Add Fall.vim

2 files changed, 106 insertions, 0 deletions

diff --git a/autoload/fall.vim b/autoload/fall.vim
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index 0000000..493ded3
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+++ b/autoload/fall.vim
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+" Falling motions for Vim. "Falling" means moving the cursor down until it hits
+" text that doesn't match a pattern.
+
+" Returns an expression to be used in normal mode that results in the falling
+" motion. The semantics are as follows:
+"
+" The motion moves in the direction given by a:dir (which must be 'j' or 'k').
+" The motion moves while the character under the cursor does not match the
+" pattern, then it moves while the character under the cursor matches the
+" pattern stopping when the character under the cursor does not match the
+" pattern once again.
+"
+" ex.
+"
+" fall#fall('j', '^\s*$')
+"
+" for
+"
+" | t⌷is is some text
+" | this is some other text
+" |
+" |
+" | this is some bottom text
+" | this is some other bottom text
+"
+" will return an expression to update the cursor position to:
+"
+" | this is some text
+" | this is some other text
+" |
+" |
+" | t⌷is is some bottom text
+" | this is some other bottom text
+"
+" This works pretty well for navigating around languages that use indentation
+" and lack braces for bodies, i.e. vimscript, ruby. Less well for python, but
+" still okay.
+function! fall#fall(dir, pattern) abort
+  let i = 0
+  let n = 0
+
+  if a:dir == 'j'
+    let delta = 1
+  else
+    let delta = -1
+  endif
+
+  let line = line('.')
+  let column = col('.')
+  let c = v:count
+  if c == 0
+    let c = 1
+  endif
+
+  while i < c
+    let match = matchstr(getline(line), '\%' . column . 'c.')
+
+    while ! (match =~ a:pattern)
+      let n += 1
+      let line += delta
+      if line <= 0 || line >= line('$')
+        return "m'" . n . a:dir
+      endif
+      let match = matchstr(getline(line), '\%' . column . 'c.')
+    endwhile
+
+    while (match =~ a:pattern)
+      let n += 1
+      let line += delta
+      if line <= 0 || line >= line('$')
+        return "m'" . n . a:dir
+      endif
+      let match = matchstr(getline(line), '\%' . column . 'c.')
+    endwhile
+
+    let i += 1
+  endwhile
+
+  return "m'" . n . a:dir
+endfunction!
diff --git a/plugin/fall.vim b/plugin/fall.vim
new file mode 100644
index 0000000..3fba6d5
--- /dev/null
+++ b/plugin/fall.vim
@@ -0,0 +1,26 @@
+" Fall through whitespace.
+noremap <expr> <silent> <leader>k fall#fall('k', '^\s*$')
+noremap <expr> <silent> <leader>j fall#fall('j', '^\s*$')
+
+" Text object to fall through whitepacea
+onoremap <silent> <leader>k :<c-u>exec "normal! V" . fall#fall('k', '^\s*$')<cr>
+onoremap <silent> <leader>j :<c-u>exec "normal! V" . fall#fall('j', '^\s*$')<cr>
+
+" Text object to fall though whitespace, but exclude the last line.
+onoremap <silent> i<leader>k :<c-u>exec "normal! V" . fall#fall('k', '^\s*$') . "j"<cr>
+onoremap <silent> i<leader>j :<c-u>exec "normal! V" . fall#fall('j', '^\s*$') . "k"<cr>
+
+" Text object to fall though whitespace, but exclude the last line.
+onoremap <silent> i<leader>k :<c-u>exec "normal! V" . fall#fall('k', '^\s*$') . "j"<cr>
+onoremap <silent> i<leader>j :<c-u>exec "normal! V" . fall#fall('j', '^\s*$') . "k"<cr>
+
+" Text objects to describe "falling" down, and then "falling" up. Equivalent to
+" V<leader>kO<leader>j
+onoremap <silent> ai :<c-u>exec "normal! V" 
+      \ . fall#fall('j', '^\s*$') 
+      \ . "O"
+      \ . fall#fall('k', '^\s*$') <cr>
+onoremap <silent> ii :<c-u>exec "normal! V" 
+      \ . fall#fall('j', '^\s*$') 
+      \ . "kO"
+      \ . fall#fall('k', '^\s*$') . 'j' <cr>