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Message-ID:  <D4298EE7-4070-4D91-B364-A69CEF48428F@gmail.com>
Date:         Thu, 6 Aug 2009 17:31:15 +0930
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From: Will Robertson <wspr81@GMAIL.COM>
Subject: Re: xparse
To: LATEX-L@LISTSERV.UNI-HEIDELBERG.DE
In-Reply-To:  <4A7A857F.4010400@morningstar2.co.uk>
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Status: R

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On 06/08/2009, at 4:55 PM, Joseph Wright wrote:

> Suggestion (2):
>
> - o = standard optional LaTeX argument with no default value.
> - d = delimited optional argument where both the delimiters and  
> default
>      must be given.
> - b or n = optional braced argument (now have a choice!).

I'm more in favour of having the single letter with a possible  
optional default.
I still think that { o } and { o{default} } make the most sense.

> This means that "o" is a shortcut for "d[]{\NoValue}", and that any
> other case is handled "in full" using d.  This seems like a reasonable
> balance between making simple optional arguments easy and having a
> consistent syntax:
>
> \DeclareDocumentCommand \foo { o m } { }
> \DeclareDocumentCommand \foo { d[]{Stuff} m } { }
> \DeclareDocumentCommand \foo { d(){0,0} m } { } % Optional co- 
> ordinates

I like this way of doing coordinates. Could 'd{}{-default-}' be shoe- 
horned into this syntax as well? I suppose that would mean completely  
re-writing the parser. But then we wouldn't need another letter for my  
feature of limited value.

Will


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