For the Mercurial CLI version I have a few external diff tools defined. It would be great to use a specific tool in MacHG depending on the file I want to diff. At the moment I need to switch the global diff tool in the preferences.
A possible solution would be to include a sub menu "Diff selected files with >" (and maybe "Diff all files with >") in the context menu of the browser in the "Differences View". This sub menu would contain the diff tools availible in the preferences and the ones defined via hgrc. Another solution would be to the define the diff tool depending on the file type.
My motivation for having this feature is that I do not only version control source code but also other files which benefit from an applicable application for diffing them. As an example I version control docx files. For this I have written an AppleScript which allows me to diff the documents directly in Microsoft Word. I would like to trigger this diff from MacHG.