path: root/Cython/Compiler/Symtab.py

#
#   Symbol Table
#

import re
from Cython import Utils
from Errors import warning, error, InternalError
from StringEncoding import EncodedString
import Options, Naming
import PyrexTypes
from PyrexTypes import py_object_type, unspecified_type
import TypeSlots
from TypeSlots import \
    pyfunction_signature, pymethod_signature, \
    get_special_method_signature, get_property_accessor_signature
import ControlFlow
import Code
import __builtin__ as builtins
try:
    set
except NameError:
    from sets import Set as set

possible_identifier = re.compile(ur"(?![0-9])\w+$", re.U).match
nice_identifier = re.compile('^[a-zA-Z0-0_]+$').match

iso_c99_keywords = set(
['auto', 'break', 'case', 'char', 'const', 'continue', 'default', 'do', 
    'double', 'else', 'enum', 'extern', 'float', 'for', 'goto', 'if', 
    'int', 'long', 'register', 'return', 'short', 'signed', 'sizeof', 
    'static', 'struct', 'switch', 'typedef', 'union', 'unsigned', 'void', 
    'volatile', 'while',
    '_Bool', '_Complex'', _Imaginary', 'inline', 'restrict'])

def c_safe_identifier(cname):
    # There are some C limitations on struct entry names.
    if ((cname[:2] == '__'
         and not (cname.startswith(Naming.pyrex_prefix)
                  or cname == '__weakref__'))
        or cname in iso_c99_keywords):
        cname = Naming.pyrex_prefix + cname
    return cname

class BufferAux(object):
    writable_needed = False
    
    def __init__(self, buflocal_nd_var, rcbuf_var):
        self.buflocal_nd_var = buflocal_nd_var
        self.rcbuf_var = rcbuf_var
        
    def __repr__(self):
        return "<BufferAux %r>" % self.__dict__

class Entry(object):
    # A symbol table entry in a Scope or ModuleNamespace.
    #
    # name             string     Python name of entity
    # cname            string     C name of entity
    # type             PyrexType  Type of entity
    # doc              string     Doc string
    # init             string     Initial value
    # visibility       'private' or 'public' or 'extern'
    # is_builtin       boolean    Is an entry in the Python builtins dict
    # is_cglobal       boolean    Is a C global variable
    # is_pyglobal      boolean    Is a Python module-level variable
    #                               or class attribute during
    #                               class construction
    # is_member        boolean    Is an assigned class member
    # is_variable      boolean    Is a variable
    # is_cfunction     boolean    Is a C function
    # is_cmethod       boolean    Is a C method of an extension type
    # is_unbound_cmethod boolean  Is an unbound C method of an extension type
    # is_type          boolean    Is a type definition
    # is_cclass        boolean    Is an extension class
    # is_const         boolean    Is a constant
    # is_property      boolean    Is a property of an extension type:
    # doc_cname        string or None  C const holding the docstring
    # getter_cname     string          C func for getting property
    # setter_cname     string          C func for setting or deleting property
    # is_self_arg      boolean    Is the "self" arg of an exttype method
    # is_arg           boolean    Is the arg of a method
    # is_local         boolean    Is a local variable
    # in_closure       boolean    Is referenced in an inner scope
    # is_readonly      boolean    Can't be assigned to
    # func_cname       string     C func implementing Python func
    # func_modifiers   [string]   C function modifiers ('inline')
    # pos              position   Source position where declared
    # namespace_cname  string     If is_pyglobal, the C variable
    #                               holding its home namespace
    # pymethdef_cname  string     PyMethodDef structure
    # signature        Signature  Arg & return types for Python func
    # init_to_none     boolean    True if initial value should be None
    # as_variable      Entry      Alternative interpretation of extension
    #                               type name or builtin C function as a variable
    # xdecref_cleanup  boolean    Use Py_XDECREF for error cleanup
    # in_cinclude      boolean    Suppress C declaration code
    # enum_values      [Entry]    For enum types, list of values
    # qualified_name   string     "modname.funcname" or "modname.classname"
    #                               or "modname.classname.funcname"
    # is_declared_generic  boolean  Is declared as PyObject * even though its
    #                                 type is an extension type
    # as_module        None       Module scope, if a cimported module
    # is_inherited     boolean    Is an inherited attribute of an extension type
    # pystring_cname   string     C name of Python version of string literal
    # is_interned      boolean    For string const entries, value is interned
    # is_identifier    boolean    For string const entries, value is an identifier
    # used             boolean
    # is_special       boolean    Is a special method or property accessor
    #                               of an extension type
    # defined_in_pxd   boolean    Is defined in a .pxd file (not just declared)
    # api              boolean    Generate C API for C class or function
    # utility_code     string     Utility code needed when this entry is used
    #
    # buffer_aux       BufferAux or None  Extra information needed for buffer variables
    # inline_func_in_pxd boolean  Hacky special case for inline function in pxd file.
    #                             Ideally this should not be necesarry.
    # assignments      [ExprNode] List of expressions that get assigned to this entry.
    # utility_code_definition     For some Cython builtins, the utility code
    #                             which contains the definition of the entry.
    #                             Currently only supported for CythonScope entries.

    # TODO: utility_code and utility_code_definition serves the same purpose...

    inline_func_in_pxd = False
    borrowed = 0
    init = ""
    visibility = 'private'
    is_builtin = 0
    is_cglobal = 0
    is_pyglobal = 0
    is_member = 0
    is_variable = 0
    is_cfunction = 0
    is_cmethod = 0
    is_unbound_cmethod = 0
    is_type = 0
    is_cclass = 0
    is_const = 0
    is_property = 0
    doc_cname = None
    getter_cname = None
    setter_cname = None
    is_self_arg = 0
    is_arg = 0
    is_local = 0
    in_closure = 0
    is_declared_generic = 0
    is_readonly = 0
    func_cname = None
    func_modifiers = []
    doc = None
    init_to_none = 0
    as_variable = None
    xdecref_cleanup = 0
    in_cinclude = 0
    as_module = None
    is_inherited = 0
    pystring_cname = None
    is_identifier = 0
    is_interned = 0
    used = 0
    is_special = 0
    defined_in_pxd = 0
    is_implemented = 0
    api = 0
    utility_code = None
    is_overridable = 0
    buffer_aux = None
    prev_entry = None
    utility_code_definition = None

    def __init__(self, name, cname, type, pos = None, init = None):
        self.name = name
        self.cname = cname
        self.type = type
        self.pos = pos
        self.init = init
        self.assignments = []
    
    def __repr__(self):
        return "Entry(name=%s, type=%s)" % (self.name, self.type)
        
    def redeclared(self, pos):
        error(pos, "'%s' does not match previous declaration" % self.name)
        error(self.pos, "Previous declaration is here")

