# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1309726311 -7200
# Node ID cf329206154e53f92e60057451a3f84a17223f1f
# Parent  af19598efe329ca43827eaecee8e599ddeffc03c
Introduced constant usage tracking.

diff -r af19598efe32 -r cf329206154e TO_DO.txt
--- a/TO_DO.txt	Sun Jul 03 20:11:13 2011 +0200
+++ b/TO_DO.txt	Sun Jul 03 22:51:51 2011 +0200
@@ -137,8 +137,6 @@
 Object Coverage
 ===============
 
-Incorporate constants into the coverage, eliminating unused constants.
-
 Support __init__ traversal (and other implicit names) more effectively.
 
 Other
diff -r af19598efe32 -r cf329206154e micropython/__init__.py
--- a/micropython/__init__.py	Sun Jul 03 20:11:13 2011 +0200
+++ b/micropython/__init__.py	Sun Jul 03 22:51:51 2011 +0200
@@ -376,7 +376,8 @@
         # Constant records.
 
         self.constant_values = {}
-        self.constant_list = None # cache for constants
+        self.constants_used = set()
+        self.constant_references = {}
         self.init_predefined_constants()
 
         # Attribute usage.
@@ -579,6 +580,11 @@
 
         self.attribute_users_visited.add(from_name)
 
+        # Get constant references.
+
+        for const in self.constant_references.get(from_name, []):
+            self.constants_used.add(const)
+
         # The getattr function is a special case: it can potentially reference
         # any known attribute. Since accessor attributes must be known
         # constants, the intersection of known constants and attributes is used
@@ -709,12 +715,24 @@
 
     # Constant accounting.
 
+    def use_constant(self, const, from_name):
+
+        """
+        Register the given 'const' as being used in the program from within an
+        object with the specified 'from_name'.
+        """
+
+        if not self.constant_references.has_key(from_name):
+            self.constant_references[from_name] = set()
+
+        self.constant_references[from_name].add(const)
+
     def init_predefined_constants(self):
 
         "Ensure the predefined constants."
 
         for name, value in self.predefined_constants.items():
-            self.make_constant(value)
+            self.constants_used.add(self.make_constant(value))
 
     def get_predefined_constant(self, name):
 
@@ -750,10 +768,7 @@
 
         "Return a list of constants."
 
-        if self.constant_list is None:
-            self.constant_list = list(self.constant_values.values())
-
-        return self.constant_list
+        return self.constants_used
 
     # Import methods.
 
diff -r af19598efe32 -r cf329206154e micropython/inspect.py
--- a/micropython/inspect.py	Sun Jul 03 20:11:13 2011 +0200
+++ b/micropython/inspect.py	Sun Jul 03 22:51:51 2011 +0200
@@ -345,6 +345,13 @@
             unit = self.get_namespace()
             self.importer.use_name(name, unit.full_name(), value)
 
+    def use_constant(self, const):
+
+        "Use the given 'const' within the current namespace/unit."
+
+        unit = self.get_namespace()
+        self.importer.use_constant(const, unit.full_name())
+
     # Attribute usage methods.
     # These are convenience methods which refer to the specific namespace's
     # implementation of these operations.
@@ -511,7 +518,9 @@
         """
 
         self.use_specific_attribute("__builtins__", self.importer.get_constant_type_name(value))
-        return self.importer.make_constant(value)
+        const = self.importer.make_constant(value)
+        self.use_constant(const)
+        return const
 
     def _visitFunction(self, node, name):