problem with string matching

[Pablo Rodriguez <oinos@gmx.es>]

Dear list,

I have this sample:

    \starttext
    \startluacode
    a = "asdfasd123"
    b = a:match("%d+")
    context(b)
    c = "123"
    context(c)
    if b==c then context("yes") else context("no") end

    function document.numbers_only(str)
      context(str:gsub("[%a%p]", ""))
    end

    function document.only_numbers(str)
      context(str:match("%d+"))
    end

    function document.compare_strings(one, two)
      if one == two then context("Yes") else context ("No") end
    end
    \stopluacode

    \unexpanded\def\numbersonly#1%
        {\ctxlua{document.numbers_only("#1")}}

    \unexpanded\def\onlynumbers#1%
        {\ctxlua{document.only_numbers("#1")}}

    \unexpanded\def\comparestrings#1#2%
        {\ctxlua{document.compare_strings("#1", "#2")}}

    \def\rstring{abc123}

    \numbersonly{abc123}

    \onlynumbers{abc123}

    \doifelse{\numbersonly{\rstring}}{abc123}{yes}{no}

    \doifelse{abc123}{\onlynumbers{\rstring}}{yes}{no}

    \comparestrings{\numbersonly{\rstring}}{123}

    \comparestrings{123}{123}, \comparestrings{1}{123}
    \stoptext

I need to extract the digits from a string, which actually comes from
the "--arguments" option in the command line.

I need to compare the string with real numbers. But for some reason
unknown to me, this is more complex than I thought.

Could anyone explain me what I am doing wrong?

Many thanks for your help,

Pablo
--
http://www.ousia.tk
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