class Scope(object):
    # name              string             Unqualified name
    # outer_scope       Scope or None      Enclosing scope
    # entries           {string : Entry}   Python name to entry, non-types
    # const_entries     [Entry]            Constant entries
    # type_entries      [Entry]            Struct/union/enum/typedef/exttype entries
    # sue_entries       [Entry]            Struct/union/enum entries
    # arg_entries       [Entry]            Function argument entries
    # var_entries       [Entry]            User-defined variable entries
    # pyfunc_entries    [Entry]            Python function entries
    # cfunc_entries     [Entry]            C function entries
    # c_class_entries   [Entry]            All extension type entries
    # cname_to_entry    {string : Entry}   Temp cname to entry mapping
    # return_type       PyrexType or None  Return type of function owning scope
    # is_py_class_scope boolean            Is a Python class scope
    # is_c_class_scope  boolean            Is an extension type scope
    # scope_prefix      string             Disambiguator for C names
    # in_cinclude       boolean            Suppress C declaration code
    # qualified_name    string             "modname" or "modname.classname"
    #                                        Python strings in this scope
    # control_flow     ControlFlow  Used for keeping track of environment state
    # nogil             boolean            In a nogil section
    # directives       dict                Helper variable for the recursive
    #                                      analysis, contains directive values.

    is_py_class_scope = 0
    is_c_class_scope = 0
    is_module_scope = 0
    scope_prefix = ""
    in_cinclude = 0
    nogil = 0
    
    def __init__(self, name, outer_scope, parent_scope):
        # The outer_scope is the next scope in the lookup chain.
        # The parent_scope is used to derive the qualified name of this scope.
        self.name = name
        self.outer_scope = outer_scope
        self.parent_scope = parent_scope
        mangled_name = "%d%s_" % (len(name), name)
        qual_scope = self.qualifying_scope()
        if qual_scope:
            self.qualified_name = qual_scope.qualify_name(name)
            self.scope_prefix = qual_scope.scope_prefix + mangled_name
        else:
            self.qualified_name = name
            self.scope_prefix = mangled_name
        self.entries = {}
        self.const_entries = []
        self.type_entries = []
        self.sue_entries = []
        self.arg_entries = []
        self.var_entries = []
        self.pyfunc_entries = []
        self.cfunc_entries = []
        self.c_class_entries = []
        self.defined_c_classes = []
        self.imported_c_classes = {}
        self.cname_to_entry = {}
        self.string_to_entry = {}
        self.identifier_to_entry = {}
        self.num_to_entry = {}
        self.obj_to_entry = {}
        self.buffer_entries = []
        self.control_flow = ControlFlow.LinearControlFlow()
        self.return_type = None

    def merge_in(self, other):
        # Use with care...
        self.entries.update(other.entries)
        for x in ('const_entries',
                  'type_entries',
                  'sue_entries',
                  'arg_entries',
                  'var_entries',
                  'pyfunc_entries',
                  'cfunc_entries',
                  'c_class_entries'):
            getattr(self, x).extend(getattr(other, x))

    def start_branching(self, pos):
        self.control_flow = self.control_flow.start_branch(pos)
    
    def next_branch(self, pos):
        self.control_flow = self.control_flow.next_branch(pos)
        
    def finish_branching(self, pos):
        self.control_flow = self.control_flow.finish_branch(pos)
        
    def __str__(self):
        return "<%s %s>" % (self.__class__.__name__, self.qualified_name)

    def qualifying_scope(self):
        return self.parent_scope
    
    def mangle(self, prefix, name = None):
        if name:
            return "%s%s%s" % (prefix, self.scope_prefix, name)
        else:
            return self.parent_scope.mangle(prefix, self.name)
    
    def mangle_internal(self, name):
        # Mangle an internal name so as not to clash with any
        # user-defined name in this scope.
        prefix = "%s%s_" % (Naming.pyrex_prefix, name)
        return self.mangle(prefix)
        #return self.parent_scope.mangle(prefix, self.name)
    
    def global_scope(self):
        # Return the module-level scope containing this scope.
        return self.outer_scope.global_scope()
    
    def builtin_scope(self):
        # Return the module-level scope containing this scope.
        return self.outer_scope.builtin_scope()

    def declare(self, name, cname, type, pos, visibility):
        # Create new entry, and add to dictionary if
        # name is not None. Reports a warning if already 
        # declared.
        if not self.in_cinclude and cname and re.match("^_[_A-Z]+$", cname):
            # See http://www.gnu.org/software/libc/manual/html_node/Reserved-Names.html#Reserved-Names 
            warning(pos, "'%s' is a reserved name in C." % cname, -1)
        entries = self.entries
        if name and name in entries:
            if visibility == 'extern':
                warning(pos, "'%s' redeclared " % name, 0)
            elif visibility != 'ignore':
                error(pos, "'%s' redeclared " % name)
        entry = Entry(name, cname, type, pos = pos)
        entry.in_cinclude = self.in_cinclude
        if name:
            entry.qualified_name = self.qualify_name(name)
            entries[name] = entry
        entry.scope = self
        entry.visibility = visibility
        return entry
    
    def qualify_name(self, name):
        return "%s.%s" % (self.qualified_name, name)

    def declare_const(self, name, type, value, pos, cname = None, visibility = 'private'):
        # Add an entry for a named constant.
        if not cname:
            if self.in_cinclude or visibility == 'public':
                cname = name
            else:
                cname = self.mangle(Naming.enum_prefix, name)
        entry = self.declare(name, cname, type, pos, visibility)
        entry.is_const = 1
        entry.value_node = value
        return entry
    
    def declare_type(self, name, type, pos, 
            cname = None, visibility = 'private', defining = 1):
        # Add an entry for a type definition.
        if not cname:
            cname = name
        entry = self.declare(name, cname, type, pos, visibility)
        entry.is_type = 1
        if defining:
            self.type_entries.append(entry)
        # here we would set as_variable to an object representing this type
        return entry
    
    def declare_typedef(self, name, base_type, pos, cname = None,
            visibility = 'private'):
        if not cname:
            if self.in_cinclude or visibility == 'public':
                cname = name
            else:
                cname = self.mangle(Naming.type_prefix, name)
        try:
            type = PyrexTypes.create_typedef_type(cname, base_type, (visibility == 'extern'))
        except ValueError, e:
            error(pos, e.message)
            type = PyrexTypes.error_type
        entry = self.declare_type(name, type, pos, cname, visibility)
        type.qualified_name = entry.qualified_name
        return entry
        
