#!/usr/bin/env python  """ Generate C code from object layouts and other deduced information.  Copyright (C) 2015, 2016, 2017 Paul Boddie <paul@boddie.org.uk>  This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.  You should have received a copy of the GNU General Public License along with this program.  If not, see <http://www.gnu.org/licenses/>. """  from common import CommonOutput, copy from encoders import encode_code, \                      encode_function_pointer, \                      encode_instantiator_pointer, \                      encode_literal_constant, encode_literal_constant_member, \                      encode_literal_constant_size, encode_literal_constant_value, \                      encode_literal_data_initialiser, \                      encode_literal_instantiator, encode_literal_reference, \                      encode_path, encode_pcode, encode_pos, encode_ppos, \                      encode_predefined_reference, encode_size, \                      encode_symbol, encode_tablename, \                      encode_type_attribute, decode_type_attribute, \                      is_type_attribute from os import listdir, mkdir, remove from os.path import exists, isdir, join, split, splitext from referencing import Reference  class Generator(CommonOutput):      "A code generator."      # NOTE: These must be synchronised with the library.      function_type = "__builtins__.core.function"     none_type = "__builtins__.none.NoneType"     string_type = "__builtins__.str.string"     type_type = "__builtins__.core.type"     unicode_type = "__builtins__.unicode.utf8string"      none_value = "__builtins__.none.None"      predefined_constant_members = (         ("__builtins__.boolean", "False"),         ("__builtins__.boolean", "True"),         ("__builtins__.none", "None"),         ("__builtins__.notimplemented", "NotImplemented"),         )      literal_mapping_types = (         "__builtins__.dict.dict",         )      literal_sequence_types = (         "__builtins__.list.list",         "__builtins__.tuple.tuple",         )      literal_instantiator_types = literal_mapping_types + literal_sequence_types      def __init__(self, importer, optimiser, output):          """         Initialise the generator with the given 'importer', 'optimiser' and         'output' directory.         """          self.importer = importer         self.optimiser = optimiser         self.output = output      def to_output(self, debug=False, gc_sections=False):          "Write the generated code."          self.check_output("debug=%r gc_sections=%r" % (debug, gc_sections))         self.write_structures()         self.write_scripts(debug, gc_sections)         self.copy_templates()      def copy_templates(self):          "Copy template files to the generated output directory."          templates = join(split(__file__)[0], "templates")          for filename in listdir(templates):             target = self.output             pathname = join(templates, filename)              # Copy files into the target directory.              if not isdir(pathname):                 copy(pathname, target)              # Copy directories (such as the native code directory).              else:                 target = join(self.output, filename)                  if not exists(target):                     mkdir(target)                  existing = listdir(target)                 needed = listdir(pathname)                  # Determine which files are superfluous by comparing their                 # basenames (without extensions) to those of the needed                 # filenames. This should preserve object files for needed source                 # files, only discarding completely superfluous files from the                 # target directory.                  needed_basenames = set()                 for filename in needed:                     needed_basenames.add(splitext(filename)[0])                  superfluous = []                 for filename in existing:                     if splitext(filename)[0] not in needed_basenames:                         superfluous.append(filename)                  # Copy needed files.                  for filename in needed:                     copy(join(pathname, filename), target)                  # Remove superfluous files.                  for filename in superfluous:                     remove(join(target, filename))      def write_structures(self):          "Write structures used by the program."          f_consts = open(join(self.output, "progconsts.h"), "w")         f_defs = open(join(self.output, "progtypes.c"), "w")         f_decls = open(join(self.output, "progtypes.h"), "w")         f_signatures = open(join(self.output, "main.h"), "w")         f_code = open(join(self.output, "main.c"), "w")          try:             # Output boilerplate.              print >>f_consts, """\ #ifndef __PROGCONSTS_H__ #define __PROGCONSTS_H__  #include "types.h" """             print >>f_decls, """\ #ifndef __PROGTYPES_H__ #define __PROGTYPES_H__  #include "progconsts.h" #include "types.h" """             print >>f_defs, """\ #include "progtypes.h" #include "progops.h" #include "main.h" """             print >>f_signatures, """\ #ifndef __MAIN_H__ #define __MAIN_H__  #include "types.h" """             print >>f_code, """\ #include <string.h> #include <stdio.h> #include "gc.h" #include "types.h" #include "exceptions.h" #include "ops.h" #include "progconsts.h" #include "progtypes.h" #include "main.h" #include "progops.h" """              # Generate table and structure data.              function_instance_attrs = None             objects = self.optimiser.attr_table.items()             objects.sort()              self.callables = {}              for ref, indexes in objects:                 attrnames = self.get_attribute_names(indexes)                  kind = ref.get_kind()                 path = ref.get_origin()                 table_name = encode_tablename(kind, path)                 structure_size = encode_size(kind, path)                  # Generate structures for classes and modules.                  