Add uncommented code for spellfile extension

2 files changed, 22 insertions, 4 deletions

diff --git a/IDEAS.md b/IDEAS.md
index 6e098377..7c42cc96 100644
--- a/IDEAS.md
+++ b/IDEAS.md
@@ -33,7 +33,3 @@ Ideas
   some point
 * I'd like a Git hook that pre-fills out "Version X.Y.Z" if making an annotated
   tag named `vX.Y.Z`.
-* I'd like to make the zG command in Vim a bit more useful by maintaining
-  a per-file cache of added words, indexed by path, mapping it to 2zg or 3zg
-  rather like Steve Losh does.  I wouldn't think it would be too hard;
-  'spellfile' is a buffer-local option.
diff --git a/vim/vimrc b/vim/vimrc
index 95ca61ae..737b9fd6 100644
--- a/vim/vimrc
+++ b/vim/vimrc
@@ -902,6 +902,28 @@ if $MYVIM !=# '' && $MYVIM !~# '[*?[|;&<>\r\n]'
   set thesaurus^=$MYVIM/ref/thesaurus.txt
 endif
 
+EnsureDir $MYVIM/cache/spell
+
+let spellfile = join([
+      \ substitute(v:lang, '_.*', '', ''),
+      \ &encoding
+      \ ], '.') . '.add'
+execute 'set spellfile=$MYVIM/cache/spell/'.spellfile
+
+EnsureDir $MYVIM/cache/spell/local
+
+function! AddLocalSpellfile() abort
+  let spellfile = join([
+        \ substitute(expand('%:p'), '[^0-9A-Za-z_.-]', '%', 'g'),
+        \ substitute(v:lang, '_.*', '', ''),
+        \ &encoding
+        \ ], '.') . '.add'
+  setlocal spellfile<
+  execute 'setlocal spellfile+=$MYVIM/cache/spell/local/'.spellfile
+ndfunction!
+autocmd vimrc BufRead *
+      \ call AddLocalSpellfile() | nnoremap <buffer> zG 2zg
+
 " Use all of the filetype detection, plugin, and indent support available.
 " I define my own filetype.vim and scripts.vim files for filetype detection,
 " in a similar but not identical form to the stock runtime files.  I also