    def declare_struct_or_union(self, name, kind, scope, 
            typedef_flag, pos, cname = None, visibility = 'private',
            packed = False):
        # Add an entry for a struct or union definition.
        if not cname:
            if self.in_cinclude or visibility == 'public':
                cname = name
            else:
                cname = self.mangle(Naming.type_prefix, name)
        entry = self.lookup_here(name)
        if not entry:
            type = PyrexTypes.CStructOrUnionType(
                name, kind, scope, typedef_flag, cname, packed)
            entry = self.declare_type(name, type, pos, cname,
                visibility = visibility, defining = scope is not None)
            self.sue_entries.append(entry)
            type.entry = entry
        else:
            if not (entry.is_type and entry.type.is_struct_or_union
                    and entry.type.kind == kind):
                warning(pos, "'%s' redeclared  " % name, 0)
            elif scope and entry.type.scope:
                warning(pos, "'%s' already defined  (ignoring second definition)" % name, 0)
            else:
                self.check_previous_typedef_flag(entry, typedef_flag, pos)
                self.check_previous_visibility(entry, visibility, pos)
                if scope:
                    entry.type.scope = scope
                    self.type_entries.append(entry)
        if not scope and not entry.type.scope:
            self.check_for_illegal_incomplete_ctypedef(typedef_flag, pos)
        return entry
    
    def check_previous_typedef_flag(self, entry, typedef_flag, pos):
        if typedef_flag != entry.type.typedef_flag:
            error(pos, "'%s' previously declared using '%s'" % (
                entry.name, ("cdef", "ctypedef")[entry.type.typedef_flag]))
    
    def check_previous_visibility(self, entry, visibility, pos):
        if entry.visibility != visibility:
            error(pos, "'%s' previously declared as '%s'" % (
                entry.name, entry.visibility))
    
    def declare_enum(self, name, pos, cname, typedef_flag,
            visibility = 'private'):
        if name:
            if not cname:
                if self.in_cinclude or visibility == 'public':
                    cname = name
                else:
                    cname = self.mangle(Naming.type_prefix, name)
            type = PyrexTypes.CEnumType(name, cname, typedef_flag)
        else:
            type = PyrexTypes.c_anon_enum_type
        entry = self.declare_type(name, type, pos, cname = cname,
            visibility = visibility)
        entry.enum_values = []
        self.sue_entries.append(entry)
        return entry    
    
    def declare_var(self, name, type, pos, 
            cname = None, visibility = 'private', is_cdef = 0):
        # Add an entry for a variable.
        if not cname:
            if visibility != 'private':
                cname = name
            else:
                cname = self.mangle(Naming.var_prefix, name)
        entry = self.declare(name, cname, type, pos, visibility)
        entry.is_variable = 1
        self.control_flow.set_state((), (name, 'initalized'), False)
        return entry
        
    def declare_builtin(self, name, pos):
        return self.outer_scope.declare_builtin(name, pos)
    
    def declare_pyfunction(self, name, pos):
        # Add an entry for a Python function.
        entry = self.lookup_here(name)
        if entry and not entry.type.is_cfunction:
            # This is legal Python, but for now will produce invalid C.
            error(pos, "'%s' already declared" % name)
        entry = self.declare_var(name, py_object_type, pos, visibility='extern')
        entry.signature = pyfunction_signature
        self.pyfunc_entries.append(entry)
        return entry
    
    def register_pyfunction(self, entry):
        self.pyfunc_entries.append(entry)
    
    def declare_cfunction(self, name, type, pos, 
                          cname = None, visibility = 'private', defining = 0,
                          api = 0, in_pxd = 0, modifiers = ()):
        # Add an entry for a C function.
        entry = self.lookup_here(name)
        if entry:
            if visibility != 'private' and visibility != entry.visibility:
                warning(pos, "Function '%s' previously declared as '%s'" % (name, entry.visibility), 1)
            if not entry.type.same_as(type):
                if visibility == 'extern' and entry.visibility == 'extern':
                    warning(pos, "Function signature does not match previous declaration", 1)
                    entry.type = type
                else:
                    error(pos, "Function signature does not match previous declaration")
        else:
            if not cname:
                if api or visibility != 'private':
                    cname = name
                else:
                    cname = self.mangle(Naming.func_prefix, name)
            entry = self.add_cfunction(name, type, pos, cname, visibility, modifiers)
            entry.func_cname = cname
        if in_pxd and visibility != 'extern':
            entry.defined_in_pxd = 1
        if api:
            entry.api = 1
        if not defining and not in_pxd and visibility != 'extern':
            error(pos, "Non-extern C function '%s' declared but not defined" % name)
        if defining:
            entry.is_implemented = True
        if modifiers:
            entry.func_modifiers = modifiers
        return entry
    
    def add_cfunction(self, name, type, pos, cname, visibility, modifiers):
        # Add a C function entry without giving it a func_cname.
        entry = self.declare(name, cname, type, pos, visibility)
        entry.is_cfunction = 1
        if modifiers:
            entry.func_modifiers = modifiers
        self.cfunc_entries.append(entry)
        return entry
    
    def find(self, name, pos):
        # Look up name, report error if not found.
        entry = self.lookup(name)
        if entry:
            return entry
        else:
            error(pos, "'%s' is not declared" % name)
    
    def find_imported_module(self, path, pos):
        # Look up qualified name, must be a module, report error if not found.
        # Path is a list of names.
        scope = self
        for name in path:
            entry = scope.find(name, pos)
            if not entry:
                return None
            if entry.as_module:
                scope = entry.as_module
            else:
                error(pos, "'%s' is not a cimported module" % '.'.join(path))
                return None
        return scope
        
    def lookup(self, name):
        # Look up name in this scope or an enclosing one.
        # Return None if not found.
        return (self.lookup_here(name)
            or (self.outer_scope and self.outer_scope.lookup_from_inner(name))
            or None)

    def lookup_from_inner(self, name):
        # Look up name in this scope or an enclosing one.
        # This is only called from enclosing scopes.
        return (self.lookup_here(name)
            or (self.outer_scope and self.outer_scope.lookup_from_inner(name))
            or None)

    def lookup_here(self, name):
        # Look up in this scope only, return None if not found.
        return self.entries.get(name, None)
        
    def lookup_target(self, name):
        # Look up name in this scope only. Declare as Python
        # variable if not found.
        entry = self.lookup_here(name)
        if not entry:
            entry = self.declare_var(name, py_object_type, None)
        return entry
        
    def lookup_type(self, name):
        entry = self.lookup(name)
        if entry and entry.is_type:
            return entry.type

    def use_utility_code(self, new_code):
        self.global_scope().use_utility_code(new_code)

    def generate_library_function_declarations(self, code):
        # Generate extern decls for C library funcs used.
        pass
        
    def defines_any(self, names):
        # Test whether any of the given names are
        # defined in this scope.
        for name in names:
            if name in self.entries:    
                return 1
        return 0
    
    def infer_types(self):
        from TypeInference import get_type_inferer
        get_type_inferer().infer_types(self)

class PreImportScope(Scope):

    namespace_cname = Naming.preimport_cname

    def __init__(self):
        Scope.__init__(self, Options.pre_import, None, None)
        
    def declare_builtin(self, name, pos):
        entry = self.declare(name, name, py_object_type, pos, 'private')
        entry.is_variable = True
        entry.is_pyglobal = True
        return entry


class BuiltinScope(Scope):
    #  The builtin namespace.
    
