[Agda] font issue in emacs mode

[Paolo Capriotti]

On Thu, Sep 25, 2014 at 2:09 PM, Martin Escardo <m.escardo at cs.bham.ac.uk> wrote:
> I am using ubuntu 14.04.1 with Agda 2.4.2 via cabal. Works fine.
>
> However, some fonts don't display correctly. For example, \b1 (blackboard
> one) displays as some hexadecimal numbers in a box.
>
> Such symbols display ok with the same version of Agda but in ubuntu 12.04.
>
> Does anybody know how to solve this for ubuntu 14.04? I suspect there is a
> missing ubuntu package that I should install.

Which font are you using in emacs? Here is a list of fonts supporting
this particular character:
http://www.fileformat.info/info/unicode/char/1d7d9/fontsupport.htm

You can find out the code point corresponding to a missing glyph with
`C-u C-x =` within emacs.

That particular glyph was missing in my setup as well, so I tried

    (set-fontset-font "fontset-default" 'unicode "DejaVu Sans")

as suggested [here](http://stackoverflow.com/questions/6083496/how-do-you-specify-a-fallback-font-in-emacs)
and that seems to have fixed it. Make sure you have the `fonts-dejavu`
package installed if you do that.

Paolo