* What do \start and \stop mean?
@ 2013-09-30 15:38 Lars Huttar
2013-09-30 15:44 ` Aditya Mahajan
2013-09-30 16:00 ` luigi scarso
0 siblings, 2 replies; 5+ messages in thread
From: Lars Huttar @ 2013-09-30 15:38 UTC (permalink / raw)
To: mailing list for ConTeXt users
I found \start and \stop referenced in the context reference manual
(e.g. section 5.5).
While \startXYZ - \stopXYZ pairs are discussed earlier, I can't find any
place that \start and \stop (with no suffix) are described.
They seem to be used like \bgroup and \egroup. Is that right?
They are defined in core-sys.mkiv, but I can't figure out from there
what they actually do.
I'll contribute documentation for them if someone can tell me what they
mean.
Thanks,
Lars
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* Re: What do \start and \stop mean?
2013-09-30 15:38 What do \start and \stop mean? Lars Huttar
@ 2013-09-30 15:44 ` Aditya Mahajan
2013-09-30 17:53 ` Lars Huttar
2013-09-30 16:00 ` luigi scarso
1 sibling, 1 reply; 5+ messages in thread
From: Aditya Mahajan @ 2013-09-30 15:44 UTC (permalink / raw)
To: mailing list for ConTeXt users
On Mon, 30 Sep 2013, Lars Huttar wrote:
> I found \start and \stop referenced in the context reference manual
> (e.g. section 5.5).
> While \startXYZ - \stopXYZ pairs are discussed earlier, I can't find any
> place that \start and \stop (with no suffix) are described.
> They seem to be used like \bgroup and \egroup. Is that right?
> They are defined in core-sys.mkiv, but I can't figure out from there
> what they actually do.
(Untested, based on what I remember):
\start = \bgroup
\stop = \egroup
but \start scans the next argument, so there are situations when
\start may fail but \bgroup works.
\start[whatever] ... \stop = \startwhatever ... \stopwhatever
Aditya
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* Re: What do \start and \stop mean?
2013-09-30 15:44 ` Aditya Mahajan
@ 2013-09-30 17:53 ` Lars Huttar
0 siblings, 0 replies; 5+ messages in thread
From: Lars Huttar @ 2013-09-30 17:53 UTC (permalink / raw)
To: mailing list for ConTeXt users
On 9/30/2013 11:44 AM, Aditya Mahajan wrote:
> On Mon, 30 Sep 2013, Lars Huttar wrote:
>
>> I found \start and \stop referenced in the context reference manual
>> (e.g. section 5.5).
>> While \startXYZ - \stopXYZ pairs are discussed earlier, I can't find any
>> place that \start and \stop (with no suffix) are described.
>> They seem to be used like \bgroup and \egroup. Is that right?
>> They are defined in core-sys.mkiv, but I can't figure out from there
>> what they actually do.
>
> (Untested, based on what I remember):
>
> \start = \bgroup
> \stop = \egroup
>
> but \start scans the next argument, so there are situations when
> \start may fail but \bgroup works.
>
> \start[whatever] ... \stop = \startwhatever ... \stopwhatever
>
Ouch, that sounds like two very different behaviors, depending on
whether an argument is present.
I think I'll document \start at
http://wiki.contextgarden.net/Command/start
but take the usage of it out of the ref man's examples, replacing it
with { and }, as long as the examples still work. It's not important to
any of the examples.
Thanks, Aditya and Luigi, for the quick assist.
Lars
>
> Aditya
> ___________________________________________________________________________________
>
> 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
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> archive : http://foundry.supelec.fr/projects/contextrev/
> wiki : http://contextgarden.net
> ___________________________________________________________________________________
>
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: What do \start and \stop mean?
2013-09-30 15:38 What do \start and \stop mean? Lars Huttar
2013-09-30 15:44 ` Aditya Mahajan
@ 2013-09-30 16:00 ` luigi scarso
2013-09-30 16:32 ` luigi scarso
1 sibling, 1 reply; 5+ messages in thread
From: luigi scarso @ 2013-09-30 16:00 UTC (permalink / raw)
To: mailing list for ConTeXt users
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On Mon, Sep 30, 2013 at 5:38 PM, Lars Huttar <lars_huttar@sil.org> wrote:
> I found \start and \stop referenced in the context reference manual
> (e.g. section 5.5).
> While \startXYZ - \stopXYZ pairs are discussed earlier, I can't find any
> place that \start and \stop (with no suffix) are described.