    def __init__(self):
        if Options.pre_import is None:
            Scope.__init__(self, "__builtin__", None, None)
        else:
            Scope.__init__(self, "__builtin__", PreImportScope(), None)
        self.type_names = {}
        
        for name, definition in self.builtin_entries.iteritems():
            cname, type = definition
            self.declare_var(name, type, None, cname)
        
    def declare_builtin(self, name, pos):
        if not hasattr(builtins, name):
            if self.outer_scope is not None:
                return self.outer_scope.declare_builtin(name, pos)
            else:
                error(pos, "undeclared name not builtin: %s"%name)
    
    def declare_builtin_cfunction(self, name, type, cname, python_equiv = None,
            utility_code = None):
        # If python_equiv == "*", the Python equivalent has the same name
        # as the entry, otherwise it has the name specified by python_equiv.
        name = EncodedString(name)
        entry = self.declare_cfunction(name, type, None, cname, visibility='extern')
        entry.utility_code = utility_code
        if python_equiv:
            if python_equiv == "*":
                python_equiv = name
            else:
                python_equiv = EncodedString(python_equiv)
            var_entry = Entry(python_equiv, python_equiv, py_object_type)
            var_entry.is_variable = 1
            var_entry.is_builtin = 1
            entry.as_variable = var_entry
        return entry
        
    def declare_builtin_type(self, name, cname, utility_code = None):
        name = EncodedString(name)
        type = PyrexTypes.BuiltinObjectType(name, cname)
        type.set_scope(CClassScope(name, outer_scope=None, visibility='extern'))
        self.type_names[name] = 1
        entry = self.declare_type(name, type, None, visibility='extern')

        var_entry = Entry(name = entry.name,
            type = self.lookup('type').type, # make sure "type" is the first type declared...
            pos = entry.pos,
            cname = "((PyObject*)%s)" % entry.type.typeptr_cname)
        var_entry.is_variable = 1
        var_entry.is_cglobal = 1
        var_entry.is_readonly = 1
        var_entry.is_builtin = 1
        var_entry.utility_code = utility_code
        entry.as_variable = var_entry

        return type

    def builtin_scope(self):
        return self

    builtin_entries = {

        "type":   ["((PyObject*)&PyType_Type)", py_object_type],

        "bool":   ["((PyObject*)&PyBool_Type)", py_object_type],
        "int":    ["((PyObject*)&PyInt_Type)", py_object_type],
        "long":   ["((PyObject*)&PyLong_Type)", py_object_type],
        "float":  ["((PyObject*)&PyFloat_Type)", py_object_type],
        "complex":["((PyObject*)&PyComplex_Type)", py_object_type],

        "bytes":  ["((PyObject*)&PyBytes_Type)", py_object_type],
        "str":    ["((PyObject*)&PyString_Type)", py_object_type],
        "unicode":["((PyObject*)&PyUnicode_Type)", py_object_type],

        "tuple":  ["((PyObject*)&PyTuple_Type)", py_object_type],
        "list":   ["((PyObject*)&PyList_Type)", py_object_type],
        "dict":   ["((PyObject*)&PyDict_Type)", py_object_type],
        "set":    ["((PyObject*)&PySet_Type)", py_object_type],
        "frozenset":   ["((PyObject*)&PyFrozenSet_Type)", py_object_type],

        "slice":  ["((PyObject*)&PySlice_Type)", py_object_type],
        "file":   ["((PyObject*)&PyFile_Type)", py_object_type],

        "None":   ["Py_None", py_object_type],
        "False":  ["Py_False", py_object_type],
        "True":   ["Py_True", py_object_type],
    }

const_counter = 1 # As a temporary solution for compiling code in pxds

class ModuleScope(Scope):
    # module_name          string             Python name of the module
    # module_cname         string             C name of Python module object
    # #module_dict_cname   string             C name of module dict object
    # method_table_cname   string             C name of method table
    # doc                  string             Module doc string
    # doc_cname            string             C name of module doc string
    # utility_code_list    [UtilityCode]      Queuing utility codes for forwarding to Code.py
    # python_include_files [string]           Standard  Python headers to be included
    # include_files        [string]           Other C headers to be included
    # string_to_entry      {string : Entry}   Map string const to entry
    # identifier_to_entry  {string : Entry}   Map identifier string const to entry
    # context              Context
    # parent_module        Scope              Parent in the import namespace
    # module_entries       {string : Entry}   For cimport statements
    # type_names           {string : 1}       Set of type names (used during parsing)
    # included_files       [string]           Cython sources included with 'include'
    # pxd_file_loaded      boolean            Corresponding .pxd file has been processed
    # cimported_modules    [ModuleScope]      Modules imported with cimport
    # types_imported       {PyrexType : 1}    Set of types for which import code generated
    # has_import_star      boolean            Module contains import *
    
    is_module_scope = 1
    has_import_star = 0

    def __init__(self, name, parent_module, context, no_outer_scope=False):
        self.parent_module = parent_module
        if not no_outer_scope:
            outer_scope = context.find_submodule("__builtin__")
            self.type_names = dict(outer_scope.type_names)
        else:
            outer_scope = None
        Scope.__init__(self, name, outer_scope, parent_module)
        if name != "__init__":
            self.module_name = name
        else:
            # Treat Spam/__init__.pyx specially, so that when Python loads
            # Spam/__init__.so, initSpam() is defined.
            self.module_name = parent_module.module_name
        self.context = context
        self.module_cname = Naming.module_cname
        self.module_dict_cname = Naming.moddict_cname
        self.method_table_cname = Naming.methtable_cname
        self.doc = ""
        self.doc_cname = Naming.moddoc_cname
        self.utility_code_list = []
        self.module_entries = {}
        self.python_include_files = ["Python.h", "structmember.h"]
        self.include_files = []
        self.pxd_file_loaded = 0
        self.cimported_modules = []
        self.types_imported = {}
        self.included_files = []
        self.has_extern_class = 0
        self.cached_builtins = []
        self.undeclared_cached_builtins = []
        self.namespace_cname = self.module_cname
        for name in ['__builtins__', '__name__', '__file__', '__doc__']:
            self.declare_var(EncodedString(name), py_object_type, None)
    
    def qualifying_scope(self):
        return self.parent_module
    
    def global_scope(self):
        return self
    
    def declare_builtin(self, name, pos):
        if not hasattr(builtins, name) and name != 'xrange':
            # 'xrange' is special cased in Code.py
            if self.has_import_star:
                entry = self.declare_var(name, py_object_type, pos)
                return entry
            elif self.outer_scope is not None:
                return self.outer_scope.declare_builtin(name, pos)
            else:
                error(pos, "undeclared name not builtin: %s"%name)
        if Options.cache_builtins:
            for entry in self.cached_builtins:
                if entry.name == name:
                    return entry
        entry = self.declare(None, None, py_object_type, pos, 'private')
        if Options.cache_builtins:
            entry.is_builtin = 1
            entry.is_const = 1
            entry.name = name
            entry.cname = Naming.builtin_prefix + name
            self.cached_builtins.append(entry)
            self.undeclared_cached_builtins.append(entry)
        else:
            entry.is_builtin = 1
        return entry