if kind != "<instance>":                     structure = []                     attrs = self.get_static_attributes(kind, path, attrnames)                      # Set a special instantiator on the class.                      if kind == "<class>":                          # Write instantiator declarations based on the                         # applicable initialiser.                          init_ref = attrs["__init__"]                          # Write instantiator definitions.                          self.write_instantiator(f_code, f_signatures, path, init_ref)                          # Record the callable for parameter table generation.                          self.callables[path] = init_ref.get_origin()                          # Define special attributes.                          attrs["__fn__"] = path                         attrs["__args__"] = path                      self.populate_structure(Reference(kind, path), attrs, kind, structure)                      if kind == "<class>":                         self.write_instance_structure(f_decls, path, structure_size)                      self.write_structure(f_decls, f_defs, path, table_name, structure,                         kind == "<class>" and path)                  # Record function instance details for function generation below.                  else:                     attrs = self.get_instance_attributes(path, attrnames)                     if path == self.function_type:                         function_instance_attrs = attrs                          # Record the callable for parameter table generation.                          self.callables[path] = path                  # Write a table for all objects.                  table = []                 self.populate_table(Reference(kind, path), table)                 self.write_table(f_decls, f_defs, table_name, structure_size, table)              # Generate function instances.              functions = self.importer.function_parameters.keys()             functions.sort()             extra_function_instances = []              for path in functions:                  # Instantiators are generated above.                  if self.importer.classes.has_key(path) or not self.importer.get_object(path):                     continue                  # Record the callable for parameter table generation.                  self.callables[path] = path                  # Define the structure details.                  cls = self.function_type                 table_name = encode_tablename("<instance>", cls)                 structure_size = encode_size("<instance>", path)                  # Set a special callable attribute on the instance.                  function_instance_attrs["__fn__"] = path                 function_instance_attrs["__args__"] = path                  structure = self.populate_function(path, function_instance_attrs)                 self.write_structure(f_decls, f_defs, path, table_name, structure)                  # Functions with defaults need to declare instance structures.                  if self.importer.function_defaults.get(path):                     self.write_instance_structure(f_decls, path, structure_size)                     extra_function_instances.append(path)                  # Write function declarations.                 # Signature: __attr <name>(__attr[]);                  print >>f_signatures, "__attr %s(__attr args[]);" % encode_function_pointer(path)              # Generate parameter table size data.              min_parameters = {}             max_parameters = {}             size_parameters = {}              # Consolidate parameter tables for instantiators and functions.              parameter_tables = set()              for path, function_path in self.callables.items():                 argmin, argmax = self.get_argument_limits(function_path)                  # Obtain the parameter table members.                  parameters = self.optimiser.parameters[function_path]                 if not parameters:                     parameters = ()                 else:                     parameters = tuple(parameters)                  # Define each table in terms of the members and the minimum                 # number of arguments.                  parameter_tables.add((argmin, parameters))                 signature = self.get_parameter_signature(argmin, parameters)                  # Record the minimum number of arguments, the maximum number,                 # and the size of the table.                  min_parameters[signature] = argmin                 max_parameters[signature] = argmax                 size_parameters[signature] = len(parameters)              self.write_size_constants(f_consts, "pmin", min_parameters, 0)             self.write_size_constants(f_consts, "pmax", max_parameters, 0)             self.write_size_constants(f_consts, "psize", size_parameters, 0)              # Generate parameter tables for distinct function signatures.              for argmin, parameters in parameter_tables:                 self.make_parameter_table(f_decls, f_defs, argmin, parameters)              # Generate predefined constants.              