#208 Automatically detect pylint in virtualenv directories

autoload/ale/python.vim

@@ -1,2 +1,29 @@
 " Author: w0rp <devw0rp@gmail.com>
 " Description: Functions for integrating with Python linters.
+
+" Given a buffer number, find the project root directory for Python.
+" The root directory is defined as the first directory found while searching
+" upwards through paths, including the current directory, until a path
+" containing no __init__.py files is found.
+function! ale#python#FindProjectRoot(buffer) abort
+    for l:path in ale#path#Upwards(expand('#' . a:buffer . ':p:h'))
+        if !filereadable(l:path . '/__init__.py')
+            return l:path
+        endif
+    endfor
+
+    return ''
+endfunction
+
+" Given a buffer number, find a virtualenv path for Python.
+function! ale#python#FindVirtualenv(buffer) abort
+    for l:path in ale#path#Upwards(expand('#' . a:buffer . ':p:h'))
+        let l:matches = globpath(l:path, '*/bin/activate', 0, 1)
+
+        if !empty(l:matches)
+            return fnamemodify(l:matches[-1], ':h:h')
+        endif
+    endfor
+
+    return ''
+endfunction