    def find_module(self, module_name, pos):
        # Find a module in the import namespace, interpreting
        # relative imports relative to this module's parent.
        # Finds and parses the module's .pxd file if the module
        # has not been referenced before.
        return self.global_scope().context.find_module(
            module_name, relative_to = self.parent_module, pos = pos)
    
    def find_submodule(self, name):
        # Find and return scope for a submodule of this module,
        # creating a new empty one if necessary. Doesn't parse .pxd.
        scope = self.lookup_submodule(name)
        if not scope:
            scope = ModuleScope(name, 
                parent_module = self, context = self.context)
            self.module_entries[name] = scope
        return scope
    
    def lookup_submodule(self, name):
        # Return scope for submodule of this module, or None.
        return self.module_entries.get(name, None)
    
    def add_include_file(self, filename):
        if filename not in self.python_include_files \
            and filename not in self.include_files:
                self.include_files.append(filename)
    
    def add_imported_module(self, scope):
        if scope not in self.cimported_modules:
            for filename in scope.include_files:
                self.add_include_file(filename)
            self.cimported_modules.append(scope)
            for m in scope.cimported_modules:
                self.add_imported_module(m)
    
    def add_imported_entry(self, name, entry, pos):
        if entry not in self.entries:
            self.entries[name] = entry
        else:
            warning(pos, "'%s' redeclared  " % name, 0)
    
    def declare_module(self, name, scope, pos):
        # Declare a cimported module. This is represented as a
        # Python module-level variable entry with a module
        # scope attached to it. Reports an error and returns
        # None if previously declared as something else.
        entry = self.lookup_here(name)
        if entry:
            if entry.is_pyglobal and entry.as_module is scope:
                return entry # Already declared as the same module
            if not (entry.is_pyglobal and not entry.as_module):
                # SAGE -- I put this here so Pyrex
                # cimport's work across directories.
                # Currently it tries to multiply define
                # every module appearing in an import list.
                # It shouldn't be an error for a module
                # name to appear again, and indeed the generated
                # code compiles fine. 
                return entry
                warning(pos, "'%s' redeclared  " % name, 0)
                return None
        else:
            entry = self.declare_var(name, py_object_type, pos)
        entry.as_module = scope
        self.add_imported_module(scope)
        return entry
    
    def declare_var(self, name, type, pos, 
            cname = None, visibility = 'private', is_cdef = 0):
        # Add an entry for a global variable. If it is a Python
        # object type, and not declared with cdef, it will live 
        # in the module dictionary, otherwise it will be a C 
        # global variable.
        entry = Scope.declare_var(self, name, type, pos, 
            cname, visibility, is_cdef)
        if not visibility in ('private', 'public', 'extern'):
            error(pos, "Module-level variable cannot be declared %s" % visibility)
        if not is_cdef:
            if type is unspecified_type:
                type = py_object_type
            if not (type.is_pyobject and not type.is_extension_type):
                raise InternalError(
                    "Non-cdef global variable is not a generic Python object")
            entry.is_pyglobal = 1
        else:
            entry.is_cglobal = 1
            if entry.type.is_pyobject:
                entry.init = 0
            self.var_entries.append(entry)
        return entry
    
    def declare_global(self, name, pos):
        entry = self.lookup_here(name)
        if not entry:
            self.declare_var(name, py_object_type, pos)
    
    def use_utility_code(self, new_code):
        if new_code is not None:
            self.utility_code_list.append(new_code)

    def declare_c_class(self, name, pos, defining = 0, implementing = 0,
        module_name = None, base_type = None, objstruct_cname = None,
        typeobj_cname = None, typeptr_cname = None, visibility = 'private', typedef_flag = 0, api = 0,
        buffer_defaults = None):
        # If this is a non-extern typedef class, expose the typedef, but use
        # the non-typedef struct internally to avoid needing forward
        # declarations for anonymous structs. 
        if typedef_flag and visibility != 'extern':
            if visibility != 'public':
                warning(pos, "ctypedef only valid for public and extern classes", 2)
            objtypedef_cname = objstruct_cname
            objstruct_cname = None
            typedef_flag = 0
        else:
            objtypedef_cname = None
        #
        #  Look for previous declaration as a type
        #
        entry = self.lookup_here(name)
        if entry:
            type = entry.type
            if not (entry.is_type and type.is_extension_type):
                entry = None # Will cause redeclaration and produce an error
            else:
                scope = type.scope
                if typedef_flag and (not scope or scope.defined):
                    self.check_previous_typedef_flag(entry, typedef_flag, pos)
                if (scope and scope.defined) or (base_type and type.base_type):
                    if base_type and base_type is not type.base_type:
                        error(pos, "Base type does not match previous declaration")
                if base_type and not type.base_type:
                    type.base_type = base_type
        #
        #  Make a new entry if needed
        #
        if not entry:
            type = PyrexTypes.PyExtensionType(name, typedef_flag, base_type, visibility == 'extern')
            type.pos = pos
            type.buffer_defaults = buffer_defaults
            if objtypedef_cname is not None:
                type.objtypedef_cname = objtypedef_cname
            if visibility == 'extern':
                type.module_name = module_name
            else:
                type.module_name = self.qualified_name
            if typeptr_cname:
                type.typeptr_cname = typeptr_cname
            else:
                type.typeptr_cname = self.mangle(Naming.typeptr_prefix, name)
            entry = self.declare_type(name, type, pos, visibility = visibility,
                defining = 0)
            entry.is_cclass = True
            if objstruct_cname:
                type.objstruct_cname = objstruct_cname
            elif not entry.in_cinclude:
                type.objstruct_cname = self.mangle(Naming.objstruct_prefix, name)
            else:
                error(entry.pos, 
                    "Object name required for 'public' or 'extern' C class")
            self.attach_var_entry_to_c_class(entry)
            self.c_class_entries.append(entry)
        #
        #  Check for re-definition and create scope if needed
        #
        if not type.scope:
            if defining or implementing:
                scope = CClassScope(name = name, outer_scope = self,
                    visibility = visibility)
                if base_type and base_type.scope:
                    scope.declare_inherited_c_attributes(base_type.scope)
                type.set_scope(scope)
                self.type_entries.append(entry)
            else:
                self.check_for_illegal_incomplete_ctypedef(typedef_flag, pos)
        else:
            if defining and type.scope.defined:
                error(pos, "C class '%s' already defined" % name)
            elif implementing and type.scope.implemented:
                error(pos, "C class '%s' already implemented" % name)
        #
        #  Fill in options, checking for compatibility with any previous declaration
        #
        if defining:
            entry.defined_in_pxd = 1
        if implementing:   # So that filenames in runtime exceptions refer to
            entry.pos = pos  # the .pyx file and not the .pxd file
        if visibility != 'private' and entry.visibility != visibility:
            error(pos, "Class '%s' previously declared as '%s'"
                % (name, entry.visibility))
        if api:
            entry.api = 1
        if objstruct_cname:
            if type.objstruct_cname and type.objstruct_cname != objstruct_cname:
                error(pos, "Object struct name differs from previous declaration")
            type.objstruct_cname = objstruct_cname        
        if typeobj_cname:
            if type.typeobj_cname and type.typeobj_cname != typeobj_cname:
                    error(pos, "Type object name differs from previous declaration")
            type.typeobj_cname = typeobj_cname
        #
        # Return new or existing entry    
        #
        return entry
    
