Re: [NTG-context] Trying to understand this ctxlua error
On 6 Apr 2020, at 02:54, Wolfgang Schuster
wrote:
>
> Gerben Wierda schrieb am 06.04.2020 um 00:41:
>> I got this error after I had changed some lua code:
>> tex error > tex error on line 272 in file archimate-lua.new: !
>> Undefined control sequence
>> warnIfVerbose( "Breaking off the processing of node %s\nNo
>> l...eak
>> xsi:type", node)
>> \luat_start_lua_code_indeed ...ormalexpanded {\endgroup \noexpand \directlua
>> {#1
>>
>> }}
>> l.272 \stopluacode
>>
>> The control sequence at the end of the top line of your error message was
>> never
>> \def'ed. You can just continue as I'll forget about whatever was undefined.
>> I have been looking at that code for over two hours, not seeing anything
>> wrong with it. But I’ve now finally found the culprit and I still do not get
>> it.
>> The culprit was:
>> warnIfVerbose( "Breaking off the processing of %s\n No
>> elementRef", node)
>> The problem goes away when I use:
>> warnIfVerbose( "Breaking off the processing of %s\nNo elementRef",
>> node)
>> (I don’t want the line after the node is printed to begin with a space).
>> But the lack of space between \n and N kills lua (apparently). For
>> completeness (as string.format and texio.write_nl are also in play):
>> function warnWithLabelIfVerbose( str, ... )
>> if verboseProgram then
>> texio.write_nl( str .. string.format(...))
>> end
>> end
>> function warnIfVerbose( ... )
>> warnWithLabelIfVerbose("-> ", ...)
>> end
>> Is this a lua bug? A ConTeXt bug? Expected behaviour? And if so, why is
>> reported that on line 272 (where \stopluacode is) is the error? Or is the
>> error message indeed helpful and do I just lack the know how to interpret it?
>
> ConTeXt expands TeX commands in a luacode-environment
> and when you have \n followed by text you create a new
> command with starts with \n but since it isn't defined
> you get a error message.
>
> In the example below the commented block produces
> the same error message as you get.
>
> \starttext
>
> %\startluacode
> %print("text\ntext")
> %\stopluacode
>
> \startluacode
> print("text\n text")
> \stopluacode
>
> \stoptext
OK, thanks. This means the ConTeXt environment mixes standard TeX (where \nfoo
would be considered a TeX command) and lua string substitution (where \nfoo
would mean a newline followed by foo), correct? I understand why that happens
(otherwise one would have to escape all \ characters directed at TeX) but it
really took me hours (because I did not understand the error message that
correctly told me \Nno was the problem). It’s what you see depends on what you
are looking for, I guess.
Maybe a warning in the documentation (or maybe there is one and I missed it)
G
___
If your question is of interest to others as well, please add an entry to the
Wiki!
maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage : http://www.pragma-ade.nl / http://context.aanhet.net
archive : https://bitbucket.org/phg/context-mirror/commits/
wiki : http://contextgarden.net
___
Re: [NTG-context] Trying to understand this ctxlua error
Gerben Wierda schrieb am 06.04.2020 um 00:41:
I got this error after I had changed some lua code:
tex error > tex error on line 272 in file archimate-lua.new: !
Undefined control sequence
warnIfVerbose( "Breaking off the processing of node %s\nNo
l...eak
xsi:type", node)
\luat_start_lua_code_indeed ...ormalexpanded {\endgroup \noexpand
\directlua {#1
}}
l.272 \stopluacode
The control sequence at the end of the top line of your error message
was never
\def'ed. You can just continue as I'll forget about whatever was undefined.
I have been looking at that code for over two hours, not seeing anything
wrong with it. But I’ve now finally found the culprit and I still do not
get it.
The culprit was:
warnIfVerbose( "Breaking off the processing of %s\n No
elementRef", node)
The problem goes away when I use:
warnIfVerbose( "Breaking off the processing of %s\nNo
elementRef", node)
(I don’t want the line after the node is printed to begin with a space).
But the lack of space between \n and N kills lua (apparently). For
completeness (as string.format and texio.write_nl are also in play):
function warnWithLabelIfVerbose( str, ... )
if verboseProgram then
texio.write_nl( str .. string.format(...))
end
end
function warnIfVerbose( ... )
warnWithLabelIfVerbose("-> ", ...)
end
Is this a lua bug? A ConTeXt bug? Expected behaviour? And if so, why is
reported that on line 272 (where \stopluacode is) is the error? Or is
the error message indeed helpful and do I just lack the know how to
interpret it?
ConTeXt expands TeX commands in a luacode-environment
and when you have \n followed by text you create a new
command with starts with \n but since it isn't defined
you get a error message.
In the example below the commented block produces
the same error message as you get.
\starttext
%\startluacode
%print("text\ntext")
%\stopluacode
\startluacode
print("text\n text")
\stopluacode
\stoptext
Wolfgang
___
If your question is of interest to others as well, please add an entry to the
Wiki!
maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage : http://www.pragma-ade.nl / http://context.aanhet.net
archive : https://bitbucket.org/phg/context-mirror/commits/
wiki : http://contextgarden.net
___
[NTG-context] Trying to understand this ctxlua error
I got this error after I had changed some lua code:
tex error > tex error on line 272 in file archimate-lua.new: ! Undefined
control sequence
warnIfVerbose( "Breaking off the processing of node %s\nNo
l...eak
xsi:type", node)
\luat_start_lua_code_indeed ...ormalexpanded {\endgroup \noexpand \directlua {#1
}}
l.272 \stopluacode
The control sequence at the end of the top line of your error message was never
\def'ed. You can just continue as I'll forget about whatever was undefined.
I have been looking at that code for over two hours, not seeing anything wrong
with it. But I’ve now finally found the culprit and I still do not get it.
The culprit was:
warnIfVerbose( "Breaking off the processing of %s\n No elementRef",
node)
The problem goes away when I use:
warnIfVerbose( "Breaking off the processing of %s\nNo elementRef",
node)
(I don’t want the line after the node is printed to begin with a space).
But the lack of space between \n and N kills lua (apparently). For completeness
(as string.format and texio.write_nl are also in play):
function warnWithLabelIfVerbose( str, ... )
if verboseProgram then
texio.write_nl( str .. string.format(...))
end
end
function warnIfVerbose( ... )
warnWithLabelIfVerbose("-> ", ...)
end
Is this a lua bug? A ConTeXt bug? Expected behaviour? And if so, why is
reported that on line 272 (where \stopluacode is) is the error? Or is the error
message indeed helpful and do I just lack the know how to interpret it?
G
(Took me three hours, this one. Just removing that space that happened with
some other changes was the culprit. Totally unexpected for me.)___
If your question is of interest to others as well, please add an entry to the
Wiki!
maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage : http://www.pragma-ade.nl / http://context.aanhet.net
archive : https://bitbucket.org/phg/context-mirror/commits/
wiki : http://contextgarden.net
___
