printing tab in lua: print('a\tb') fails

printing tab in lua: print('a\tb') fails

[Mojca Miklavec]

Hello,

Here's a tiny question. The following command complains about
undefined control sequence.

\starttext
\startluacode
print('a\tb')
\stopluacode
hello
\stoptext

There is a workaround:
    print(string.format('a\t%s', 'b'))
but I find it weird. Even if the line above gets commented out with
two dashes it still complains.

I understand approximately why this happens, but is that intended?
Should I be using something else than \startluacode in the plethora of
different lua triggering commands?

Thanks,
   Mojca
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Re: printing tab in lua: print('a\tb') fails

[Wolfgang Schuster]

Am 26.11.2008 um 20:07 schrieb Mojca Miklavec:

> Hello,
>
> Here's a tiny question. The following command complains about
> undefined control sequence.
>
> \starttext
> \startluacode
> print('a\tb')

print('a\t b')

> \stopluacode
> hello
> \stoptext
>
> There is a workaround:
>    print(string.format('a\t%s', 'b'))
> but I find it weird. Even if the line above gets commented out with
> two dashes it still complains.
>
> I understand approximately why this happens, but is that intended?
> Should I be using something else than \startluacode in the plethora of
> different lua triggering commands?

\start/stopluacode is defined as \startluacode#1\stopluacode
(simplified) and you should take care of TeXs parsing rules.

If you want Lua comments and format command (\n, \t ...) use
a external file for your Lua code.

Wolfgang

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Re: printing tab in lua: print('a\tb') fails

[Mojca Miklavec]

On Wed, Nov 26, 2008 at 8:28 PM, Wolfgang Schuster wrote:
>
> Am 26.11.2008 um 20:07 schrieb Mojca Miklavec:
>
>> Hello,
>>
>> Here's a tiny question. The following command complains about
>> undefined control sequence.
>>
>> \starttext
>> \startluacode
>> print('a\tb')
>
> print('a\t b')

But then I get some unwanted space.

>> \stopluacode
>> hello
>> \stoptext
>>
>> There is a workaround:
>>    print(string.format('a\t%s', 'b'))
>> but I find it weird. Even if the line above gets commented out with
>> two dashes it still complains.
>>
>> I understand approximately why this happens, but is that intended?
>> Should I be using something else than \startluacode in the plethora of
>> different lua triggering commands?
>
> \start/stopluacode is defined as \startluacode#1\stopluacode
> (simplified) and you should take care of TeXs parsing rules.
>
> If you want Lua comments and format command (\n, \t ...) use
> a external file for your Lua code.

OK, I will use external files next time. In this quick-and-dirty
approach I just added string.format since it was easier than
restructuring everything.

I thought that \startluacode should be behaving the same way as
verbatim environments where commands inside verbatim have no
influence, but apparently I was wrong.

Thanks,
      Mojca
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Re: printing tab in lua: print('a\tb') fails

[luigi scarso]

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> OK, I will use external files next time. In this quick-and-dirty
> approach I just added string.format since it was easier than
> restructuring everything.
>
> I thought that \startluacode should be behaving the same way as
> verbatim environments where commands inside verbatim have no
> influence, but apparently I was wrong.
>
I also think so.
Can be strange, but inside a \startluacode\stopluacode I have no problems to
think at -- as comment
while I have problems to think to % as comment

And put lua code in a separate  file not always  is a good solution


-- 
luigi

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Re: printing tab in lua: print('a\tb') fails

[Wolfgang Schuster]

On Thu, Nov 27, 2008 at 9:42 AM, luigi scarso <luigi.scarso@gmail.com> wrote:
>
>
>>
>> OK, I will use external files next time. In this quick-and-dirty
>> approach I just added string.format since it was easier than
>> restructuring everything.
>>
>> I thought that \startluacode should be behaving the same way as
>> verbatim environments where commands inside verbatim have no
>> influence, but apparently I was wrong.
>
> I also think so.
> Can be strange, but inside a \startluacode\stopluacode I have no problems to
> think at -- as comment
> while I have problems to think to % as comment
>
> And put lua code in a separate  file not always  is a good solution

This would be really great, \start/stoplua with % for comments like \ctxlua
and \start/stopluacode with -- as comment, the first is used for longer settings
in macros and the second for inline functions.