    def check_for_illegal_incomplete_ctypedef(self, typedef_flag, pos):
        if typedef_flag and not self.in_cinclude:
            error(pos, "Forward-referenced type must use 'cdef', not 'ctypedef'")
    
    def allocate_vtable_names(self, entry):
        #  If extension type has a vtable, allocate vtable struct and
        #  slot names for it.
        type = entry.type
        if type.base_type and type.base_type.vtabslot_cname:
            #print "...allocating vtabslot_cname because base type has one" ###
            type.vtabslot_cname = "%s.%s" % (
                Naming.obj_base_cname, type.base_type.vtabslot_cname)
        elif type.scope and type.scope.cfunc_entries:
            #print "...allocating vtabslot_cname because there are C methods" ###
            type.vtabslot_cname = Naming.vtabslot_cname
        if type.vtabslot_cname:
            #print "...allocating other vtable related cnames" ###
            type.vtabstruct_cname = self.mangle(Naming.vtabstruct_prefix, entry.name)
            type.vtabptr_cname = self.mangle(Naming.vtabptr_prefix, entry.name)

    def check_c_classes_pxd(self):
        # Performs post-analysis checking and finishing up of extension types
        # being implemented in this module. This is called only for the .pxd.
        #
        # Checks all extension types declared in this scope to
        # make sure that:
        #
        #    * The extension type is fully declared
        #
        # Also allocates a name for the vtable if needed.
        #
        for entry in self.c_class_entries:
            # Check defined
            if not entry.type.scope:
                error(entry.pos, "C class '%s' is declared but not defined" % entry.name)
                
    def check_c_classes(self):
        # Performs post-analysis checking and finishing up of extension types
        # being implemented in this module. This is called only for the main
        # .pyx file scope, not for cimported .pxd scopes.
        #
        # Checks all extension types declared in this scope to
        # make sure that:
        #
        #    * The extension type is implemented
        #    * All required object and type names have been specified or generated
        #    * All non-inherited C methods are implemented
        #
        # Also allocates a name for the vtable if needed.
        #
        debug_check_c_classes = 0
        if debug_check_c_classes:
            print("Scope.check_c_classes: checking scope " + self.qualified_name)
        for entry in self.c_class_entries:
            if debug_check_c_classes:
                print("...entry %s %s" % (entry.name, entry))
                print("......type = ",  entry.type)
                print("......visibility = ", entry.visibility)
            type = entry.type
            name = entry.name
            visibility = entry.visibility
            # Check defined
            if not type.scope:
                error(entry.pos, "C class '%s' is declared but not defined" % name)
            # Generate typeobj_cname
            if visibility != 'extern' and not type.typeobj_cname:
                type.typeobj_cname = self.mangle(Naming.typeobj_prefix, name)
            ## Generate typeptr_cname
            #type.typeptr_cname = self.mangle(Naming.typeptr_prefix, name)
            # Check C methods defined
            if type.scope:
                for method_entry in type.scope.cfunc_entries:
                    if not method_entry.is_inherited and not method_entry.func_cname:
                        error(method_entry.pos, "C method '%s' is declared but not defined" %
                            method_entry.name)
            # Allocate vtable name if necessary
            if type.vtabslot_cname:
                #print "ModuleScope.check_c_classes: allocating vtable cname for", self ###
                type.vtable_cname = self.mangle(Naming.vtable_prefix, entry.name)
                
    def check_c_functions(self):
        # Performs post-analysis checking making sure all 
        # defined c functions are actually implemented.
        for name, entry in self.entries.items():
            if entry.is_cfunction:
                if (entry.defined_in_pxd 
                        and entry.scope is self
                        and entry.visibility != 'extern'
                        and not entry.in_cinclude 
                        and not entry.is_implemented):
                    error(entry.pos, "Non-extern C function '%s' declared but not defined" % name)
    
    def attach_var_entry_to_c_class(self, entry):
        # The name of an extension class has to serve as both a type
        # name and a variable name holding the type object. It is
        # represented in the symbol table by a type entry with a
        # variable entry attached to it. For the variable entry,
        # we use a read-only C global variable whose name is an
        # expression that refers to the type object.
        import Builtin
        var_entry = Entry(name = entry.name,
            type = Builtin.type_type,
            pos = entry.pos,
            cname = "((PyObject*)%s)" % entry.type.typeptr_cname)
        var_entry.is_variable = 1
        var_entry.is_cglobal = 1
        var_entry.is_readonly = 1
        entry.as_variable = var_entry
    
    def infer_types(self):
        from TypeInference import PyObjectTypeInferer
        PyObjectTypeInferer().infer_types(self)
        
class LocalScope(Scope):    

    def __init__(self, name, outer_scope, parent_scope = None):
        if parent_scope is None:
            parent_scope = outer_scope
        Scope.__init__(self, name, outer_scope, parent_scope)
    
    def mangle(self, prefix, name):
        return prefix + name

    def declare_arg(self, name, type, pos):
        # Add an entry for an argument of a function.
        cname = self.mangle(Naming.var_prefix, name)
        entry = self.declare(name, cname, type, pos, 'private')
        entry.is_variable = 1
        if type.is_pyobject:
            entry.init = "0"
        entry.is_arg = 1
        #entry.borrowed = 1 # Not using borrowed arg refs for now
        self.arg_entries.append(entry)
        self.control_flow.set_state((), (name, 'source'), 'arg')
        return entry
    
    def declare_var(self, name, type, pos, 
            cname = None, visibility = 'private', is_cdef = 0):
        # Add an entry for a local variable.
        if visibility in ('public', 'readonly'):
            error(pos, "Local variable cannot be declared %s" % visibility)
        entry = Scope.declare_var(self, name, type, pos, 
            cname, visibility, is_cdef)
        if type.is_pyobject and not Options.init_local_none:
            entry.init = "0"
        entry.init_to_none = (type.is_pyobject or type.is_unspecified) and Options.init_local_none
        entry.is_local = 1
        self.var_entries.append(entry)
        return entry
    
    def declare_global(self, name, pos):
        # Pull entry from global scope into local scope.
        if self.lookup_here(name):
            warning(pos, "'%s' redeclared  ", 0)
        else:
            entry = self.global_scope().lookup_target(name)
            self.entries[name] = entry
        
    def lookup_from_inner(self, name):
        entry = self.lookup_here(name)
        if entry:
            entry.in_closure = 1
            return entry
        else:
            return (self.outer_scope and self.outer_scope.lookup_from_inner(name)) or None
            
    def mangle_closure_cnames(self, scope_var):
        for entry in self.entries.values():
            if entry.in_closure:
                if not hasattr(entry, 'orig_cname'):
                    entry.orig_cname = entry.cname
                entry.cname = scope_var + "->" + entry.cname
                

class GeneratorLocalScope(LocalScope):

    def mangle_closure_cnames(self, scope_var):
#        for entry in self.entries.values() + self.temp_entries:
#            entry.in_closure = 1
        LocalScope.mangle_closure_cnames(self, scope_var)
    
