diff --git a/support/scripts/graph-depends b/support/scripts/graph-depends
index 07b9c2244..42a42a854 100755
--- a/support/scripts/graph-depends
+++ b/support/scripts/graph-depends
@@ -25,13 +25,9 @@ import sys
 import subprocess
 import argparse
 
-# In FULL_MODE, we draw the full dependency graph for all selected
-# packages
-FULL_MODE = 1
-
-# In PKG_MODE, we only draw the dependency graph for a given package
-PKG_MODE  = 2
-
+# Modes of operation:
+MODE_FULL = 1   # draw full dependency graph for all selected packages
+MODE_PKG  = 2   # draw dependency graph for a given package
 mode = 0
 
 # Limit drawing the dependency graph to this depth. 0 means 'no limit'.
@@ -58,9 +54,9 @@ parser.add_argument("--no-transitive", dest="transitive", action='store_false',
 args = parser.parse_args()
 
 if args.package is None:
-    mode = FULL_MODE
+    mode = MODE_FULL
 else:
-    mode = PKG_MODE
+    mode = MODE_PKG
     rootpkg = args.package
 
 max_depth = args.depth
@@ -183,7 +179,7 @@ TARGET_EXCEPTIONS = [
 
 # In full mode, start with the result of get_targets() to get the main
 # targets and then use get_all_depends() for all targets
-if mode == FULL_MODE:
+if mode == MODE_FULL:
     targets = get_targets()
     dependencies = []
     allpkgs.append('all')
@@ -201,7 +197,7 @@ if mode == FULL_MODE:
 
 # In pkg mode, start directly with get_all_depends() on the requested
 # package
-elif mode == PKG_MODE:
+elif mode == MODE_PKG:
     dependencies = get_all_depends([rootpkg])
 
 # Make the dependencies a dictionnary { 'pkg':[dep1, dep2, ...] }
@@ -269,7 +265,7 @@ def print_attrs(pkg):
         label = 'ALL'
     else:
         label = pkg
-    if pkg == 'all' or (mode == PKG_MODE and pkg == rootpkg):
+    if pkg == 'all' or (mode == MODE_PKG and pkg == rootpkg):
         color = root_colour
     else:
         if pkg.startswith('host') \