@Luigi: You could try to parse the luacode content with Lpeg and with
the result back to \directlua.

Wolfgang
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Re: printing tab in lua: print('a\tb') fails

[luigi scarso]

[-- Attachment #1.1: Type: text/plain, Size: 1174 bytes --]

On Thu, Nov 27, 2008 at 10:02 AM, Wolfgang Schuster <
schuster.wolfgang@googlemail.com> wrote:

> On Thu, Nov 27, 2008 at 9:42 AM, luigi scarso <luigi.scarso@gmail.com>
> wrote:
> >
> >
> >>
> >> OK, I will use external files next time. In this quick-and-dirty
> >> approach I just added string.format since it was easier than
> >> restructuring everything.
> >>
> >> I thought that \startluacode should be behaving the same way as
> >> verbatim environments where commands inside verbatim have no
> >> influence, but apparently I was wrong.
> >
> > I also think so.
> > Can be strange, but inside a \startluacode\stopluacode I have no problems
> to
> > think at -- as comment
> > while I have problems to think to % as comment
> >
> > And put lua code in a separate  file not always  is a good solution
>
> This would be really great, \start/stoplua with % for comments like \ctxlua
> and \start/stopluacode with -- as comment, the first is used for longer
> settings
> in macros and the second for inline functions.
>
> @Luigi: You could try to parse the luacode content with Lpeg and with
> the result back to \directlua.
>

Better to study
luat-ini.tex
first

-- 
luigi

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Re: printing tab in lua: print('a\tb') fails

[Wolfgang Schuster]

On Thu, Nov 27, 2008 at 10:02 AM, Wolfgang Schuster
<schuster.wolfgang@googlemail.com> wrote:
> On Thu, Nov 27, 2008 at 9:42 AM, luigi scarso <luigi.scarso@gmail.com> wrote:
>>
>>
>>>
>>> OK, I will use external files next time. In this quick-and-dirty
>>> approach I just added string.format since it was easier than
>>> restructuring everything.
>>>
>>> I thought that \startluacode should be behaving the same way as
>>> verbatim environments where commands inside verbatim have no
>>> influence, but apparently I was wrong.
>>
>> I also think so.
>> Can be strange, but inside a \startluacode\stopluacode I have no problems to
>> think at -- as comment
>> while I have problems to think to % as comment
>>
>> And put lua code in a separate  file not always  is a good solution
>
> This would be really great, \start/stoplua with % for comments like \ctxlua
> and \start/stopluacode with -- as comment, the first is used for longer settings
> in macros and the second for inline functions.
>
> @Luigi: You could try to parse the luacode content with Lpeg and with
> the result back to \directlua.

Correction:

-- works as comments in luacode
% is used to format strings

Wolfgang
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Re: printing tab in lua: print('a\tb') fails

[luigi scarso]

[-- Attachment #1.1: Type: text/plain, Size: 690 bytes --]

>
>
> Correction:
>
> -- works as comments in luacode
> % is used to format strings
>


It's a bit different: code below is ok, and TeX comment is seen "before" lua
comment .
Only Hello! is print on pdf

%%%%%%%%%%%%%%%%%%
 \def\Foo{%
\startluacode
-- this is a lua comment
%%  this is a TeX comment
\stopluacode
}

\starttext
Hello !
\Foo
\stoptext
%%%%%%%%%%%%%%%%%%%




This is wrong

%%%%%%%%%%%%%%%%%%
\starttext
Hello !
\startluacode
-- this is a lua comment
%%  this is a TeX comment
\stopluacode
\stoptext
%%%%%%%%%%%%%%%%%%%



! LuaTeX error <main ctx instance>:3: unexpected symbol near '%'.
\@@expanded ... comment
%% this is a TeX comment
}

l.6 \stopluacode

?




