#7 fix - avoid enabling autoformat for code blocks

At least a partial fix for the problem of autoformat wreaking havoc on code blocks.

Couldn't find any highlighting groups for tables. If anybody can find them, we can add them to the exclude list.

autoload/pencil.vim

@@ -53,6 +53,27 @@ fun! s:imap(preserve_completion, key, icmd)
   en
 endf
 
+fun! s:enable_autoformat(mode)
+  " mode=1  InsertEnter
+  " mode=0  InsertLeave
+  if a:mode
+    " don't enable autoformat if in a code block (or table)
+    let l:okay_to_enable = 1
+    for l:sid in synstack(line('.'), col('.'))
+      if match(synIDattr(l:sid, 'name'),
+             \ g:pencil#autoformat_exclude_re) == -1
+        let l:okay_to_enable = 0
+        break
+      en
+    endfo
+    if l:okay_to_enable
+      set formatoptions+=a
+    en
+  el
+    set formatoptions-=a
+  en
+endf
+
 fun! pencil#setAutoFormat(mode)
   " 1=auto, 0=manual, -1=toggle
   if !exists('b:last_autoformat')
@@ -61,8 +82,8 @@ fun! pencil#setAutoFormat(mode)
   let b:last_autoformat = a:mode == -1 ? !b:last_autoformat : a:mode
   if b:last_autoformat
     aug pencil_autoformat
-      au InsertEnter <buffer> set formatoptions+=a
-      au InsertLeave <buffer> set formatoptions-=a
+      au InsertEnter <buffer> call s:enable_autoformat(1)
+      au InsertLeave <buffer> call s:enable_autoformat(0)
     aug END
   el
     sil! au! pencil_autoformat * <buffer>