I can add a word to the local dictionary or spellfile with zg.
I can use zG to add a word to the internal spellfile, but this still affects all loaded files.
How can I add spelling exceptions on a per-file or per-buffer basis, and have it still work when re-opening the file?
Is there some .viminfo magic for this?
There's nothing built-in; I guess the reasoning is that spelling (at least for a certain language) is inherently global. Any differences should be reflected in the language / dialect chosen.
You can implement such buffer-local spelling exception yourself: Get a temp file via tempname(), prepend it to 'spellfile', and then zg / 1zg will place the exception there. This would be local to a single Vim session (like zG).
If you would like persistent buffer-local spelling, instead of tempname(), either put the spell file next to the file (bufname('') . '.spl'), or place then all into a dedicated spell directory, encoding the original file path in a way that :mkview does: replace the path separator with =+ and = with ==. So, ~/foo/bar.txt would get a spellfile of /path/to/spelldir/~=+foo=+bar.txt.spl
tempname() with something more static. See my edit.
– Ingo Karkat
Oct 18 '16 at 8:48