#    def mangle(self, prefix, name):
#        return "%s->%s" % (Naming.scope_obj_cname, name)

class StructOrUnionScope(Scope):
    #  Namespace of a C struct or union.
    
    def __init__(self, name="?"):
        Scope.__init__(self, name, None, None)

    def declare_var(self, name, type, pos, 
            cname = None, visibility = 'private', is_cdef = 0, allow_pyobject = 0):
        # Add an entry for an attribute.
        if not cname:
            cname = name
            if visibility == 'private':
                cname = c_safe_identifier(cname)
        if type.is_cfunction:
            type = PyrexTypes.CPtrType(type)
        entry = self.declare(name, cname, type, pos, visibility)
        entry.is_variable = 1
        self.var_entries.append(entry)
        if type.is_pyobject and not allow_pyobject:
            error(pos,
                "C struct/union member cannot be a Python object")
        if visibility != 'private':
            error(pos,
                "C struct/union member cannot be declared %s" % visibility)
        return entry

    def declare_cfunction(self, name, type, pos, 
                          cname = None, visibility = 'private', defining = 0,
                          api = 0, in_pxd = 0, modifiers = ()):
        return self.declare_var(name, type, pos, cname, visibility)

class ClassScope(Scope):
    #  Abstract base class for namespace of
    #  Python class or extension type.
    #
    #  class_name     string   Pyrex name of the class
    #  scope_prefix   string   Additional prefix for names
    #                          declared in the class
    #  doc    string or None   Doc string

    def __init__(self, name, outer_scope):
        Scope.__init__(self, name, outer_scope, outer_scope)
        self.class_name = name
        self.doc = None

    def add_string_const(self, value, identifier = False):
        return self.outer_scope.add_string_const(value, identifier)

    def lookup(self, name):
        entry = Scope.lookup(self, name)
        if entry:
            return entry
        if name == "classmethod":
            # We don't want to use the builtin classmethod here 'cause it won't do the 
            # right thing in this scope (as the class memebers aren't still functions). 
            # Don't want to add a cfunction to this scope 'cause that would mess with 
            # the type definition, so we just return the right entry. 
            self.use_utility_code(classmethod_utility_code)
            entry = Entry(
                "classmethod", 
                "__Pyx_Method_ClassMethod", 
                PyrexTypes.CFuncType(
                    py_object_type,
                    [PyrexTypes.CFuncTypeArg("", py_object_type, None)], 0, 0))
            entry.is_cfunction = 1
        return entry
    

class PyClassScope(ClassScope):
    #  Namespace of a Python class.
    #
    #  class_obj_cname     string   C variable holding class object

    is_py_class_scope = 1
    
    def declare_var(self, name, type, pos, 
            cname = None, visibility = 'private', is_cdef = 0):
        if type is unspecified_type:
            type = py_object_type
        # Add an entry for a class attribute.
        entry = Scope.declare_var(self, name, type, pos, 
            cname, visibility, is_cdef)
        entry.is_pyglobal = 1
        return entry

    def add_default_value(self, type):
        return self.outer_scope.add_default_value(type)


class CClassScope(ClassScope):
    #  Namespace of an extension type.
    #
    #  parent_type           CClassType
    #  #typeobj_cname        string or None
    #  #objstruct_cname      string
    #  method_table_cname    string
    #  member_table_cname    string
    #  getset_table_cname    string
    #  has_pyobject_attrs    boolean  Any PyObject attributes?
    #  public_attr_entries   boolean  public/readonly attrs
    #  property_entries      [Entry]
    #  defined               boolean  Defined in .pxd file
    #  implemented           boolean  Defined in .pyx file
    #  inherited_var_entries [Entry]  Adapted var entries from base class
    
    is_c_class_scope = 1
    
    def __init__(self, name, outer_scope, visibility):
        ClassScope.__init__(self, name, outer_scope)
        if visibility != 'extern':
            self.method_table_cname = outer_scope.mangle(Naming.methtab_prefix, name)
            self.member_table_cname = outer_scope.mangle(Naming.memtab_prefix, name)
            self.getset_table_cname = outer_scope.mangle(Naming.gstab_prefix, name)
        self.has_pyobject_attrs = 0
        self.public_attr_entries = []
        self.property_entries = []
        self.inherited_var_entries = []
        self.defined = 0
        self.implemented = 0
    
    def needs_gc(self):
        # If the type or any of its base types have Python-valued
        # C attributes, then it needs to participate in GC.
        return self.has_pyobject_attrs or \
            (self.parent_type.base_type and
                self.parent_type.base_type.scope is not None and
                self.parent_type.base_type.scope.needs_gc())

    def declare_var(self, name, type, pos, 
            cname = None, visibility = 'private', is_cdef = 0):
        if is_cdef:
            # Add an entry for an attribute.
            if self.defined:
                error(pos,
                    "C attributes cannot be added in implementation part of"
                    " extension type defined in a pxd")
            if get_special_method_signature(name):
                error(pos, 
                    "The name '%s' is reserved for a special method."
                        % name)
            if not cname:
                cname = name
                if visibility == 'private':
                    cname = c_safe_identifier(cname)
            entry = self.declare(name, cname, type, pos, visibility)
            entry.is_variable = 1
            self.var_entries.append(entry)
            if type.is_pyobject:
                self.has_pyobject_attrs = 1
            if visibility not in ('private', 'public', 'readonly'):
                error(pos,
                    "Attribute of extension type cannot be declared %s" % visibility)
            if visibility in ('public', 'readonly'):
                if type.pymemberdef_typecode:
                    self.public_attr_entries.append(entry)
                    if name == "__weakref__":
                        error(pos, "Special attribute __weakref__ cannot be exposed to Python")
                else:
                    error(pos,
                        "C attribute of type '%s' cannot be accessed from Python" % type)
            if visibility == 'public' and type.is_extension_type:
                error(pos,
                    "Non-generic Python attribute cannot be exposed for writing from Python")
            return entry
        else:
            if type is unspecified_type:
                type = py_object_type
            # Add an entry for a class attribute.
            entry = Scope.declare_var(self, name, type, pos, 
                cname, visibility, is_cdef)
            entry.is_member = 1
            entry.is_pyglobal = 1 # xxx: is_pyglobal changes behaviour in so many places that
                                  # I keep it in for now. is_member should be enough
                                  # later on
            self.namespace_cname = "(PyObject *)%s" % self.parent_type.typeptr_cname
            return entry


