index.htm#Untold
    (Numerous other references may be found on this page, both above and
    below this link)

    Currently linked at: https://web.archive.org/web/20080106150352/http://federation.g3z.com/CompSci/ index.htm#Untold

    Descriptions only are available, not the PDF's; and has been largely
    subsumed both by the following and publications recent and pending
    listed in the references (cited in the comp.theory article):

    The Algebraic Approach II-V https://www.scribd.com/document/235317956/The-Algebraic-Approach-II-V

    The new framework for context-free expressions, which is part of a new algebraic foundation for formal language and automata theory laid out
    in recent publications and elsewhere, is a descendant of the algebraic formulation published in 1963 by Chomsky and Schützenberger.

    A follow-up note to the 2018 papers that I sent both directly to
    Chomsky and as an open letter on the recent developments is here:

    https://www.scribd.com/document/392094748/The-evolution-of-recent-development s-in-formal-language-theory-from-the-1960-s

    An early draft of the presentation for one of the recent publications
    may be found here:

    Co Equalizers and Tensor Products for Idempotent Semirings https://www.scribd.com/document/392094657/Co-Equalizers-and-Tensor-Products-f or-Idempotent-Semirings

    More details may be found in the comp.theory article.

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