# [NTG-context] Colon as non-operator

Hans Åberg haberg-1 at telia.com
Tue May 31 17:53:26 CEST 2016

> On 31 May 2016, at 17:04, Hans Hagen <pragma at 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