> They seem to be used like \bgroup and \egroup. Is that right?
> They are defined in core-sys.mkiv, but I can't figure out from there
> what they actually do.
>
> I'll contribute documentation for them if someone can tell me what they
> mean.
>
> Thanks,
> Lars
>
core-sys.mkiv :
\unexpanded\def\start
{\dosingleempty\syst_start}
\def\syst_start
{\bgroup
\iffirstargument
\expandafter\syst_start_yes
\else
\expandafter\syst_start_nop
\fi}
\def\syst_start_yes[#1]%
{\edef\m_syst_start_stop{#1}%
\ifx\m_syst_start_stop\empty
\let\syst_stop_indeed\donothing
\else\ifcsname\e!start\m_syst_start_stop\endcsname
\expandafter\let\expandafter\syst_stop_indeed\csname\e!stop\m_syst_start_stop\endcsname
\csname\e!start\m_syst_start_stop\expandafter\expandafter\expandafter\endcsname
\else
\let\syst_stop_indeed\donothing
\fi\fi}
\def\syst_start_nop[#1]%
{\let\syst_stop_indeed\donothing}
\unexpanded\def\stop
{\syst_stop_indeed
\egroup}
(it should be \let\donothing\empty)
--
luigi
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___________________________________________________________________________________
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
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___________________________________________________________________________________
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: What do \start and \stop mean?
2013-09-30 16:00 ` luigi scarso
@ 2013-09-30 16:32 ` luigi scarso
0 siblings, 0 replies; 5+ messages in thread
From: luigi scarso @ 2013-09-30 16:32 UTC (permalink / raw)
To: mailing list for ConTeXt users
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On Mon, Sep 30, 2013 at 6:00 PM, luigi scarso <luigi.scarso@gmail.com>wrote:
>
>
>
> On Mon, Sep 30, 2013 at 5:38 PM, Lars Huttar <lars_huttar@sil.org> wrote:
>
>> I found \start and \stop referenced in the context reference manual
>> (e.g. section 5.5).
>> While \startXYZ - \stopXYZ pairs are discussed earlier, I can't find any
>> place that \start and \stop (with no suffix) are described.
>> They seem to be used like \bgroup and \egroup. Is that right?
>> They are defined in core-sys.mkiv, but I can't figure out from there
>> what they actually do.
>>
>> I'll contribute documentation for them if someone can tell me what they
>> mean.
>>
>> Thanks,
>> Lars
>>
>
>
>
>
> core-sys.mkiv :
>
>
> \unexpanded\def\start
> {\dosingleempty\syst_start}
>
> \def\syst_start
> {\bgroup
> \iffirstargument
> \expandafter\syst_start_yes
> \else
> \expandafter\syst_start_nop
> \fi}
>
> \def\syst_start_yes[#1]%
> {\edef\m_syst_start_stop{#1}%
> \ifx\m_syst_start_stop\empty
> \let\syst_stop_indeed\donothing
> \else\ifcsname\e!start\m_syst_start_stop\endcsname
>
> \expandafter\let\expandafter\syst_stop_indeed\csname\e!stop\m_syst_start_stop\endcsname
>
> \csname\e!start\m_syst_start_stop\expandafter\expandafter\expandafter\endcsname
> \else
> \let\syst_stop_indeed\donothing
> \fi\fi}
>
> \def\syst_start_nop[#1]%
> {\let\syst_stop_indeed\donothing}
>
> \unexpanded\def\stop
> {\syst_stop_indeed
> \egroup}
>
>
> (it should be \let\donothing\empty)
>
> sorry, hit return too early.
\start <...> \stop without argument is
\bgroup % from\def\syst_start
\expandafter\syst_start_nop
\syst_start_nop is
{\let\syst_stop_indeed\donothing}
and \stop is hence
\syst_stop_indeed
\egroup
i.e.
\donothing
\egroup
are like \bgroup <...> \egroup
It seems that there are no examples of \start[]<..>\stop .
--
luigi
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___________________________________________________________________________________
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://tex.aanhet.net
archive : http://foundry.supelec.fr/projects/contextrev/
wiki : http://contextgarden.net
___________________________________________________________________________________
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2013-09-30 15:38 What do \start and \stop mean? Lars Huttar
2013-09-30 15:44 ` Aditya Mahajan
2013-09-30 17:53 ` Lars Huttar
2013-09-30 16:00 ` luigi scarso
2013-09-30 16:32 ` luigi scarso
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