Vim Powerline with Syntastic segment

Question

How do I add a syntastic segment to the powerline footer for Vim? (the new powerline, not vim-powerline) Syntastic docs only say how to add it to the standard Vim footer and I couldn't find how to add it in the powerline docs.

Answer 1

Most of these instruction come from this pull request (451) for powerline.

This pull request adds a syntactic segment to powerline. Since the segment isn't merged into the main powerline tree you need to preform the patches by hand. Thankfully you only need to modify three files. (+ means add the line/ - mean remove line). Look at the pull request for a colored diff.

File: powerline/config_files/colorschemes/vim/default.json (Line 28)

     "line_current_symbol": { "fg": "gray1", "bg": "gray10" },
     "virtcol_current_gradient": { "fg": "dark_GREEN_Orange_red", "bg": "gray10" },
     "col_current": { "fg": "gray6", "bg": "gray10" },
-    "modified_buffers": { "fg": "brightyellow", "bg": "gray2" }
+    "modified_buffers": { "fg": "brightyellow", "bg": "gray2" },
+    "syntastic_segment": { "fg": "brightestred", "bg": "gray2", "attr": ["bold"] }
   },
   "mode_translations": {
     "nc": {

---

File: powerline/config_files/colorschemes/vim/default.json (Line 68)

       "groups": {
         "mode": { "fg": "darkestcyan", "bg": "white", "attr": ["bold"] },
         "background:divider": { "fg": "darkcyan", "bg": "darkestblue" },
-        "branch:divider": { "fg": "darkcyan", "bg": "darkblue" }
+        "branch:divider": { "fg": "darkcyan", "bg": "darkblue" },
+        "syntastic_segment": { "fg": "white", "bg": "darkestblue", "attr": ["bold"] }
       }
     },
     "v": {

---

File: powerline/config_files/colorschemes/vim/solarized.json (Line 27)

     "line_current":             { "fg": "gray13", "bg": "lightyellow", "attr": ["bold"] },
     "line_current_symbol":      { "fg": "gray13", "bg": "lightyellow" },
     "virtcol_current_gradient": { "fg": "GREEN_Orange_red", "bg": "gray10" },
-    "col_current":              { "fg": "azure4", "bg": "lightyellow" }
+    "col_current":              { "fg": "azure4", "bg": "lightyellow" },
+    "syntastic_segment":        { "fg": "red", "bg": "royalblue5", "attr": ["bold"] }
   },
   "mode_translations": {
     "nc": {

---

File: powerline/config_files/colorschemes/vim/solarized.json (Line 65)

         "line_percent_gradient":  { "fg": "oldlace", "bg": "gray61" },
         "line_current":           { "fg": "gray13", "bg": "oldlace", "attr": ["bold"] },
         "line_current_symbol":    { "fg": "gray13", "bg": "oldlace" },
-        "col_current":            { "fg": "azure4", "bg": "oldlace" }
+        "col_current":            { "fg": "azure4", "bg": "oldlace" },
+        "syntastic_segment":      { "fg": "lightyellow", "bg": "darkgreencopper", "attr": ["bold"] }
       }
     },
     "v": {

---

File: powerline/segments/vim.py (Line 23)

   'expand': vim_get_func('expand', rettype=str),
   'bufnr': vim_get_func('bufnr', rettype=int),
   'line2byte': vim_get_func('line2byte', rettype=int),
+  'exists': vim_get_func('exists', rettype=int),
 }

 vim_modes = {

---

At the end of powerline/segments/vim.py add the following function. (Make sure you use tabs to indent the function. You are modifying a python file indentation matters)

@window_cached
def syntastic_segment(pl):
    '''Return the syntastic statusline flag
    '''
    if int(vim_funcs['exists']('*SyntasticStatuslineFlag')) > 0:
        syntastic_flag_func = vim_get_func('SyntasticStatuslineFlag', rettype=str)
        return [{
            'contents': str(syntastic_flag_func()),
        }]
    else:
        return None

---

After all these changes are made you need to now turn on the segment. One way to do this is to edit the config file ~/.config/powerline/themes/vim/default.json

In the section segments: place the following in either the right or the left sections.

{
    "name": "syntastic_segment",
    "before": " "
},

After all of these changes you should now be able to see the syntastic error output on the power line segment.

---

Troubleshooting:

• if you introduce parse errors into the json you can start vim up with vim --noplugin to start vim without plugins to powerline doesn't try and parse the file.
• Make sure the commas for the json are in the right places.
• Make sure you used tabs and not spaces in the python files when editing them.