-- 
luigi

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Re: printing tab in lua: print('a\tb') fails

[Hans Hagen]

luigi scarso wrote:
> 
>     Correction:
> 
>     -- works as comments in luacode
>     % is used to format strings
> 
> 
> 
> It's a bit different: code below is ok, and TeX comment is seen "before" 
> lua comment .
> Only Hello! is print on pdf
> 
> %%%%%%%%%%%%%%%%%%
>  \def\Foo{%
> \startluacode
> -- this is a lua comment
> %%  this is a TeX comment
> \stopluacode
> }

sure, since you use a \def which then stores catcodes as they are in tex 
mode

\startluacode
	function document.luigishouldknowbetter(whatever)
		for i=1,100 do
	 		print(whatever) -- this is a lua comment
		end
	end
\stopluacode

\def\Foo
   {\ctxlua{document.luigishouldknowbetter("Hello world!")}}


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                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
      tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
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Re: printing tab in lua: print('a\tb') fails

[luigi scarso]

[-- Attachment #1.1: Type: text/plain, Size: 1002 bytes --]

On Thu, Nov 27, 2008 at 1:03 PM, Hans Hagen <pragma@wxs.nl> wrote:

> luigi scarso wrote:
> >
> >     Correction:
> >
> >     -- works as comments in luacode
> >     % is used to format strings
> >
> >
> >
> > It's a bit different: code below is ok, and TeX comment is seen "before"
> > lua comment .
> > Only Hello! is print on pdf
> >
> > %%%%%%%%%%%%%%%%%%
> >  \def\Foo{%
> > \startluacode
> > -- this is a lua comment
> > %%  this is a TeX comment
> > \stopluacode
> > }
>
> sure, since you use a \def which then stores catcodes as they are in tex
> mode
>
> \startluacode
>        function document.luigishouldknowbetter(whatever)
>                for i=1,100 do
>                        print(whatever) -- this is a lua comment
>                end
>        end
> \stopluacode
>
> \def\Foo
>   {\ctxlua{document.luigishouldknowbetter("Hello world!")}}
>
>
Exactly.
In my opinion, this is better than my example, because I don't like to mix
things  (and also for namespace document).


-- 
luigi

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Re: printing tab in lua: print('a\tb') fails

[Wolfgang Schuster]

On Thu, Nov 27, 2008 at 9:29 AM, Mojca Miklavec
<mojca.miklavec.lists@gmail.com> wrote:
> On Wed, Nov 26, 2008 at 8:28 PM, Wolfgang Schuster wrote:
>>
>> Am 26.11.2008 um 20:07 schrieb Mojca Miklavec:
>>
>>> Hello,
>>>
>>> Here's a tiny question. The following command complains about
>>> undefined control sequence.
>>>
>>> \starttext
>>> \startluacode
>>> print('a\tb')
>>
>> print('a\t b')
>
> But then I get some unwanted space.

print('a\string\tb')

>>> \stopluacode
>>> hello
>>> \stoptext

Wolfgang
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Re: printing tab in lua: print('a\tb') fails

[Hans Hagen]

Mojca Miklavec wrote:

> I thought that \startluacode should be behaving the same way as
> verbatim environments where commands inside verbatim have no
> influence, but apparently I was wrong.

no, more like MPcode where one can mix things

if the luacode would not expand macros, then we'd need rather tricky 
code when we'd like to have tex put stuff in there


\startluacode
     print('a\string\tb')
\stopluacode

Hans

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
      tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
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___________________________________________________________________________________

Re: printing tab in lua: print('a\tb') fails

[Hans Hagen]

Mojca Miklavec wrote:
> Hello,
> 
> Here's a tiny question. The following command complains about
> undefined control sequence.
> 
> \starttext
> \startluacode
> print('a\tb')

	print('a\\tb')

> \stopluacode
> hello
> \stoptext

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
      tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
-----------------------------------------------------------------
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