Active character sequences

Active character sequences

[Giuseppe Bilotta]

Hello, these are a few things I would like to obtain with ConTeXt now:

1) I would like to have << and >> as synonyms for |<| and |>|;

2) I would like to be able to define in and easy way similar commands, to
give similar meanings to [[ and ]] (giving hollow opening and closing
brackets, which I have already assigned to appropriate cs's);

3) At the same time, I would like to use [ ... ] pairs as described in the
cont-new.tex module (\defineshortcuts, which only works with < ... > pairs);
is there a way to implement 2) without conflicting with 3)? Or to implement
1) without conflicting with \defineshortcuts?

Giuseppe Bilotta

Re: Active character sequences

[Johannes H?sing]

On Fri, Nov 24, 2000 at 10:18:34PM +0100, Giuseppe Bilotta wrote:
> Hello, these are a few things I would like to obtain with ConTeXt now:
> 
> 1) I would like to have << and >> as synonyms for |<| and |>|;
> 
> 2) I would like to be able to define in and easy way similar commands, to
> give similar meanings to [[ and ]] (giving hollow opening and closing
> brackets, which I have already assigned to appropriate cs's);
> 

Both of these would clash with the notation in Noweb, which is a very
common Literate Programming tool.

-- 
Johannes Hüsing <hannes@ruhrau.de> 

Re: Active character sequences

[Giuseppe Bilotta]

Johannes Hüsing wrote
> > Hello, these are a few things I would like to obtain with ConTeXt now:
> >
> > 1) I would like to have << and >> as synonyms for |<| and |>|;
> >
> > 2) I would like to be able to define in and easy way similar commands,
to
> > give similar meanings to [[ and ]] (giving hollow opening and closing
> > brackets, which I have already assigned to appropriate cs's);
> >
>
> Both of these would clash with the notation in Noweb, which is a very
> common Literate Programming tool.
>

Granted (even if I don't use Noweb, and only use, seldom, (C)WEB; what is
Noweb? References, anyone?). But what if I wanted to use them anyway?

Giuseppe Bilotta

Re: Active character sequences

[Giuseppe Bilotta]

> > Hello, these are a few things I would like to obtain with ConTeXt now:
> >
> > 1) I would like to have << and >> as synonyms for |<| and |>|;
> >
> By head (no docs currently here) it is
>    \setuplanguage
>        [leftquotation=$<<$,
>         rightquotation=$>>$]
>

Well, that's not exactly what I meant. I don't want $<<$ and $>>$ to be used
by |<| and |>|, I want to write << and >> instead of |<| and |>| (like in
LaTeX).

Giuseppe Bilotta

Re: Active character sequences

[Hans Hagen]

At 10:18 PM 11/24/00 +0100, Giuseppe Bilotta wrote:
>Hello, these are a few things I would like to obtain with ConTeXt now:
>
>1) I would like to have << and >> as synonyms for |<| and |>|;

This is a bad idea, since < [ ( are used for special purposes. Making <
active an active character is not a problem, but it may clash with other
functionality.  

>2) I would like to be able to define in and easy way similar commands, to
>give similar meanings to [[ and ]] (giving hollow opening and closing
>brackets, which I have already assigned to appropriate cs's);

That would brake all [parameters] since from then on "[ the active char"
would be different from "[ the other char' (in tex characters can have 16
different states!). Partial hacks are possible but never 100% safe. 

If your font would have a << as a ligature, it would be ok. 

>3) At the same time, I would like to use [ ... ] pairs as described in the
>cont-new.tex module (\defineshortcuts, which only works with < ... > pairs);

eh, core-new.tex i suppose, unless you have an old version

>is there a way to implement 2) without conflicting with 3)? Or to implement
>1) without conflicting with \defineshortcuts?

For the same reasons, as under (2) we can not use [] here, unless under a
specific regime, like: 

\startshortcuts
no setup commands, only [short] cuts
\stopshortcuts 

but i see more dangers than benefits. 

Anyhow, to prove the concept: 

\unprotect

\def\defineshortcut%
  {\dotripleargument\dodefineshortcut}

\def\dodefineshortcut[#1][#2][#3]%
  {\ifthirdargument
     \doifelsenothing{#1}
       {\dododefineshortcut[<>][#2][#3]}
       {\dododefineshortcut[#1][#2][#3]}%
   \else\ifsecondargument
     \dododefineshortcut[<>][#1][#2]%
   \else
     \dododefineshortcut[<>][][#1]%
   \fi\fi}

\def\dododefineshortcut[#1#2][#3][#4]% #1 is the trigger, #2 the delimiter
  {\doifundefined{\??te\??te\string#2}{\letvalue{\??te\??te\string#2}=#1}%
   \defineactivecharacter #1 {\@EA\doshortcut\string#2} %
   \getparameters
     [\??te\string#2#3]
     [\c!commandos=,\c!commando=,\c!letter=,\c!kleur=,#4]}

\def\doshortcut#1%
  {\ifmmode
     \getvalue{\??te\??te#1}%
   \else
     \bgroup
     \catcode`#1=\@@other
     \def\dodoshortcut##1#1%
       {\def\shorttag{\??te#1}%
        \def\shortcut{##1}%
        \dododoshortcut##1:\end}%
     \@EA\dodoshortcut
   \fi}

\def\dododoshortcut#1:#2\end
  {\doifelsenothing{#2}
     {\doifundefinedelse{\shorttag\c!commandos}
        {\shortcut}
        {\@EA\dodododoshortcut\@EA\shorttag\@EA:\shortcut:\end}}
     {\doifundefinedelse{\shorttag#1\c!commandos}
        {\shortcut}
        {\dodododoshortcut\shorttag#1:#2\end}}%
   \egroup}

\def\dodododoshortcut#1:#2:\end
  {\getvalue{#1\c!commandos}%
   \doattributes{#1}\c!letter\c!kleur{\getvalue{#1\c!commando}{#2}}}

\defineshortcut [<>] [i] [letter=\it]
\defineshortcut [()] [b] [letter=\bf]
\defineshortcut [++] [s] [letter=\sl]
\defineshortcut [//] [u] [letter=\underbars]
\defineshortcut [--] [a] [letter=\overstrike]

it seems <i:to work> well
it seems (b:to work) well
it seems +s:to work+ well
it seems /u:to work/ well
it seems -a:to work- well

But i must admit that i never used it so far, just playing a bit around -) 

Beware, this kind of trickery can spoil utility file loading in certain
cases [catcode clashing].  

Hans
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Re: Active character sequences

[Giuseppe Bilotta]

Ok, the game is not worth the candle. I will keep the suggestions in mind,
anyway, in case they might turn useful (especially the local-usableness in
specific contexts). Thank you all.

Giuseppe Bilotta