for path, name in self.predefined_constant_members:                 self.make_predefined_constant(f_decls, f_defs, path, name)              # Generate literal constants.              for constant, n in self.optimiser.constants.items():                 self.make_literal_constant(f_decls, f_defs, n, constant)              # Finish the main source file.              self.write_main_program(f_code, f_signatures)              # Record size information for certain function instances as well as             # for classes, modules and other instances.              size_tables = {}              for kind in ["<class>", "<module>", "<instance>"]:                 size_tables[kind] = {}              # Generate structure size data.              for ref, structure in self.optimiser.structures.items():                 size_tables[ref.get_kind()][ref.get_origin()] = len(structure)              for path in extra_function_instances:                 defaults = self.importer.function_defaults[path]                 size_tables["<instance>"][path] = size_tables["<instance>"][self.function_type] + len(defaults)              size_tables = size_tables.items()             size_tables.sort()              for kind, sizes in size_tables:                 self.write_size_constants(f_consts, kind, sizes, 0)              # Generate parameter codes.              self.write_code_constants(f_consts, self.optimiser.all_paramnames,                                       self.optimiser.arg_locations,                                       "pcode", "ppos", encode_pcode, encode_ppos)              # Generate attribute codes.              self.write_code_constants(f_consts, self.optimiser.all_attrnames,                                       self.optimiser.locations,                                       "code", "pos", encode_code, encode_pos)              # Output more boilerplate.              print >>f_consts, """\  #endif /* __PROGCONSTS_H__ */"""              print >>f_decls, """\  #define __FUNCTION_TYPE %s #define __FUNCTION_INSTANCE_SIZE %s #define __TYPE_CLASS_TYPE %s #define __TYPE_CLASS_POS %s #define __TYPE_CLASS_CODE %s  #endif /* __PROGTYPES_H__ */""" % (     encode_path(self.function_type),     encode_size("<instance>", self.function_type),     encode_path(self.type_type),     encode_pos(encode_type_attribute(self.type_type)),     encode_code(encode_type_attribute(self.type_type)),     )              print >>f_signatures, """\  #endif /* __MAIN_H__ */"""          finally:             f_consts.close()             f_defs.close()             f_decls.close()             f_signatures.close()             f_code.close()      def write_scripts(self, debug, gc_sections):          "Write scripts used to build the program."          f_native = open(join(self.output, "native.mk"), "w")         f_modules = open(join(self.output, "modules.mk"), "w")         f_options = open(join(self.output, "options.mk"), "w")         try:             if debug:                 print >>f_options, "CFLAGS = -g"              if gc_sections:                 print >>f_options, "include gc_sections.mk"              # Identify modules used by the program.              native_modules = [join("native", "common.c")]             modules = []              for name in self.importer.modules.keys():                 parts = name.split(".", 1)                  # Identify source files to be built.                  if parts[0] == "native":                     native_modules.append(join("native", "%s.c" % parts[1]))                 else:                     modules.append(join("src", "%s.c" % name))              print >>f_native, "SRC =", " ".join(native_modules)             print >>f_modules, "SRC +=", " ".join(modules)          finally:             f_native.close()             f_modules.close()             f_options.close()      def make_literal_constant(self, f_decls, f_defs, n, constant):          """         Write literal constant details to 'f_decls' (to declare a structure) and         to 'f_defs' (to define the contents) for the constant with the number         'n' with the given 'constant'.         """          value, value_type, encoding = constant          const_path = encode_literal_constant(n)         structure_name = encode_literal_reference(n)          ref = Reference("<instance>", value_type)         self.make_constant(f_decls, f_defs, ref, const_path, structure_name, value, encoding)      def make_predefined_constant(self, f_decls, f_defs, path, name):          """         Write predefined constant details to 'f_decls' (to declare a structure)         and to 'f_defs' (to define the contents) for the constant located in         'path' with the given 'name'.         """          # Determine the details of the constant.          attr_path = "%s.%s" % (path, name)         structure_name = encode_predefined_reference(attr_path)         ref = self.importer.get_object(attr_path)          self.make_constant(f_decls, f_defs, ref, attr_path, structure_name)      def make_constant(self, f_decls, f_defs, ref, const_path, structure_name, data=None, encoding=None):          """         Write constant details to 'f_decls' (to declare a structure) and to         'f_defs' (to define the contents) for the constant described by 'ref'         having the given 'path' and 'structure_name' (for the constant structure         itself).          The additional 'data' and 'encoding' are used to describe specific         values.         """          # Obtain the attributes.          cls = ref.get_origin()         indexes = self.optimiser.attr_table[ref]         attrnames = self.get_attribute_names(indexes)         attrs = self.get_instance_attributes(cls, attrnames)          # Set the data, if provided.          