diff --git a/scripts/build.py b/scripts/build.py
index 5faa1a91..8cdb35ea 100644
--- a/scripts/build.py
+++ b/scripts/build.py
@@ -17,34 +17,40 @@ import datetime
 import re
 from os.path import expanduser
 
+class ResultCache(object):
+
+    def __init__(self):
+        self.__cache = {}
+
+    def run(self, func, args):
+        d = self.__cache
+        depth = 0
+        keys = [ func.__name__ ] + args
+        l = len(keys)
+        for k in keys:
+            if k is None:
+                k = 'None'
+            else:
+                k = str(k)
+            depth += 1
+            #debug('depth = ', depth, 'key = ', k, 'd = ', str(d))
+            if k in d:
+                if l == depth:
+                    return d[k]
+                d = d[k]
+                continue
+            if l == depth:
+                r = func(*args)
+                d[k] = r
+                return r
+            d = d[k] = {}
+            #d = d[k]
+        raise Exception("cache algorithm failed for function", func.__name__, "in depth", depth)
+
 def debug(*objs):
     if args.debug:
         print("DEBUG: ", *objs, file=sys.stderr)
 
-def build_cache_func(func, args):
-    global build_cache
-    d = build_cache
-    depth = 0
-    keys = [ func.__name__ ] + args
-    l = len(keys)
-    for k in keys:
-        if k is None:
-            k = 'None'
-        depth += 1
-        #debug('depth = ', depth, 'key = ', k, 'd = ', str(d))
-        if k in d:
-            if l == depth:
-                return d[k]
-            d = d[k]
-            continue
-        if l == depth:
-            r = func(*args)
-            d[k] = r
-            return r
-        d[k] = {}
-        d = d[k]
-    raise Exception("cache algorithm failed for function", func.__name__, "in depth", depth)
-
 def build_find_proj_path(name):
     name=name.replace("dspider-", "")
     search_path=[".", "dspc/src", "dspc/src/dspcd-plugins", "dspc/src/io" ]
@@ -55,10 +61,11 @@ def build_find_proj_path(name):
     raise Exception("module " + name + " not found below " + projs_root)
 
 def build_find_proj_path_cached(name):
-    return build_cache_func(build_find_proj_path, [ name ])
+    return res_cache.run(build_find_proj_path, [ name ])
 
 def build_read_deps(cur, prereq_type):
     # dep cache doesn't make a difference at all
+    projects_py="/usr/bin/python2 " + my_dir + "/projects.py --prefix " + projs_root + " " + os.getenv('PROJECTS_PY_EXTRA_ARGS', "")
     if prereq_type in dep_cache:
         if cur in dep_cache[prereq_type]:
             return dep_cache[prereq_type][cur]
@@ -85,7 +92,7 @@ def build_read_deps(cur, prereq_type):
     return r
 
 def build_read_deps_cached(cur, prereq_type):
-    return build_cache_func(build_read_deps, [ cur, prereq_type ])
+    return res_cache.run(build_read_deps, [ cur, prereq_type ])
 
 def build_add_dep_tree(cur, prereq_types, tree, all_deps):
     debug("adding prerequisites " + ' '.join(prereq_types) + " of module " + cur)
@@ -225,7 +232,7 @@ def cmd_build(args_):
 # -------------------------------------------------------------------- here we go
 
 global_args = []
-#cache = ResultCache()
+#res_cache = ResultCache()
 
 skip = 0
 for a in sys.argv[1::]:
@@ -255,18 +262,15 @@ args=parser.parse_args(global_args)
 debug("----------------------------------------- running ", ' '.join(sys.argv))
 
 projs_root = args.prefix
+res_cache = ResultCache()
+dep_cache = {}
+my_dir=os.path.dirname(os.path.realpath(__file__))
 
 if args.topdir:
     topdir = args.topdir
-    top_name = cache.run(read_value, [topdir + '/make/project.conf', 'build', 'name'])
+    top_name = res_cache.run(read_value, [topdir + '/make/project.conf', 'build', 'name'])
     if not top_name:
         top_name = re.sub('-[0-9.-]*$', '', basename(realpath(topdir)))
 
-# ---- global variables
-build_cache = {}
-dep_cache = {}
-my_dir=os.path.dirname(os.path.realpath(__file__))
-projects_py="/usr/bin/python2 " + my_dir + "/projects.py --prefix " + projs_root + " " + os.getenv('PROJECTS_PY_EXTRA_ARGS', "")
-
 cmd = getattr(sys.modules[__name__], 'cmd_' + args.cmd.replace('-', '_'))
 cmd(sys.argv[(len(global_args) + 1)::])
diff --git a/scripts/projects.py b/scripts/projects.py
index 7fd6ccbb..1add916e 100644
--- a/scripts/projects.py
+++ b/scripts/projects.py
@@ -1,6 +1,7 @@
 #!/usr/bin/python2 -u
 
 from __future__ import print_function
+import os
 import sys
 import argparse
 from sets import Set
@@ -100,7 +101,7 @@ def htdocs_dir(name):
 
 def os_cascade():
     r = [ 'os', platform.system().lower() ]
-    os = cache.run(get_os, [])
+    os = res_cache.run(get_os, [])
     name = re.sub('-.*', '', os)
     series = os
     while True:
@@ -190,7 +191,7 @@ def get_value(name, section, key):
 
     path = proj_root + '/make/project.conf'
     #print('path = ', path, 'top_name = ', top_name, 'name = ', name)
-    return cache.run(read_value, [path, section, key])
+    return res_cache.run(read_value, [path, section, key])
 
 def collect_values(names, section, key):
     r = ""
@@ -206,7 +207,7 @@ def collect_values(names, section, key):
 
 def add_modules_from_project_txt_cached(buf, visited, spec, section, key, add_self, scope,
         names_only):
-    return cache.run(add_modules_from_project_txt, [buf, visited, spec, section, key,
+    return res_cache.run(add_modules_from_project_txt, [buf, visited, spec, section, key,
         add_self, scope, names_only])
 
 def add_modules_from_project_txt(buf, visited, spec, section, key, add_self, scope,
@@ -606,7 +607,9 @@ def cmd_getval(args_):
 # -------------------------------------------------------------------- here we go
 
 global_args = []
-cache = ResultCache()
+res_cache = ResultCache()
+dep_cache = {}
+my_dir = os.path.dirname(os.path.realpath(__file__))
 
 skip = 0
 for a in sys.argv[1::]: