fix(getvar): index_guides_ add to var in lookup

credits to @alerke

autoload/indent_guides.vim

@@ -19,7 +19,7 @@ endfunction
 " other buffers and windows.
 "
 function! indent_guides#process_autocmds() abort
-  if indent_guides#getvar('indent_guides_enable_on_vim_startup')
+  if indent_guides#getvar('enable_on_vim_startup')
     call indent_guides#enable()
   else
     call indent_guides#disable()
@@ -48,11 +48,11 @@ function! indent_guides#enable() abort
     let l:column_start = (l:level - 1) * s:indent_size + 1
 
     " define the higlight patterns and add to matches list
-    if indent_guides#getvar('indent_guides_space_guides')
-      let l:soft_pattern = indent_guides#indent_highlight_pattern(indent_guides#getvar('indent_guides_soft_pattern'), l:column_start, s:guide_size)
+    if indent_guides#getvar('space_guides')
+      let l:soft_pattern = indent_guides#indent_highlight_pattern(indent_guides#getvar('soft_pattern'), l:column_start, s:guide_size)
       call add(w:indent_guides_matches, matchadd(l:group, l:soft_pattern))
     end
-    if indent_guides#getvar('indent_guides_tab_guides')
+    if indent_guides#getvar('tab_guides')
       let l:hard_pattern = indent_guides#indent_highlight_pattern('\t', l:column_start, s:indent_size)
       call add(w:indent_guides_matches, matchadd(l:group, l:hard_pattern))
     end
@@ -200,19 +200,19 @@ function! indent_guides#init_script_vars() abort
   let s:hi_normal = substitute(s:hi_normal, ' font=[A-Za-z0-9:]\+', '', '')
 
   " shortcuts to the global variables - this makes the code easier to read
-  let s:debug             = indent_guides#getvar('indent_guides_debug')
-  let s:indent_levels     = indent_guides#getvar('indent_guides_indent_levels')
-  let s:auto_colors       = indent_guides#getvar('indent_guides_auto_colors')
-  let s:color_hex_pat     = indent_guides#getvar('indent_guides_color_hex_pattern')
-  let s:color_hex_bg_pat  = indent_guides#getvar('indent_guides_color_hex_guibg_pattern')
-  let s:color_name_bg_pat = indent_guides#getvar('indent_guides_color_name_guibg_pattern')
-  let s:start_level       = indent_guides#getvar('indent_guides_start_level')
+  let s:debug             = indent_guides#getvar('debug')
+  let s:indent_levels     = indent_guides#getvar('indent_levels')
+  let s:auto_colors       = indent_guides#getvar('auto_colors')
+  let s:color_hex_pat     = indent_guides#getvar('color_hex_pattern')
+  let s:color_hex_bg_pat  = indent_guides#getvar('color_hex_guibg_pattern')
+  let s:color_name_bg_pat = indent_guides#getvar('color_name_guibg_pattern')
+  let s:start_level       = indent_guides#getvar('start_level')
 
   " str2float not available in vim versions <= 7.1
   if has('float')
-    let s:change_percent = indent_guides#getvar('indent_guides_color_change_percent') / str2float('100.0')
+    let s:change_percent = indent_guides#getvar('color_change_percent') / str2float('100.0')
   else
-    let s:change_percent = indent_guides#getvar('indent_guides_color_change_percent') / 100.0
+    let s:change_percent = indent_guides#getvar('color_change_percent') / 100.0
   endif
 
   if s:debug
@@ -236,7 +236,7 @@ endfunction
 " NOTE: Currently, this only works when soft-tabs are being used.
 "
 function! indent_guides#calculate_guide_size() abort
-  let l:guide_size = indent_guides#getvar('indent_guides_guide_size')
+  let l:guide_size = indent_guides#getvar('guide_size')
 
   if l:guide_size == 0 || l:guide_size > s:indent_size
     let l:guide_size = s:indent_size
@@ -280,11 +280,11 @@ endfunction
 " Detect if any of the buffer filetypes should be excluded.
 "
 function! indent_guides#exclude_filetype() abort
-  if indent_guides#getvar('indent_guides_exclude_buftype') && &buftype !=# ''
+  if indent_guides#getvar('exclude_buftype') && &buftype !=# ''
     return 1
   endif
   for ft in split(&ft, '\.', 1)
-    if index(indent_guides#getvar('indent_guides_exclude_filetypes'), ft) > -1
+    if index(indent_guides#getvar('exclude_filetypes'), ft) > -1
       return 1
     end
   endfor
@@ -297,13 +297,6 @@ endfunction
 " return -1 if none of local buffer / global variable exists
 "
 function! indent_guides#getvar(var)
-  let varName=a:var
-  if (exists ("b:" . varName))
-    exe "let retVal=b:" . varName
-  elseif (exists ("g:" . varName))
-    exe "let retVal=g:" . varName
-  else
-    exe "let retVal=-1"
-  endif
-  return retVal
+  let l:varName = "indent_guides_" . a:var
+  return get(b:, l:varName, get(g:, l:varName, -1))
 endfunction