Re: Extending REG-EXP to 2-Dimension.

lloyd@kauri.vuw.ac.nz (Lloyd Parkes)
Mon, 5 Dec 1994 04:03:09 GMT

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Extending REG-EXP to 2-Dimension. mosh@ramanujan.cs.albany.edu (1994-11-21)
Re: Extending REG-EXP to 2-Dimension. steve@cegelecproj.co.uk (1994-11-30)
Re: Extending REG-EXP to 2-Dimension. ruiter@ruls41.fsw.leidenuniv.nl (1994-12-01)
Re: Extending REG-EXP to 2-Dimension. rockwell@nova.umd.edu (1994-12-03)
Re: Extending REG-EXP to 2-Dimension. lloyd@kauri.vuw.ac.nz (1994-12-05)
Re: Extending REG-EXP to 2-Dimension. pwk@eb.ele.tue.nl (1994-12-05)
Re: Extending REG-EXP to 2-Dimension. steve@cegelecproj.co.uk (1994-12-05)
Re: Extending REG-EXP to 2-Dimension. bakul@netcom.com (1994-12-08)
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Newsgroups: comp.compilers
From: lloyd@kauri.vuw.ac.nz (Lloyd Parkes)
Keywords: lex, DFA
Organization: Victoria Uni. of Wellington, NZ.
References: 94-11-137 94-12-021
Date: Mon, 5 Dec 1994 04:03:09 GMT

ruiter@ruls41.fsw.leidenuniv.nl (Jan-Peter de Ruiter) writes:
      [[ Request for regexp systems that work on "boxes" of text ]]


      [Discussion of circular structures]


Why not just add operations that work in the vertical dimension? We
already have concatenation, repetition and alternation horizontally,
why not just define similar vertical operations? e.g.


. horizontal concatenation
* horizontal repetition
| horizontal alternation
, vertical concatenation
# vertical repetition
! vertical alternation


with parenthesis having their usual meanings.


This would mean that a.b,c# would match


ab
c
c
c


and perhaps a,(c.b)# might match


a
cb
cb
cb


This might not be as powerful as one might like, but it would be easy
to implement and it could be argued that anything more powerful falls
into the category of 2D pattern matching rather than 2D regular
expressions.


Cheers,
Lloyd
--
Lloyd Parkes, one of the plethora of Systems Managers here at Victoria
University's Information Technology Services.
--


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