third_party/cython/src/Cython/Compiler/Interpreter.py

   1 """
   2 This module deals with interpreting the parse tree as Python
   3 would have done, in the compiler.
   4
   5 For now this only covers parse tree to value conversion of
   6 compile-time values.
   7 """
   8
   9 from Nodes import *
  10 from ExprNodes import *
  11 from Errors import CompileError
  12
  13
  14 class EmptyScope(object):
  15     def lookup(self, name):
  16         return None
  17
  18 empty_scope = EmptyScope()
  19
  20 def interpret_compiletime_options(optlist, optdict, type_env=None, type_args=()):
  21     """
  22     Tries to interpret a list of compile time option nodes.
  23     The result will be a tuple (optlist, optdict) but where
  24     all expression nodes have been interpreted. The result is
  25     in the form of tuples (value, pos).
  26
  27     optlist is a list of nodes, while optdict is a DictNode (the
  28     result optdict is a dict)
  29
  30     If type_env is set, all type nodes will be analysed and the resulting
  31     type set. Otherwise only interpretateable ExprNodes
  32     are allowed, other nodes raises errors.
  33
  34     A CompileError will be raised if there are problems.
  35     """
  36
  37     def interpret(node, ix):
  38         if ix in type_args:
  39             if type_env:
  40                 type = node.analyse_as_type(type_env)
  41                 if not type:
  42                     raise CompileError(node.pos, "Invalid type.")
  43                 return (type, node.pos)
  44             else:
  45                 raise CompileError(node.pos, "Type not allowed here.")
  46         else:
  47             if (sys.version_info[0] >=3 and
  48                 isinstance(node, StringNode) and
  49                 node.unicode_value is not None):
  50                 return (node.unicode_value, node.pos)
  51             return (node.compile_time_value(empty_scope), node.pos)
  52
  53     if optlist:
  54         optlist = [interpret(x, ix) for ix, x in enumerate(optlist)]
  55     if optdict:
  56         assert isinstance(optdict, DictNode)
  57         new_optdict = {}
  58         for item in optdict.key_value_pairs:
  59             new_key, dummy = interpret(item.key, None)
  60             new_optdict[new_key] = interpret(item.value, item.key.value)
  61         optdict = new_optdict
  62     return (optlist, new_optdict)