From: Khaled Hosny <khaledhosny@eglug.org>
To: mailing list for ConTeXt users <ntg-context@ntg.nl>
Subject: Re: why nil argument
Date: Sun, 14 Nov 2010 21:53:09 +0200 [thread overview]
Message-ID: <20101114195309.GB21403@khaled-laptop> (raw)
In-Reply-To: <D772FB74-08AC-4345-929C-D80B068C36B4@uva.nl>
On Sun, Nov 14, 2010 at 08:47:30PM +0100, Hans van der Meer wrote:
>
> On 14 nov 2010, at 20:27, Khaled Hosny wrote:
>
> > On Sun, Nov 14, 2010 at 06:55:20PM +0100, Hans van der Meer wrote:
> >> In transforming dates through a Lua-call I get a nil error I do not understand.
> >>
> >> The luatex code =
> >> \startluacode
> >> hvdm = hvdm or {}
> >> require "lpeg"
> >> -- Transform date in Lua from yyyymmdd to dd-mm-yyyy with checks
> >> hvdm.day = lpeg.R("02") * lpeg.R("09") + lpeg.P("30") + lpeg.P("31") - lpeg.P("00")
> >> hvdm.month = lpeg.P("0") * lpeg.R("19") + lpeg.P("10") + lpeg.P("11") + lpeg.P("12")
> >> hvdm.year = lpeg.R("12") * lpeg.R("09") * lpeg.R("09") * lpeg.R("09")
> >> hvdm.date = lpeg.C(hvdm.year) * lpeg.C(hvdm.month) * lpeg.C(hvdm.day) * -1 / "%3-%2-%1"
> >> \stopluacode
> >> \def\FormatDate#1{\ctxlua{tex.print(tostring(hvdm.date:match(#1)))}}
> >>
> >> Calling \FormatDate(1) is OK although it returns "nil" (correct would be #1 = 20101114
> >> Calling \FormatDate(A) is not OK with the error:
> >
> > You are passing a undefined variable, A. Your argument should be quoted:
> >
> > hvdm.date:match("#1")
> >
>
> I would think that is not the case.
> For one, because then calling with argument 1 would fail in the same manner as argument A does; which does not happen.
No, match(1) will match an integer 1, match("1") matches a string "1",
while match(A) will match a variable A which is not what you are after,
while match("A") will match a string "A".
> Secondly, the call originates from
> \startxmlsetups xml:case:burned
> \xmldoifelsetext{#1}{}{\FormatDate{\xmlflush{#1}}}{\currentdate}
> \stopxmlsetups
> This does makes it a string already.
TeX is not lua, the concepts are completely and totally different.
> Something else must happen here, I guess.
No, there isn't.
Regards,
Khaled
--
Khaled Hosny
Arabic localiser and member of Arabeyes.org team
Free font developer
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prev parent reply other threads:[~2010-11-14 19:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-14 17:55 Hans van der Meer
2010-11-14 19:27 ` Khaled Hosny
2010-11-14 19:47 ` Hans van der Meer
2010-11-14 19:53 ` Khaled Hosny [this message]
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