Colon as non-operator

Colon as non-operator

[Hans Åberg]

It is possible to get the symbol : COLON U+003A to expand to \colon, instead of the ratio operator, as it is now? The latter is rather rare in pure math, and in addition, it seems to have been reversed in the implementation with ∶ RATIO U+2236, cf. example below.

\setupbodyfont[xits,10pt]

\startformula
  \startalign
    \NC f\NC\colon A→B \NR % Produces ∶ RATIO U+2236
    \NC f\NC: A→B \NR  % : COLON U+003A
    \NC f\NC ∶ A→B \NR % ∶ RATIO U+2236
  \stopalign
\stopformula


___________________________________________________________________________________
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
___________________________________________________________________________________

Re: Colon as non-operator

[Hans Hagen]

On 5/31/2016 4:18 PM, Hans Åberg wrote:
> It is possible to get the symbol : COLON U+003A to expand to \colon, instead of the ratio operator, as it is now? The latter is rather rare in pure math, and in addition, it seems to have been reversed in the implementation with ∶ RATIO U+2236, cf. example below.
>
> \setupbodyfont[xits,10pt]
>
> \startformula
>   \startalign
>     \NC f\NC\colon A→B \NR % Produces ∶ RATIO U+2236
>     \NC f\NC: A→B \NR  % : COLON U+003A
>     \NC f\NC ∶ A→B \NR % ∶ RATIO U+2236
>   \stopalign
> \stopformula

it's a commented option i.e. we decided not to do that because the 
normal colon would be obscured then (just like overloading a period is 
not realistic)

Hans

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
       tel: 038 477 53 69 | www.pragma-ade.com | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
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
___________________________________________________________________________________

Re: Colon as non-operator

[Hans Åberg]

> On 31 May 2016, at 17:04, Hans Hagen <pragma@wxs.nl> wrote:
> 
> On 5/31/2016 4:18 PM, Hans Åberg wrote:
>> It is possible to get the symbol : COLON U+003A to expand to \colon, instead of the ratio operator, as it is now?

> it's a commented option

What does that mean?

> i.e. we decided not to do that because the normal colon would be obscured then (just like overloading a period is not realistic)

But can one not have it only in math, the way you suggested before, as in the code below?

Anyway, for Unicode fonts that support RATIO U+2236, input : COLON U+003A should properly give that RATIO in the output, and \colon should output a COLON. :-)


\setupbodyfont[xits,10pt]

\appendtoks
  \catcode`:=\activecatcode
  \letcharcode `: \colon
\to \everymathematics

\starttext

Note: the colon in text should behave normally.
\startformula
  \startalign
    \NC f\NC\colon A→B \NR % Outputs ∶ RATIO U+2236
    \NC f\NC: A→B \NR  % : COLON U+003A, outputs ∶ RATIO U+2236
    \NC f\NC ∶ A→B \NR % ∶ RATIO U+2236
  \stopalign
\stopformula

\stoptext


___________________________________________________________________________________
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
___________________________________________________________________________________

Re: Colon as non-operator

[Hans Hagen]

On 5/31/2016 5:53 PM, Hans Åberg wrote:
>
>> On 31 May 2016, at 17:04, Hans Hagen <pragma@wxs.nl> wrote:
>>
>> On 5/31/2016 4:18 PM, Hans Åberg wrote:
>>> It is possible to get the symbol : COLON U+003A to expand to \colon, instead of the ratio operator, as it is now?
>
>> it's a commented option
>
> What does that mean?

that it has been considered but rejected already

>> i.e. we decided not to do that because the normal colon would be obscured then (just like overloading a period is not realistic)
>
> But can one not have it only in math, the way you suggested before, as in the code below?

so what about (1:2) and so? do we really always want that colon symbol?

> Anyway, for Unicode fonts that support RATIO U+2236, input : COLON U+003A should properly give that RATIO in the output, and \colon should output a COLON. :-)
>
>
> \setupbodyfont[xits,10pt]
>
> \appendtoks
>   \catcode`:=\activecatcode
>   \letcharcode `: \colon
> \to \everymathematics

You love active characters yes? Try to avoid them. More efficient is:

\Umathcode"3A="6"00"002236 % : to \colon

in one of your styles

> \starttext
>
> Note: the colon in text should behave normally.
> \startformula
>   \startalign
>     \NC f\NC\colon A→B \NR % Outputs ∶ RATIO U+2236
>     \NC f\NC: A→B \NR  % : COLON U+003A, outputs ∶ RATIO U+2236
>     \NC f\NC ∶ A→B \NR % ∶ RATIO U+2236
>   \stopalign
> \stopformula
>
> \stoptext

could be a style (or option) but then more for a set of such symbols, 
not for just one

Hans


-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
       tel: 038 477 53 69 | www.pragma-ade.com | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
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
___________________________________________________________________________________