This patch introduces an extra pass to the compiler that generates a symbol table for each top-level compilation unit. The information in the symbol table allows the elimination of the later optimize() pass; the bytecode generation emits the correct opcodes. The current version passes the complete regression test, but may still contain some bugs. It's a fairly substantial revision. The current code adds an assert() and a test that may lead to a Py_FatalError(). I expect to remove these before 2.1 beta 1. The symbol table (struct symtable) is described in comments in the code. The changes affects the several com_XXX() functions that were used to emit LOAD_NAME and its ilk. The primary interface for this bytecode is now com_addop_varname() which takes a kind and a name, where kind is one of VAR_LOAD, VAR_STORE, or VAR_DELETE. There are many other smaller changes: - The name mangling code is no longer contained in ifdefs. There are two functions that expose the mangling logical: com_mangle() and symtable_mangle(). - The com_error() function can accept NULL for its first argument; this is useful with is_constant_false() is called during symbol table generation. - The loop index names used by list comprehensions have been changed from __1__ to [1], so that they can not be accessed by Python code. - in com_funcdef(), com_argdefs() is now called before the body of the function is compiled. This provides consistency with com_lambdef() and symtable_funcdef(). - Helpers do_pad(), dump(), and DUMP() are added to aid in debugging the compiler.