initial implementation

1 files changed, 146 insertions, 0 deletions

diff --git a/plugin/autobrace.vim b/plugin/autobrace.vim
new file mode 100644
index 0000000..acb92b8
--- /dev/null
+++ b/plugin/autobrace.vim
@@ -0,0 +1,146 @@
+if exists('g:loaded_autobrace') || &cp
+  finish
+endif
+let g:loaded_autobrace = 1
+
+let s:pair_chars = {
+\    '(': ')',
+\    '[': ']',
+\    '{': '}',
+\}
+let s:pair_cr_maps = {
+\    ')': "<SID>go_up()",
+\    ']': "<SID>go_up()",
+\    '}': "<SID>go_up()",
+\}
+let s:pair_bs_maps = {
+\    '"': "<SID>maybe_remove_adjacent_char('\"')",
+\    "'": "<SID>maybe_remove_adjacent_char(\"'\")",
+\    '(': "<SID>maybe_remove_empty_pair(')')",
+\    '[': "<SID>maybe_remove_empty_pair(']')",
+\    '{': "<SID>maybe_remove_empty_pair('}')",
+\    '': "<SID>maybe_collapse_pair()",
+\}
+
+function! s:move_cursor_left()
+    return "\<Esc>i"
+endfunction
+
+function! s:skip_closing_char(char)
+    if s:nextchar() == a:char
+        return "\<Esc>la"
+    else
+        return a:char
+    endif
+endfunction
+
+function! s:has_bs_mapping(char)
+    return has_key(s:pair_bs_maps, a:char)
+endfunction
+
+function! s:run_bs_mapping(char)
+    return eval(s:pair_bs_maps[a:char])
+endfunction
+
+function! s:has_cr_mapping(char)
+    return has_key(s:pair_cr_maps, a:char)
+endfunction
+
+function! s:run_cr_mapping(char)
+    return eval(s:pair_cr_maps[a:char])
+endfunction
+
+function! s:go_up()
+    return "\<CR>\<Esc>O"
+endfunction
+
+function! s:maybe_remove_adjacent_char(char)
+    if s:nextchar() == a:char
+        return "\<BS>\<Del>"
+    else
+        return "\<BS>"
+    endif
+endfunction
+
+function! s:maybe_remove_empty_pair(char)
+    let l:start = [line('.'), col('.')]
+    let l:end = searchpos('[^ \t]', 'cnWz')
+    if l:end == [0, 0]
+        return "\<BS>"
+    endif
+
+    let l:next_nonblank = s:charat(l:end[0], l:end[1])
+    if l:next_nonblank != a:char
+        return "\<BS>"
+    endif
+
+    let l:diff = [l:end[0] - l:start[0], l:end[1] - l:start[1]]
+    if l:diff[0] == 0
+        return "\<BS>" . repeat("\<Del>", l:diff[1] + 1)
+    elseif l:diff[0] == 1
+        return "\<Esc>" . (l:diff[0] + 1) . "Ji" . "\<BS>\<Del>"
+    else
+        return "\<Esc>" . (l:diff[0] + 1) . "Ji" . "\<BS>\<BS>\<Del>"
+    endif
+endfunction
+
+function! s:maybe_collapse_pair()
+    let l:prev_line_idx = line('.') - 1
+    if l:prev_line_idx < 1
+        return "\<BS>"
+    endif
+
+    let l:prev_line_char = s:charat(l:prev_line_idx, col([l:prev_line_idx, '$']) - 1)
+    if l:prev_line_char !~ '[([{]'
+        return "\<BS>"
+    endif
+
+    let l:end = searchpos('[^ \t]', 'cnWz')
+    if l:end == [0, 0]
+        return "\<BS>"
+    endif
+
+    let l:next_nonblank = s:charat(l:end[0], l:end[1])
+    if l:next_nonblank != s:pair_chars[l:prev_line_char]
+        return "\<BS>"
+    endif
+
+    return "\<Esc>\<BS>" . (l:end[0] - l:prev_line_idx + 1) . "Ji\<BS>"
+endfunction
+
+function! s:prevchar()
+    return s:charat(line('.'), col('.') - 1)
+endfunction
+
+function! s:nextchar()
+    return s:charat(line('.'), col('.'))
+endfunction
+
+function! s:charat(line, col)
+    return getline(a:line)[a:col - 1]
+endfunction
+
+for [s:start, s:end] in [['(', ')'], ['{', '}'], ['[', ']']]
+    exe "inoremap <silent> ".s:start.
+        \ " ".s:start.s:end."<C-R>=<SID>move_cursor_left()<CR>"
+    exe "inoremap <silent> ".s:end.
+        \ " <C-R>=<SID>skip_closing_char('".s:end."')<CR>"
+endfor
+inoremap <silent><expr> '
+    \ <SID>nextchar() == "'"
+        \ ? "\<C-R>=\<SID>skip_closing_char(\"'\")\<CR>"
+        \ : col('.') == 1 \|\| match(<SID>prevchar(), '\W') != -1
+            \ ? "''\<C-R>=\<SID>move_cursor_left()\<CR>"
+            \ : "'"
+inoremap <silent><expr> "
+    \ <SID>nextchar() == '"'
+        \ ? "\<C-R>=\<SID>skip_closing_char('\"')\<CR>"
+        \ : "\"\"\<C-R>=\<SID>move_cursor_left()\<CR>"
+inoremap <silent><expr> <BS>
+    \ <SID>has_bs_mapping(<SID>prevchar())
+        \ ? "\<C-R>=\<SID>run_bs_mapping(\<SID>prevchar())\<CR>"
+        \ : "\<BS>"
+inoremap <silent><expr> <CR>
+    \ <SID>has_cr_mapping(<SID>nextchar())
+        \ ? "\<C-R>=\<SID>run_cr_mapping(\<SID>nextchar())\<CR>"
+        \ : "\<CR>"