[NTG-context] \coloneqq

[Aditya Mahajan]

On Fri, 14 Sep 2007, Jesse Alama wrote:

> I'd like to use a colon-equals sign symbol to indicate a definition.
> According to The Comprehensive LaTeX Symbol List, this symbol is
> available in the txfonts (LaTeX) package.  However, it seems that the
> txfonts support in ConTeXt doesn't contain that symbol.  And, in any
> case, a search for \coloneqq on the wiki gave no results.  Perhaps the
> symbol I want isn't called coloneqq in ConTeXt, or perhaps the symbol is
> currently missing.  How can I get this symbol in my ConTeXt document?

The symbol is called \colonequals. Other colon symbols are (from 
math-ext.tex)

%D \macros
%D   {centercolon, colonminus, minuscolon, colonequals, equalscolon,
%D    colonapprox, approxcolon, colonsim, simcolon, coloncolon,
%D    coloncolonminus, minuscoloncolon, coloncolonequals,
%D    equalscoloncolon, coloncolonapprox, approxcoloncolon,
%D    colonsim, simcoloncolon}
%D
%D In $a := b$ the colon is not vertically centered with the equal
%D to. Also the distance between colon and equal to is a bit large.
%D So, we define a vertically centered colon \tex {centercolon} and
%D a few macros for colon and double colon relation symbols.
%D
%D \startlines
%D \formula {A \centercolon       B}
%D \formula {A \colonminus        B}
%D \formula {A \minuscolon        B}
%D \formula {A \colonequals       B}
%D \formula {A \equalscolon       B}
%D \formula {A \colonapprox       B}
%D \formula {A \approxcolon       B}
%D \formula {A \colonsim          B}
%D \formula {A \simcolon          B}
%D \formula {A \coloncolon        B}
%D \formula {A \coloncolonminus   B}
%D \formula {A \minuscoloncolon   B}
%D \formula {A \coloncolonequals  B}
%D \formula {A \equalscoloncolon  B}
%D \formula {A \coloncolonapprox  B}
%D \formula {A \approxcoloncolon  B}
%D \formula {A \colonsim          B}
%D \formula {A \simcoloncolon     B}
%D \stoplines

The naming is after colonequals.sty rather than mathtools.sty. I find 
these names easier to remember, but if you want mathtools type names, 
it is easy to create aliases by \let\coloneqq=\colonequals and so on.

Perhaps it is time to create a comprehensive math symbol list for 
ConTeXt also....

Aditya