Enabling extensions when using xmobar as a library?

[Solomon]

This may simply be an XY problem, but bear with me..

I want to use a a haskell source file to configure xmobar as shown here. I also would ideally like to be able to import arbitrary libraries to use in my config. However I am on nixos and this doesn't work out of the box:

➜ xmobar xmobar.hs
Error detected while loading xmobar configuration file: ./xmobar.hs

xmobar.hs:1:1: error:
    Could not find module ‘Xmobar’
    Use -v (or `:set -v` in ghci) to see a list of the files searched for.
  |
1 | import Xmobar
  | ^^^^^^^^^^^^^

Please check the file for errors.

So I made a cabal project called my-xmobar and imported the xmobar package as a dependency. I can now use your example xmobar.hs as my main.hs and run it. However, if I try to use XFT fonts then I get this error:

➜ cabal run 
Up to date
Warning: Xmobar must be built with the with_xft flag to support font 'xft:Bitstream Vera Sans Mono:size=11:bold:antialias=true.' Falling back on default.

Since I'm using xmobar as a library I don't see a way to enable that flag. Is there a way to enable all the extensions when using xmobar in this way? Alternatively, is there a simpler way to be able to run xmobar using a haskell source file and ideally be able to add arbitrary dependencies?

[Tony Zorman]

On Wed, Sep 01 2021 00:05, Solomon Bothwell wrote: Since I'm using `xmobar` as a library I don't see a way to enable that flag. Is there a way to enable all the extensions when using `xmobar` in this way?

At least `cabal install` takes a `--flag` argument in which you can specify which flags you would like to compile xmobar with. With stack, one can also specify a `flags` field in the stack.yaml file: flags: xmobar: with_xft: true I'm sure cabal has something similar.

[jao]

this is my xmobar-config repo, which uses xmobar as a library with cabal to create three different xmobar executables: https://codeberg.org/jao/xmobar-config i have together with it a checkout of xmobar, and xmobar-config uses that and compiles it with --all-extensions.

[Solomon]

Thank you this was really helpful!

[Guy Gastineau]

This is solved now right?
Should there be an example somewhere in this repository before closing the issue? Maybe not. I think it is a tooling use/discovery issue. Regardless, this issue helped me :)

[John Soo]

When used with cabal and using xmobar from xmonad, i have a cabal.project with a constraints stanza

constraints: xmobar +with_xft +with_alsa

[John Soo]

this is definitely a tooling discovery issue