Re: Ctx & Lua: determination of the language being used

["Procházka Lukáš Ing. - Pontex s. r. o." <LPr@pontex.cz>]

... Thanks to both. So -

On Thu, 25 Nov 2010 13:31:36 +0100, Taco Hoekwater <taco@elvenkind.com> wrote:

> On 11/25/2010 01:13 PM, Wolfgang Schuster wrote:
>>
>> Am 25.11.2010 um 12:49 schrieb Procházka Lukáš Ing. - Pontex s. r. o.:
>>
>>> Hello,
>>>
>>> how to determine the current language being used in Ctx source via Lua? I mean soumething like:
>>>
>>> ---
>>> \mainlanguage[cz]
>>>
>>> \starttext
>>>   AAA
>>>
>>>   \startluacode
>>>     if     context.mainlanguage == "cz" then -- Do something specific
>>>       context("Ahoj!")
>>>     elseif context.mainlanguage == "en" then -- Do something specific
>>>       context("Hello!")
>>>     else
>>>     end
>>>   \stopluacode
>>> \stoptext
>>> ---
>>>
>>> So is there something like 'context.mainlanguage' or 'context.mainlanguage()' or 'tex.mainlanguage' or ...?
>>
>> \mainlanguage[...] ->  \currentmainlanguage
>> \language[...]     ->  \currentlanguage
>
> For the benefit of the mailing list archive, this means you
> can write in lua:
>
>     if "\currentmainlanguage"=="cz" then
>
> Except that that will not work because 'cz' is just an alias for 'cs',
> so you should test for that instead:
>
>
>      if "\currentmainlanguage"=="cs" then
>        context("Ahoj!")
>      elseif "\currentmainlanguage"=="en" then
>        context("Hello!")
>
> Best wishes,
> Taco

- In standalone Lua, the "\c" would be read (translated) as "c", as "\c" is not a valid escape sequence. See the test:

---
Microsoft Windows XP [Verze 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

C:\Lukas\ConTeXt\Samples\LuaTest>lua
Lua 5.1.4  Copyright (C) 1994-2008 Lua.org, PUC-Rio
> a="\currentmainlanguage"
> =a
currentmainlanguage
> =("\currentmainlanguage"=="currentmainlanguage")
true -- SO "\c" BECOMES "c"
---

So does it mean that "\<char>" (in the beginning of a string) in Lua for ConTeXt is a "hack" which expands a (Con)TeX(t) internal value (in the case that <char> is not a valid escape char)?

- If so, how to get an internal (Con)TeX(t) value which begins with a valid escape <char>, e.g. 't', so e.g. "\textwidth"? ("\t" should become <tab> in this case, or am I wrong?)

(Where to read about? I've been searching in luatexref-t.pdf...)

Lukas

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