From: Hans Hagen <pragma@wxs.nl>
To: mailing list for ConTeXt users <ntg-context@ntg.nl>
Subject: Re: arguments to ctxlua
Date: Tue, 30 Mar 2010 19:52:54 +0200 [thread overview]
Message-ID: <4BB23A76.2030704@wxs.nl> (raw)
In-Reply-To: <A5FF035D-B4C4-444D-99C2-D438F34F808D@uva.nl>
On 30-3-2010 19:45, Hans van der Meer wrote:
> When I have a Lua function with 2 arguments:
> \startluacode
> function f(a,b)
> ...
> \stopluacode
>
> called through:
> \def\callf#1#2{\ctxlua{f("#1","#2")}}
>
> and do this actually with one argument:
> \callf{one}
so, #1 will be one and #2 will be the next token (whatever that is)
> then I find that the absent argument b in f(a,b) is not nil but a string
> of length 1.
>
> That is a bit of a nuisance because I would like to use the Lua idiom:
> function f(a,b)
> local b = b or default
> but that is frustrated by the behaviour shown.
>
> Is this an artifact of either luatex or ConTeXt? Can it be avoided such
> that in this case b will be nil?
just tex
but in any case even if #2 is empty you need to test like this
local b = b ~= "" and b or default
watch the order ... we want b to be set to b when not empty
Hans
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next prev parent reply other threads:[~2010-03-30 17:52 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-30 17:45 Hans van der Meer
2010-03-30 17:52 ` Hans Hagen [this message]
2010-03-30 18:30 ` Peter Münster
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