Simplify adding mbuild to PYTHONPATH

pysrc/codegen.py

@@ -26,17 +26,8 @@
 import datetime
 
 from genutil import *
-def find_dir(d):
-    directory = os.getcwd()
-    last = ''
-    while directory != last:
-        target_directory = os.path.join(directory,d)
-        if os.path.exists(target_directory):
-            return target_directory
-        last = directory
-        directory = os.path.split(directory)[0]
-    return None
-sys.path.append(find_dir('mbuild'))
+
+add_mbuild_to_path()
 try:
    import mbuild
 except:

pysrc/enumer.py

@@ -22,18 +22,9 @@
 import sys
 import re
 import codegen
+from genutil import add_mbuild_to_path
 
-def find_dir(d):
-    directory = os.getcwd()
-    last = ''
-    while directory != last:
-        target_dir = os.path.join(directory,d)
-        if os.path.exists(target_dir):
-            return target_dir
-        last = directory
-        directory = os.path.split(directory)[0]
-    return None
-sys.path.append(find_dir('mbuild'))
+add_mbuild_to_path()
 try:
    import mbuild
 except:

pysrc/generator.py

@@ -66,22 +66,9 @@
 import optparse
 import collections
 from typing import Dict, List
+from genutil import add_mbuild_to_path
 
-def find_dir(d):
-    directory = os.getcwd()
-    last = ''
-    while directory != last:
-        target_directory = os.path.join(directory,d)
-        if os.path.exists(target_directory):
-            return target_directory
-        last = directory
-        directory = os.path.split(directory)[0]
-    return None
-
-mbuild_install_path = os.path.join(os.path.dirname(sys.argv[0]), '..', 'mbuild')
-if not os.path.exists(mbuild_install_path):
-    mbuild_install_path =  find_dir('mbuild')
-sys.path=  [mbuild_install_path]  + sys.path
+add_mbuild_to_path()
 try:
    import mbuild
 except:

pysrc/genutil.py

@@ -25,7 +25,7 @@
 import re
 import stat
 import platform
-from typing import Tuple, Any, List, Dict
+from typing import Tuple, Any, List, Dict, Optional
 
 psystem = platform.system()
 if (psystem == 'Microsoft' or
@@ -84,6 +84,33 @@ def warn(msg: str):
     msgerr('[WARNING] ' + msg)
 
 
+def find_dir(d: str) -> Optional[str]:
+    """Attempts to find directory `d` in the current directory or any parent directory."""
+
+    directory = os.getcwd()
+    last = ''
+    while directory != last:
+        target_directory = os.path.join(directory, d)
+        if os.path.exists(target_directory):
+            return target_directory
+        last = directory
+        directory = os.path.split(directory)[0]
+    return None
+
+
+def add_mbuild_to_path():
+    """
+    Add the mbuild directory to the python path.
+
+    This will do nothing if `mbuild` already exists in the python path.
+    """
+
+    if not any('mbuild' in x for x in sys.path):
+        mbuild_dir = find_dir('mbuild')
+        if not mbuild_dir:
+            die('Could not find mbuild directory.')
+        sys.path.append(mbuild_dir)
+
 def check_python_version(argmaj: int, argmin: int):
     tup = sys.version_info
     major: int = tup[0]

pysrc/read-encfile.py

@@ -42,24 +42,9 @@
 import optparse
 import stat
 import copy
+from genutil import add_mbuild_to_path
 
-def find_dir(d):
-    directory = os.getcwd()
-    last = ''
-    while directory != last:
-        target_directory = os.path.join(directory,d)
-        if os.path.exists(target_directory):
-            return target_directory
-        last = directory
-        directory = os.path.split(directory)[0]
-    return None
-
-mbuild_install_path = os.path.join(os.path.dirname(sys.argv[0]), 
-                                   '..', '..', 'mbuild')
-
-if not os.path.exists(mbuild_install_path):
-    mbuild_install_path =  find_dir('mbuild')
-sys.path=  [mbuild_install_path]  + sys.path
+add_mbuild_to_path()
 try:
    import mbuild
 except: