fixing smart tab completion

vim/vimrc.symlink

@@ -290,26 +290,26 @@ autocmd! BufEnter * call ApplyLocalSettings(expand("<afile>:p:h"))
 
 " smart tab completion
 function! Smart_TabComplete()
-    let line = getline('.')
-    let substr = strpart(line, -1, col('.')+1)
+    let line = getline('.')                         " current line
 
-    let substr = matchstr(substr, "[^ \t]*$")
-    if (strlen(substr) == 0)
-        return "<\tab>"
+    let substr = strpart(line, -1, col('.')+1)      " from the start of the current
+    " line to one character right
+    " of the cursor
+    let substr = matchstr(substr, "[^ \t]*$")       " word till cursor
+    if (strlen(substr)==0)                          " nothing to match on empty string
+        return "\<tab>"
     endif
-    let has_period = match(substr, '\.') != -1
-    let has_slash = match(substr, '\/') != -1
+    let has_period = match(substr, '\.') != -1      " position of period, if any
+    let has_slash = match(substr, '\/') != -1       " position of slash, if any
     if (!has_period && !has_slash)
-        return "\<C-X>\<C-P>"
-    elseif (has_slash)
-        return "\<C-X>\<C-F>"
+        return "\<C-X>\<C-P>"                         " existing text matching
+    elseif ( has_slash )
+        return "\<C-X>\<C-F>"                         " file matching
     else
-        return "\<C-X>\<C-O>"
+        return "\<C-X>\<C-O>"                         " plugin matching
     endif
 endfunction
-
 inoremap <tab> <c-r>=Smart_TabComplete()<CR>
-
 """""""""""""""""""""""""""""""""""""""""""""""""""""""""""
 " => Plugins
 """""""""""""""""""""""""""""""""""""""""""""""""""""""""""
@@ -331,9 +331,9 @@ nmap <silent> <leader>r :CtrlPBuffer<cr>
 
 " CtrlP ignore patterns
 let g:ctrlp_custom_ignore = {
-    \ 'dir': '\.git$\|node_modules$\|\.hg$\|\.svn$',
-    \ 'file': '\.exe$\|\.so$'
-\ }
+            \ 'dir': '\.git$\|node_modules$\|\.hg$\|\.svn$',
+            \ 'file': '\.exe$\|\.so$'
+            \ }
 
 " search the nearest ancestor that contains .git, .hg, .svn
 let g:ctrlp_working_path_mode = 2