Re: [NTG-context] confusion about expansion

On 3/12/2014 10:21 AM, Wolfgang Schuster wrote:

Am 12.03.2014 um 15:12 schrieb Lars Huttar mailto:lars_huttar@sil.org>:

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On 3/12/2014 10:05 AM, Wolfgang Schuster wrote:

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Am 12.03.2014 um 15:00 schrieb Lars Huttar mailto:lars_huttar@sil.org>:

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Hello, I've got a running page head like this in my document:

\def\CurrentUser{\cldcontext{os.resultof"whoami"}}

\def\Markname { Compiled \date by \CurrentUser \LUATEX +\ConTeXt\ \contextversion }

and later:

\setlayer[cropmark][preset=lefttop,x=3cm,y=-1.5\lineheight]{\Markname}

But when I run this, I get a UCS error that seems to indicate that the *result* of \CurrentUser ("waxhaw\huttar") is getting parsed as a command sequence. When you want to pass a backslash to Lua you have to use \letterbackslash.

Thanks... can you give me an example of what that would look like? I don't think I want to pass a backslash to Lua, so I'm not sure how to apply what you're saying. Or are you using "Lua" here in the sense of LuaTeX?

A backslash appears in the output of os.resultof"whoami"; do I need to perform some processing on that output in order to escape backslashes?

Try this:

\def\CurrentUser{\cldcontext{os.resultof"whoami"}}

\def\Markname{Compiled \date by \detokenize\expandafter{\CurrentUser} \LUATEX +\ConTeXt\ \contextversion.}

\setuplayout[location=middle,marking=on]

\definelayer[cropmark][state=repeat,width=\paperwidth,height=\paperheight]

\setupbackgrounds[page][background=cropmark]

\setlayer[cropmark][preset=lefttop,x=3cm,y=1.5\lineheight]{\Markname}

\starttext

Foo

\stoptext

Thanks again... This gets rid of the error, but it seems to prevent any expansion of the content of \CurrentUser, because the page head now literally looks like this: Compiled March 12, 2014 by \cldcontext {os.resultof"whoami"}. LuaTEX+ConTEXt... Lars