| 1 | """
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| 2 | runtime.py: Objects and types needed at runtime.
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| 3 |
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| 4 | asdl/front_end.py and asdl/asdl_.py should not be shipped with the binary.
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| 5 | They are only needed for the gen_python.py compiler.
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| 6 | """
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| 7 | from __future__ import print_function
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| 8 |
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| 9 | #import posix
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| 10 |
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| 11 | import cStringIO
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| 12 | Buffer = cStringIO.StringIO
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| 13 |
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| 14 |
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| 15 | # Type Descriptors
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| 16 | #
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| 17 | # These are more convenient than using the AST directly, since it still has
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| 18 | # string type names?
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| 19 | #
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| 20 | # Although we share Product and Sum.
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| 21 |
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| 22 | class _RuntimeType(object):
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| 23 | """A node hierarchy that exists at runtime."""
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| 24 | pass
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| 25 |
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| 26 |
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| 27 | class StrType(_RuntimeType):
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| 28 | def __repr__(self):
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| 29 | return '<Str>'
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| 30 |
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| 31 |
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| 32 | class IntType(_RuntimeType):
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| 33 | def __repr__(self):
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| 34 | return '<Int>'
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| 35 |
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| 36 |
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| 37 | class BoolType(_RuntimeType):
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| 38 | def __repr__(self):
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| 39 | return '<Bool>'
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| 40 |
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| 41 |
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| 42 | class DictType(_RuntimeType):
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| 43 | def __repr__(self):
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| 44 | return '<Dict>'
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| 45 |
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| 46 |
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| 47 | class ArrayType(_RuntimeType):
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| 48 | def __init__(self, desc):
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| 49 | self.desc = desc
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| 50 |
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| 51 | def __repr__(self):
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| 52 | return '<Array %s>' % self.desc
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| 53 |
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| 54 |
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| 55 | class MaybeType(_RuntimeType):
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| 56 | def __init__(self, desc):
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| 57 | self.desc = desc # another descriptor
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| 58 |
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| 59 | def __repr__(self):
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| 60 | return '<Maybe %s>' % self.desc
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| 61 |
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| 62 |
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| 63 | class UserType(_RuntimeType):
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| 64 | def __init__(self, typ):
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| 65 | assert isinstance(typ, type), typ
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| 66 | self.typ = typ
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| 67 |
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| 68 | def __repr__(self):
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| 69 | return '<UserType %s>' % self.typ
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| 70 |
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| 71 |
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| 72 | class SumType(_RuntimeType):
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| 73 | """Dummy node that doesn't require any reflection.
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| 74 |
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| 75 | obj.ASDL_TYPE points directly to the constructor, which you reflect on.
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| 76 | """
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| 77 | def __init__(self, is_simple):
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| 78 | self.is_simple = is_simple # for type checking
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| 79 | self.cases = [] # list of _RuntimeType for type checking
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| 80 |
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| 81 | def __repr__(self):
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| 82 | # We need an entry for this but we don't use it?
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| 83 | return '<SumType with %d cases at %d>' % (
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| 84 | len(self.cases), id(self))
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| 85 |
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| 86 |
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| 87 | class CompoundType(_RuntimeType):
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| 88 | """A product or Constructor instance. Both have fields."""
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| 89 | def __init__(self, fields):
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| 90 | # List of (name, _RuntimeType) tuples.
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| 91 | # NOTE: This list may be mutated after its set.
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| 92 | self.fields = fields
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| 93 |
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| 94 | def __repr__(self):
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| 95 | return '<CompoundType %s>' % self.fields
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| 96 |
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| 97 | def GetFieldNames(self):
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| 98 | for field_name, _ in self.fields:
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| 99 | yield field_name
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| 100 |
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| 101 | def GetFields(self):
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| 102 | for field_name, descriptor in self.fields:
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| 103 | yield field_name, descriptor
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| 104 |
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| 105 | def LookupFieldType(self, field_name):
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| 106 | """
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| 107 | NOTE: Only used by py_meta.py.
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| 108 | """
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| 109 | for n, descriptor in self.fields:
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| 110 | if n == field_name:
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| 111 | return descriptor
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| 112 | raise TypeError('Invalid field %r' % field_name)
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| 113 |
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| 114 |
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| 115 | BUILTIN_TYPES = {
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| 116 | 'string': StrType(),
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| 117 | 'int': IntType(),
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| 118 | 'bool': BoolType(),
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| 119 | 'dict': DictType(),
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| 120 | }
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| 121 |
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| 122 |
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| 123 |
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| 124 |
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| 125 | class Obj(object):
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| 126 | # NOTE: We're using CAPS for these static fields, since they are constant at
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| 127 | # runtime after metaprogramming.
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| 128 | ASDL_TYPE = None # Used for type checking
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| 129 |
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| 130 |
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| 131 | class SimpleObj(Obj):
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| 132 | """An enum value.
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| 133 |
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| 134 | Other simple objects: int, str, maybe later a float.
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| 135 | """
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| 136 | def __init__(self, enum_id, name):
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| 137 | self.enum_id = enum_id
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| 138 | self.name = name
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| 139 |
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| 140 | # TODO: Why is __hash__ needed? Otherwise native/fastlex_test.py fails.
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| 141 | # util.Enum required it too. I thought that instances would hash by
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| 142 | # identity?
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| 143 | #
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| 144 | # Example:
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| 145 | # class bool_arg_type_e(py_meta.SimpleObj):
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| 146 | # ASDL_TYPE = TYPE_LOOKUP['bool_arg_type']
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| 147 | # bool_arg_type_e.Undefined = bool_arg_type_e(1, 'Undefined')
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| 148 |
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| 149 | def __hash__(self):
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| 150 | # Could it be the integer self.enum_id?
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| 151 | return hash(self.__class__.__name__ + self.name)
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| 152 |
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| 153 | def __repr__(self):
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| 154 | return '<%s %s %s>' % (self.__class__.__name__, self.name, self.enum_id)
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| 155 |
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| 156 |
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| 157 | NUM_TYPE_CHECKS = 0
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| 158 |
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| 159 | class CompoundObj(Obj):
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| 160 | # TODO: Remove tag?
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| 161 | # The tag is always set for constructor types, which are subclasses of sum
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| 162 | # types. Never set for product types.
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| 163 | tag = None
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| 164 |
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| 165 |
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| 166 | # Other possible dynamic checking:
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| 167 | # - CheckUnassigned in the constructor? Fields should be all initialized or
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| 168 | # none.
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| 169 | # - Maybe spids should never be mutated? It can only be appended to?
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| 170 | # - SimpleObj could deny all __setattr__?
|