if data is not None:             attrs["__data__"] = data              # Also set a key for dynamic attribute lookup, if a string.              if attrs.has_key("__key__"):                 if data in self.optimiser.all_attrnames:                     attrs["__key__"] = data                 else:                     attrs["__key__"] = None              # Initialise the size, if a string.              if attrs.has_key("__size__"):                 attrs["__size__"] = len(data)          # Define Unicode constant encoding details.          if cls == self.unicode_type:              # Reference the encoding's own constant value.              if encoding:                 n = self.optimiser.constants[(encoding, self.string_type, None)]                  # Employ a special alias that will be tested specifically in                 # encode_member.                  encoding_ref = Reference("<instance>", self.string_type, "$c%s" % n)              # Use None where no encoding was indicated.              else:                 encoding_ref = Reference("<instance>", self.none_type)              attrs["encoding"] = encoding_ref          # Define the structure details. An object is created for the constant,         # but an attribute is provided, referring to the object, for access to         # the constant in the program.          structure = []         table_name = encode_tablename("<instance>", cls)         self.populate_structure(ref, attrs, ref.get_kind(), structure)         self.write_structure(f_decls, f_defs, structure_name, table_name, structure)          # Define a macro for the constant.          attr_name = encode_path(const_path)         print >>f_decls, "#define %s __ATTRVALUE(&%s)" % (attr_name, structure_name)      def make_parameter_table(self, f_decls, f_defs, argmin, parameters):          """         Write parameter table details to 'f_decls' (to declare a table) and to         'f_defs' (to define the contents) for the given 'argmin' and         'parameters'.         """          # Use a signature for the table name instead of a separate name for each         # function.          signature = self.get_parameter_signature(argmin, parameters)         table_name = encode_tablename("<function>", signature)         min_parameters = encode_size("pmin", signature)         max_parameters = encode_size("pmax", signature)         structure_size = encode_size("psize", signature)          table = []         self.populate_parameter_table(parameters, table)         self.write_parameter_table(f_decls, f_defs, table_name, min_parameters, max_parameters, structure_size, table)      def get_parameter_signature(self, argmin, parameters):          "Return a signature for the given 'argmin' and 'parameters'."          l = [str(argmin)]         for parameter in parameters:             if parameter is None:                 l.append("")             else:                 name, pos = parameter                 l.append("%s_%s" % (name, pos))         return l and "__".join(l) or "__void"      def get_signature_for_callable(self, path):          "Return the signature for the callable with the given 'path'."          function_path = self.callables[path]         argmin, argmax = self.get_argument_limits(function_path)         parameters = self.optimiser.parameters[function_path]         return self.get_parameter_signature(argmin, parameters)      def write_size_constants(self, f_consts, size_prefix, sizes, padding):          """         Write size constants to 'f_consts' for the given 'size_prefix', using         the 'sizes' dictionary to populate the definition, adding the given         'padding' to the basic sizes.         """          print >>f_consts, "enum %s {" % encode_size(size_prefix)         first = True         for path, size in sizes.items():             if not first:                 print >>f_consts, ","             else:                 first = False             f_consts.write("    %s = %d" % (encode_size(size_prefix, path), size + padding))         print >>f_consts, "\n    };"      def write_code_constants(self, f_consts, attrnames, locations, code_prefix,                              pos_prefix, code_encoder, pos_encoder):          """         Write code constants to 'f_consts' for the given 'attrnames' and         attribute 'locations'.         """          print >>f_consts, "enum %s {" % encode_symbol(code_prefix)         first = True         for i, attrname in enumerate(attrnames):             if not first:                 print >>f_consts, ","             else:                 first = False             f_consts.write("    %s = %d" % (code_encoder(attrname), i))         print >>f_consts, "\n    };"          print >>f_consts, "enum %s {" % encode_symbol(pos_prefix)         first = True         for i, attrnames in enumerate(locations):             for attrname in attrnames:                 if not first:                     print >>f_consts, ","                 else:                     first = False                 f_consts.write("    %s = %d" % (pos_encoder(attrname), i))         print >>f_consts, "\n    };"      def write_table(self, f_decls, f_defs, table_name, structure_size, table):          """         Write the declarations to 'f_decls' and definitions to 'f_defs' for         the object having the given 'table_name' and the given 'structure_size',         with 'table' details used to populate the definition.         """          print >>f_decls, "extern const __table %s;\n" % table_name          # Write the corresponding definition.          