Initial revision

Lib/codehack.py

@@ -0,0 +1,54 @@
+# A subroutine for extracting a function name from a code object
+# (with cache)
+
+import sys
+from stat import *
+import string
+import os
+import linecache
+
+# Extract the function or class name from a code object.
+# This is a bit of a hack, since a code object doesn't contain
+# the name directly.  So what do we do:
+# - get the filename (which *is* in the code object)
+# - look in the code string to find the first SET_LINENO instruction
+#   (this must be the first instruction)
+# - get the line from the file
+# - if the line starts with 'class' or 'def' (after possible whitespace),
+#   extract the following identifier
+#
+# This breaks apart when the function was read from <stdin>
+# or constructed by exec(), when the file is not accessible,
+# and also when the file has been modified or when a line is
+# continued with a backslash before the function or class name.
+#
+# Because this is a pretty expensive hack, a cache is kept.
+
+SET_LINENO = 127 # The opcode (see "opcode.h" in the Python source)
+identchars = string.letters + string.digits + '_' # Identifier characters
+
+_namecache = {} # The cache
+
+def getcodename(co):
+	key = `co` # arbitrary but uniquely identifying string
+	if _namecache.has_key(key): return _namecache[key]
+	filename = co.co_filename
+	code = co.co_code
+	name = ''
+	if ord(code[0]) == SET_LINENO:
+		lineno = ord(code[1]) | ord(code[2]) << 8
+		line = linecache.getline(filename, lineno)
+		words = string.split(line)
+		if len(words) >= 2 and words[0] in ('def', 'class'):
+			name = words[1]
+			for i in range(len(name)):
+				if name[i] not in identchars:
+					name = name[:i]
+					break
+	_namecache[key] = name
+	return name
+
+# Use the above routine to find a function's name.
+
+def getfuncname(func):
+	return getcodename(func.func_code)