On Tue, 7 Aug 2018, Alan Braslau wrote:

> Hello,
>
> You can also use MetaPost to render math stackers, rather than relying 
> on TeX constructs and any particular font.
>
> For example:
>
>
> \useMPlibrary[mat]
>
> \definemathstackers
>   [mp]
>   [alternative=mp]
>
> \definemathextensible [mp] [leftarrow]          ["2190]
> \definemathextensible [mp] [rightarrow]         ["2192]
> \definemathextensible [mp] [leftrightarrow]     ["2194]
> \definemathextensible [mp] [longleftrightarrow] ["27F7]
> \definemathextensible [mp] [rightoverleftarrow] ["21C4]
> \definemathextensible [mp] [underbrace]         ["FE3DF]
>
> \setupbodyfont [dejavu-condensed,12pt]
>
> \starttext
> $\rightarrow{≠a}$
> \stoptext
>
>
>
> Furthermore, the MP arrow can be tuned
>
> \startMPinitializations
>
> ahlength := .5EmWidth ;
> ahvariant := 1 ; % dimpled straight
>
> \stopMPinitializations
>
> as can line widths, etc.

Shouldn't we use a dedicated MP instance for stackers?

Aditya