print >>f_defs, """\ const __table %s = {     %s,     {         %s     } }; """ % (table_name, structure_size,        ",\n        ".join(table))      def write_parameter_table(self, f_decls, f_defs, table_name, min_parameters,                               max_parameters, structure_size, table):          """         Write the declarations to 'f_decls' and definitions to 'f_defs' for         the object having the given 'table_name' and the given 'min_parameters',         'max_parameters' and 'structure_size', with 'table' details used to         populate the definition.         """          members = []         for t in table:             members.append("{.code=%s, .pos=%s}" % t)          print >>f_decls, "extern const __ptable %s;\n" % table_name          # Write the corresponding definition.          print >>f_defs, """\ const __ptable %s = {     .min=%s,     .max=%s,     .size=%s,     {         %s     } }; """ % (table_name, min_parameters, max_parameters, structure_size,        ",\n        ".join(members))      def write_instance_structure(self, f_decls, path, structure_size):          """         Write a declaration to 'f_decls' for the object having the given 'path'         and the given 'structure_size'.         """          # Write an instance-specific type definition for instances of classes.         # See: templates/types.h          print >>f_decls, """\ typedef struct {     const __table * table;     __pos pos;     __attr attrs[%s]; } %s; """ % (structure_size, encode_symbol("obj", path))      def write_structure(self, f_decls, f_defs, structure_name, table_name, structure, path=None):          """         Write the declarations to 'f_decls' and definitions to 'f_defs' for         the object having the given 'structure_name', the given 'table_name',         and the given 'structure' details used to populate the definition.         """          if f_decls:             print >>f_decls, "extern __obj %s;\n" % encode_path(structure_name)          is_class = path and self.importer.get_object(path).has_kind("<class>")         pos = is_class and encode_pos(encode_type_attribute(path)) or "0"          print >>f_defs, """\ __obj %s = {     &%s,     %s,     {         %s     }}; """ % (             encode_path(structure_name), table_name, pos,             ",\n        ".join(structure))      def get_argument_limits(self, path):          """         Return the argument minimum and maximum for the callable at 'path',         adding an argument position for a universal context.         """          parameters = self.importer.function_parameters[path]         defaults = self.importer.function_defaults.get(path)         num_parameters = len(parameters) + 1         return num_parameters - (defaults and len(defaults) or 0), num_parameters      def get_attribute_names(self, indexes):          """         Given a list of attribute table 'indexes', return a list of attribute         names.         """          all_attrnames = self.optimiser.all_attrnames         attrnames = []         for i in indexes:             if i is None:                 attrnames.append(None)             else:                 attrnames.append(all_attrnames[i])         return attrnames      def get_static_attributes(self, kind, name, attrnames):          """         Return a mapping of attribute names to paths for attributes belonging         to objects of the given 'kind' (being "<class>" or "<module>") with         the given 'name' and supporting the given 'attrnames'.         """          attrs = {}          for attrname in attrnames:             if attrname is None:                 continue             if kind == "<class>":                 path = self.importer.all_class_attrs[name][attrname]             elif kind == "<module>":                 path = "%s.%s" % (name, attrname)             else:                 continue              # The module may be hidden.              attr = self.importer.get_object(path)             if not attr:                 module = self.importer.hidden.get(path)                 if module:                     attr = Reference(module.name, "<module>")             attrs[attrname] = attr          return attrs      def get_instance_attributes(self, name, attrnames):          """         Return a mapping of attribute names to references for attributes         belonging to instances of the class with the given 'name', where the         given 'attrnames' are supported.         """          consts = self.importer.all_instance_attr_constants[name]         attrs = {}         for attrname in attrnames:             if attrname is None:                 continue             const = consts.get(attrname)             attrs[attrname] = const or Reference("<var>", "%s.%s" % (name, attrname))         return attrs      def populate_table(self, path, table):          """         Traverse the attributes in the determined order for the structure having         the given 'path', adding entries to the attribute 'table'.         """          for attrname in self.optimiser.structures[path]:              # Handle gaps in the structure.              if attrname is None:                 table.append("0")             else:                 table.append(encode_code(attrname))      def populate_parameter_table(self, parameters, table):          """         Traverse the 'parameters' in the determined order, adding entries to the         attribute 'table'.         """          for value in parameters:              # Handle gaps in the structure.              if value is None:                 table.append(("0", "0"))             else:                 name, pos = value                 table.append((encode_symbol("pcode", name), pos))      def populate_function(self, path, function_instance_attrs):          """         Populate a structure for the function with the given 'path'. The given         'attrs' provide the instance attributes.         """          structure = []         self.populate_structure(Reference("<function>", path), function_instance_attrs, "<instance>", structure)          # Append default members.          self.append_defaults(path, structure)         return structure      def populate_structure(self, ref, attrs, kind, structure):          """         Traverse the attributes in the determined order for the structure having         the given 'ref' whose members are provided by the 'attrs' mapping, in a         structure of the given 'kind', adding entries to the object 'structure'.         """          # Populate function instance structures for functions.          if ref.has_kind("<function>"):             origin = self.function_type             structure_ref = Reference("<instance>", self.function_type)          # Otherwise, just populate the appropriate structures.          else:             origin = ref.get_origin()             structure_ref = ref          for attrname in self.optimiser.structures[structure_ref]:              # Handle gaps in the structure.              if attrname is None:                 structure.append("__NULL")              # Handle non-constant and constant members.              else:                 attr = attrs[attrname]                  # Special function pointer member.                  if attrname == "__fn__":                      # Classes offer instantiators which can be called without a                     # context.                      if kind == "<class>":                         attr = encode_instantiator_pointer(attr)                     else:                         attr = encode_function_pointer(attr)                      structure.append("{.fn=%s}" % attr)                     continue                  # Special argument specification member.                  elif attrname == "__args__":                     signature = self.get_signature_for_callable(ref.get_origin())                     ptable = encode_tablename("<function>", signature)                      structure.append("{.ptable=&%s}" % ptable)                     continue                  # Special internal data member.                  elif attrname == "__data__":                     structure.append("{.%s=%s}" % (                                      encode_literal_constant_member(attr),                                      encode_literal_constant_value(attr)))                     continue                  # Special internal size member.                  elif attrname == "__size__":                     structure.append("{.intvalue=%d}" % attr)                     continue                  # Special internal key member.                  elif attrname == "__key__":                     structure.append("{.code=%s, .pos=%s}" % (attr and encode_code(attr) or "0",                                                               attr and encode_pos(attr) or "0"))                     continue                  # Special cases.                  elif attrname in ("__file__", "__name__"):                     path = ref.get_origin()                     value_type = self.string_type                      # Provide constant values. These must match the values                     # originally recorded during inspection.                      if attrname == "__file__":                         module = self.importer.get_module(path)                         value = module.filename                      # Function and class names are leafnames.                      elif attrname == "__name__" and not ref.has_kind("<module>"):                         value = path.rsplit(".", 1)[-1]                      # All other names just use the object path information.                      else:                         value = path                      encoding = None                      local_number = self.importer.all_constants[path][(value, value_type, encoding)]                     constant_name = "$c%d" % local_number                     attr_path = "%s.%s" % (path, constant_name)                     constant_number = self.optimiser.constant_numbers[attr_path]                     constant_value = "__const%s" % constant_number                     structure.append("%s /* %s */" % (constant_value, attrname))                     continue                  elif attrname == "__parent__":                     path = ref.get_origin()                      # Parents of classes and functions are derived from their                     # object paths.                      value = path.rsplit(".", 1)[0]                     structure.append("{.value=&%s}" % encode_path(value))                     continue                  # Special context member.                 # Set the context depending on the kind of attribute.                 # For methods:          <parent>                 # For other attributes: __NULL                  elif attrname == "__context__":                     path = ref.get_origin()                      # Contexts of methods are derived from their object paths.                      context = "0"                      if ref.get_kind() == "<function>":                         parent = path.rsplit(".", 1)[0]                         if self.importer.classes.has_key(parent):                             context = "&%s" % encode_path(parent)                      structure.append("{.value=%s}" % context)                     continue                  # Special class relationship attributes.                  