\startmode and \ignorespaces

\startmode and \ignorespaces

[Hans van der Meer]

A little while ago I asked whether \doifmode and friends should have an \ignorespaces at the end. Hans Hagen answered "no" and after some reasoning (probably along the same lines as his) I agree with him. Thus one uses in a quite natural way:
   some text\doifmode{xyz}{ conditional text} following text
doing nothing else than: some text conditional text following text.
With regard to this it is understandable and correct that extra space is taken in the next construct:
   some text \doifmode{xyz}{ conditional text} following text.

But it looks different to me when using the \startmode .. \stopmode pair.
---- some text.
\startmode[xyz]
some conditional text.
\stopmode
further text.

In order to avoid here the extra space one has to code an extra %
---- some text.
\startmode[xyz]%
some conditional text.
\stopmode
further text.

or (not preferred imho):
---- some text.%
\startmode[xyz]

I think this is error prone as it is al too easy to forget the %. The situation here differs from the \doifmode-case. I tend to believe that the fact that the \startmode[] .. \stopmode construct invites one to separate the statements with newlines (whitespace thus). Therefore I would ask if this plea for an \ignorespaces effect at the end of the \startmode[xyz] should be honored.

Hans van der Meer

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Re: \startmode and \ignorespaces

[Meer, H. van der]

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I made an example of the effect of this on \doifmode and \startmode. The example shows that the appearance of extra space in \doifmode follows a regular pattern. The startmode case differs in that respect because \startmode[condition-true] has the extra space but \startmode[condition-false] has not. In my view that is an unwanted anomaly. A little redefinition remedies that as can be seen in the example.


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On 13 okt. 2011, at 17:43, Hans van der Meer wrote:

> A little while ago I asked whether \doifmode and friends should have an \ignorespaces at the end. Hans Hagen answered "no" and after some reasoning (probably along the same lines as his) I agree with him. Thus one uses in a quite natural way:
>   some text\doifmode{xyz}{ conditional text} following text
> doing nothing else than: some text conditional text following text.
> With regard to this it is understandable and correct that extra space is taken in the next construct:
>   some text \doifmode{xyz}{ conditional text} following text.
> 
> But it looks different to me when using the \startmode .. \stopmode pair.
> ---- some text.
> \startmode[xyz]
> some conditional text.
> \stopmode
> further text.
> 
> In order to avoid here the extra space one has to code an extra %
> ---- some text.
> \startmode[xyz]%
> some conditional text.
> \stopmode
> further text.
> 
> or (not preferred imho):
> ---- some text.%
> \startmode[xyz]
> 
> I think this is error prone as it is al too easy to forget the %. The situation here differs from the \doifmode-case. I tend to believe that the fact that the \startmode[] .. \stopmode construct invites one to separate the statements with newlines (whitespace thus). Therefore I would ask if this plea for an \ignorespaces effect at the end of the \startmode[xyz] should be honored.
> 
> Hans van der Meer
> 
> ___________________________________________________________________________________
> 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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___________________________________________________________________________________

Re: \startmode and \ignorespaces

[Wolfgang Schuster]

Am 14.10.2011 um 10:38 schrieb Meer, H. van der:

> I made an example of the effect of this on \doifmode and \startmode. The example shows that the appearance of extra space in \doifmode follows a regular pattern. The startmode case differs in that respect because \startmode[condition-true] has the extra space but \startmode[condition-false] has not. In my view that is an unwanted anomaly. A little redefinition remedies that as can be seen in the example.

I wrote you already a few times that you can use the annotation module for this. The module serves also as replacement for the fixme module where it is necessary to take care that no extra spaces are added when the text is hidden.

\usemodule[annotation]

\defineannotation[fulltext] [alternative=text]
\defineannotation[shorttext][alternative=none]
\defineannotation[modetext] [alternative=command,command=\ModeText]

\define[2]\ModeText
  {\doifelse{\placeannotationtitle}{off}{\removeunwantedspaces}{#2}}

\starttext

abc \fulltext {pqr} xyz

abc \shorttext{pqr} xyz

abc \fulltext [alternative=none]{pqr} xyz

abc \shorttext[alternative=text]{pqr} xyz

\blank

abc \startfulltext  pqr \stopfulltext  xyz

abc \startshorttext pqr \stopshorttext xyz

abc \startfulltext [alternative=none] pqr \stopfulltext  xyz

abc \startshorttext[alternative=text] pqr \stopshorttext xyz

\blank

abc \modetext     {pqr} xyz

abc \modetext {on}{pqr} xyz

abc \modetext{off}{pqr} xyz

\blank

abc \startmodetext      pqr \stopmodetext xyz

abc \startmodetext{on}  pqr \stopmodetext xyz

abc \startmodetext{off} pqr \stopmodetext xyz

\stoptext

Wolfgang
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Re: \startmode and \ignorespaces

[Meer, H. van der]

On 14 okt. 2011, at 11:26, Wolfgang Schuster wrote:

> 
> Am 14.10.2011 um 10:38 schrieb Meer, H. van der:
> 
>> I made an example of the effect of this on \doifmode and \startmode. The example shows that the appearance of extra space in \doifmode follows a regular pattern. The startmode case differs in that respect because \startmode[condition-true] has the extra space but \startmode[condition-false] has not. In my view that is an unwanted anomaly. A little redefinition remedies that as can be seen in the example.
> 
> I wrote you already a few times that you can use the annotation module for this. The module serves also as replacement for the fixme module where it is necessary to take care that no extra spaces are added when the text is hidden.


Wolfgang,

Thanks for your reply, but I find it takes a sidetrack and does not answer the question. Please let me explain.

It might well be that the annotation module does something of the sort, but that is not my point. The mode-mechanism is explicitely given as a means to do conditional typesetting. If I may cite from the wiki: "Very often, you want to generate multiple versions of the same document: one version for printing and one for viewing on the screen, one version for students and one version for the instructor, and so on. .. Or you could use modes - the ConTeXt way of doing conditional processing" 

Well, that is exactly what I want to do and I fail to see why another module (like annotation) should be necessary. Therefore, please do not keep pointing me to something that in my opinion is not needed in this case and is already fully provided for in ConTeXt.

When I am pointing out something that I think is an anomaly in the behaviour of ConTeXt or probably not intentional, it is not meant as criticizing. To the contrary, my intention is always to make a constructive contribution. Your reply however is not an answer to the question I brought forward. It might be that there are reasons for not changing ConTeXt in the manner I proposed on this issue. I can live with that, because I have no role in the development. But I think it is legitimate to ask why that decision is made. I am certain you will understand this.

Hans van der Meer


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Re: \startmode and \ignorespaces

[Hans Hagen]

On 14-10-2011 10:38, Meer, H. van der wrote:
> I made an example of the effect of this on \doifmode and \startmode. The example shows that the appearance of extra space in \doifmode follows a regular pattern. The startmode case differs in that respect because \startmode[condition-true] has the extra space but \startmode[condition-false] has not. In my view that is an unwanted anomaly. A little redefinition remedies that as can be seen in the example.

it's all a side effect of how parses: spaces after a \cs are gobbled so 
any macro that looks ahead has to struggle with this and compromise

you can consider using

\startsetups xxx

\stopsetups

\doifmode{whatever}{\setups{xxx}

inside setups all spaces and line endings are ignores (so an explicit 
one has to be \space)

Hans


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