    def declare_pyfunction(self, name, pos):
        # Add an entry for a method.
        if name in ('__eq__', '__ne__', '__lt__', '__gt__', '__le__', '__ge__'):
            error(pos, "Special method %s must be implemented via __richcmp__" % name)
        if name == "__new__":
            warning(pos, "__new__ method of extension type will change semantics "
                "in a future version of Pyrex and Cython. Use __cinit__ instead.")
            name = EncodedString("__cinit__")
        entry = self.declare_var(name, py_object_type, pos, visibility='extern')
        special_sig = get_special_method_signature(name)
        if special_sig:
            # Special methods get put in the method table with a particular
            # signature declared in advance.
            entry.signature = special_sig
            entry.is_special = 1
        else:
            entry.signature = pymethod_signature
            entry.is_special = 0

        self.pyfunc_entries.append(entry)
        return entry
    
    def lookup_here(self, name):
        if name == "__new__":
            name = EncodedString("__cinit__")
        return ClassScope.lookup_here(self, name)
    
    def declare_cfunction(self, name, type, pos,
                          cname = None, visibility = 'private',
                          defining = 0, api = 0, in_pxd = 0, modifiers = ()):
        if get_special_method_signature(name):
            error(pos, "Special methods must be declared with 'def', not 'cdef'")
        args = type.args
        if not args:
            error(pos, "C method has no self argument")
        elif not args[0].type.same_as(self.parent_type):
            error(pos, "Self argument (%s) of C method '%s' does not match parent type (%s)" %
                  (args[0].type, name, self.parent_type))
        entry = self.lookup_here(name)
        if entry:
            if not entry.is_cfunction:
                warning(pos, "'%s' redeclared  " % name, 0)
            else:
                if defining and entry.func_cname:
                    error(pos, "'%s' already defined" % name)
                #print "CClassScope.declare_cfunction: checking signature" ###
                if type.same_c_signature_as(entry.type, as_cmethod = 1) and type.nogil == entry.type.nogil:
                    pass
                elif type.compatible_signature_with(entry.type, as_cmethod = 1) and type.nogil == entry.type.nogil:
                    entry = self.add_cfunction(name, type, pos, cname or name, visibility='ignore', modifiers=modifiers)
                    defining = 1
                else:
                    error(pos, "Signature not compatible with previous declaration")
                    error(entry.pos, "Previous declaration is here")
        else:
            if self.defined:
                error(pos,
                    "C method '%s' not previously declared in definition part of"
                    " extension type" % name)
            entry = self.add_cfunction(name, type, pos, cname or name,
                                       visibility, modifiers)
        if defining:
            entry.func_cname = self.mangle(Naming.func_prefix, name)
        return entry
        
    def add_cfunction(self, name, type, pos, cname, visibility, modifiers):
        # Add a cfunction entry without giving it a func_cname.
        prev_entry = self.lookup_here(name)
        entry = ClassScope.add_cfunction(self, name, type, pos, cname,
                                         visibility, modifiers)
        entry.is_cmethod = 1
        entry.prev_entry = prev_entry
        return entry
    
    def declare_property(self, name, doc, pos):
        entry = self.lookup_here(name)
        if entry is None:
            entry = self.declare(name, name, py_object_type, pos, 'private')
        entry.is_property = 1
        entry.doc = doc
        entry.scope = PropertyScope(name, 
            outer_scope = self.global_scope(), parent_scope = self)
        entry.scope.parent_type = self.parent_type
        self.property_entries.append(entry)
        return entry
    
    def declare_inherited_c_attributes(self, base_scope):
        # Declare entries for all the C attributes of an
        # inherited type, with cnames modified appropriately
        # to work with this type.
        def adapt(cname):
            return "%s.%s" % (Naming.obj_base_cname, base_entry.cname)
        for base_entry in \
            base_scope.inherited_var_entries + base_scope.var_entries:
                entry = self.declare(base_entry.name, adapt(base_entry.cname), 
                    base_entry.type, None, 'private')
                entry.is_variable = 1
                self.inherited_var_entries.append(entry)
        for base_entry in base_scope.cfunc_entries:
            entry = self.add_cfunction(base_entry.name, base_entry.type,
                                       base_entry.pos, adapt(base_entry.cname),
                                       base_entry.visibility, base_entry.func_modifiers)
            entry.is_inherited = 1
            
        
class PropertyScope(Scope):
    #  Scope holding the __get__, __set__ and __del__ methods for
    #  a property of an extension type.
    #
    #  parent_type   PyExtensionType   The type to which the property belongs
    
    def declare_pyfunction(self, name, pos):
        # Add an entry for a method.
        signature = get_property_accessor_signature(name)
        if signature:
            entry = self.declare(name, name, py_object_type, pos, 'private')
            entry.is_special = 1
            entry.signature = signature
            return entry
        else:
            error(pos, "Only __get__, __set__ and __del__ methods allowed "
                "in a property declaration")
            return None


# Should this go elsewhere (and then get imported)?
#------------------------------------------------------------------------------------

classmethod_utility_code = Code.UtilityCode(
proto = """
#include "descrobject.h"
static PyObject* __Pyx_Method_ClassMethod(PyObject *method); /*proto*/
""",
impl = """
static PyObject* __Pyx_Method_ClassMethod(PyObject *method) {
    /* It appears that PyMethodDescr_Type is not anywhere exposed in the Python/C API */
    static PyTypeObject *methoddescr_type = NULL;
    if (methoddescr_type == NULL) {
       PyObject *meth = __Pyx_GetAttrString((PyObject*)&PyList_Type, "append");
       if (!meth) return NULL;
       methoddescr_type = Py_TYPE(meth);
       Py_DECREF(meth);
    }
    if (PyObject_TypeCheck(method, methoddescr_type)) { /* cdef classes */
        PyMethodDescrObject *descr = (PyMethodDescrObject *)method;
        #if PY_VERSION_HEX < 0x03020000
        PyTypeObject *d_type = descr->d_type;
        #else
        PyTypeObject *d_type = descr->d_common.d_type;
        #endif
        return PyDescr_NewClassMethod(d_type, descr->d_method);
    }
    else if (PyMethod_Check(method)) { /* python classes */
        return PyClassMethod_New(PyMethod_GET_FUNCTION(method));
    }
    else if (PyCFunction_Check(method)) {
        return PyClassMethod_New(method);
    }
    PyErr_Format(PyExc_TypeError,
                 "Class-level classmethod() can only be called on"
                 "a method_descriptor or instance method.");
    return NULL;
}
""")