elif is_type_attribute(attrname):                     structure.append("{.value=&%s}" % encode_path(decode_type_attribute(attrname)))                     continue                  # All other kinds of members.                  structure.append(self.encode_member(origin, attrname, attr, kind))      def encode_member(self, path, name, ref, structure_type):          """         Encode within the structure provided by 'path', the member whose 'name'         provides 'ref', within the given 'structure_type'.         """          kind = ref.get_kind()         origin = ref.get_origin()          # References to constant literals.          if kind == "<instance>" and ref.is_constant_alias():             alias = ref.get_name()              # Use the alias directly if appropriate.              if alias.startswith("$c"):                 constant_value = encode_literal_constant(alias[2:])                 return "%s /* %s */" % (constant_value, name)              # Obtain a constant value directly assigned to the attribute.              if self.optimiser.constant_numbers.has_key(alias):                 constant_number = self.optimiser.constant_numbers[alias]                 constant_value = encode_literal_constant(constant_number)                 return "%s /* %s */" % (constant_value, name)          # Usage of predefined constants, currently only None supported.          if kind == "<instance>" and origin == self.none_type:             attr_path = encode_predefined_reference(self.none_value)             return "{.value=&%s} /* %s */" % (attr_path, name)          # Predefined constant members.          if (path, name) in self.predefined_constant_members:             attr_path = encode_predefined_reference("%s.%s" % (path, name))             return "{.value=&%s} /* %s */" % (attr_path, name)          # General undetermined members.          if kind in ("<var>", "<instance>"):             attr_path = encode_predefined_reference(self.none_value)             return "{.value=&%s} /* %s */" % (attr_path, name)          else:             return "{.value=&%s}" % encode_path(origin)      def append_defaults(self, path, structure):          """         For the given 'path', append default parameter members to the given         'structure'.         """          for name, default in self.importer.function_defaults.get(path):             structure.append(self.encode_member(path, name, default, "<instance>"))      def write_instantiator(self, f_code, f_signatures, path, init_ref):          """         Write an instantiator to 'f_code', with a signature to 'f_signatures',         for instances of the class with the given 'path', with 'init_ref' as the         initialiser function reference.          NOTE: This also needs to initialise any __fn__ and __args__ members         NOTE: where __call__ is provided by the class.         """          parameters = self.importer.function_parameters[init_ref.get_origin()]          print >>f_code, """\ __attr %s(__attr __args[]) {     /* Allocate the structure. */     __args[0] = __NEWINSTANCE(%s);      /* Call the initialiser. */     %s(__args);      /* Return the allocated object details. */     return __args[0]; } """ % (     encode_instantiator_pointer(path),     encode_path(path),     encode_function_pointer(init_ref.get_origin())     )          print >>f_signatures, "#define __HAVE_%s" % encode_path(path)         print >>f_signatures, "__attr %s(__attr[]);" % encode_instantiator_pointer(path)          # Write additional literal instantiators. These do not call the         # initialisers but instead populate the structures directly.          if path in self.literal_instantiator_types:             if path in self.literal_mapping_types:                 style = "mapping"             else:                 style = "sequence"              print >>f_code, """\ __attr %s(__attr __args[], __pos number) {     /* Allocate the structure. */     __args[0] = __NEWINSTANCE(%s);      /* Allocate a structure for the data and set it on the __data__ attribute. */     %s(__args, number);      /* Return the allocated object details. */     return __args[0]; } """ % (     encode_literal_instantiator(path),     encode_path(path),     encode_literal_data_initialiser(style)     )              print >>f_signatures, "__attr %s(__attr[], __pos);" % encode_literal_instantiator(path)      def write_main_program(self, f_code, f_signatures):          """         Write the main program to 'f_code', invoking the program's modules. Also         write declarations for module main functions to 'f_signatures'.         """          print >>f_code, """\ int main(int argc, char *argv[]) {     __exc __tmp_exc;      GC_INIT();      __Try     {"""          for name in self.importer.order_modules():             function_name = "__main_%s" % encode_path(name)             print >>f_signatures, "void %s();" % function_name              # Omit the native modules.              parts = name.split(".")              if parts[0] != "native":                 print >>f_code, """\         %s();""" % function_name          print >>f_code, """\     }     __Catch(__tmp_exc)     {         if (__ISINSTANCE(__tmp_exc.arg, __ATTRVALUE(&__builtins___exception_system_SystemExit)))             return __load_via_object(                 __load_via_object(__tmp_exc.arg.value, __data__).value,                 value).intvalue;          fprintf(stderr, "Program terminated due to exception: %%s.\\n",                 __load_via_object(                     %s(__ARGS(__NULL, __tmp_exc.arg)).value,                     __data__).strvalue);         return 1;     }      return 0; } """ % encode_function_pointer("__builtins__.str.str")  # vim: tabstop=4 expandtab shiftwidth=4