| 1 | """
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| 2 | runtime.py
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| 3 | """
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| 4 | from __future__ import print_function
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| 5 | 
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| 6 | try:
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| 7 |     import cStringIO
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| 8 | except ImportError:
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| 9 |     # Python 3 doesn't have cStringIO.  Our yaks/ demo currently uses
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| 10 |     # mycpp/mylib.py with Python 3.
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| 11 |     cStringIO = None
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| 12 |     import io
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| 13 | 
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| 14 | import sys
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| 15 | 
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| 16 | from pylib import collections_
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| 17 | try:
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| 18 |     import posix_ as posix
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| 19 | except ImportError:
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| 20 |     # Hack for tangled dependencies.
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| 21 |     import os
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| 22 |     posix = os
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| 23 | 
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| 24 | from typing import (Tuple, List, Dict, Optional, Iterator, Any, TypeVar,
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| 25 |                     Generic, cast, TYPE_CHECKING)
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| 26 | 
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| 27 | # For conditional translation
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| 28 | CPP = False
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| 29 | PYTHON = True
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| 30 | 
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| 31 | # Use POSIX name directly
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| 32 | STDIN_FILENO = 0
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| 33 | 
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| 34 | 
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| 35 | def MaybeCollect():
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| 36 |     # type: () -> None
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| 37 |     pass
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| 38 | 
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| 39 | 
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| 40 | def NewDict():
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| 41 |     # type: () -> Dict[str, Any]
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| 42 |     """Make dictionaries ordered in Python, e.g. for JSON.
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| 43 |   
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| 44 |     In C++, our Dict implementation should be ordered.
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| 45 |     """
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| 46 |     return collections_.OrderedDict()
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| 47 | 
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| 48 | 
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| 49 | def log(msg, *args):
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| 50 |     # type: (str, *Any) -> None
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| 51 |     """Print debug output to stderr."""
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| 52 |     if args:
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| 53 |         msg = msg % args
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| 54 |     print(msg, file=sys.stderr)
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| 55 | 
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| 56 | 
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| 57 | def print_stderr(s):
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| 58 |     # type: (str) -> None
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| 59 |     """Print a message to stderr for the user.
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| 60 | 
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| 61 |     This should be used sparingly, since it doesn't have location info, like
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| 62 |     ui.ErrorFormatter does.  We use it to print fatal I/O errors that were only
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| 63 |     caught at the top level.
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| 64 |     """
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| 65 |     print(s, file=sys.stderr)
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| 66 | 
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| 67 | 
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| 68 | #
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| 69 | # Byte Operations avoid excessive allocations with string algorithms
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| 70 | #
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| 71 | 
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| 72 | 
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| 73 | def ByteAt(s, i):
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| 74 |     # type: (str, int) -> int
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| 75 |     """i must be in bounds."""
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| 76 | 
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| 77 |     # This simplifies the C++ implementation
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| 78 |     assert 0 <= i, 'No negative indices'
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| 79 |     assert i < len(s), 'No negative indices'
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| 80 | 
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| 81 |     return ord(s[i])
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| 82 | 
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| 83 | 
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| 84 | def ByteEquals(byte, ch):
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| 85 |     # type: (int,  str) -> bool
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| 86 |     assert len(ch) == 1, ch
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| 87 |     assert 0 <= byte < 256, byte
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| 88 | 
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| 89 |     return byte == ord(ch)
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| 90 | 
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| 91 | 
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| 92 | def ByteInSet(byte, byte_set):
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| 93 |     # type: (int, str) -> bool
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| 94 |     assert 0 <= byte < 256, byte
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| 95 | 
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| 96 |     return chr(byte) in byte_set
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| 97 | 
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| 98 | 
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| 99 | def JoinBytes(byte_list):
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| 100 |     # type: (List[int]) -> str
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| 101 | 
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| 102 |     return ''.join(chr(b) for b in byte_list)
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| 103 | 
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| 104 | 
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| 105 | class File:
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| 106 |     """
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| 107 |     TODO: This should define a read/write interface, and then LineReader() and
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| 108 |     Writer() can possibly inherit it, with runtime assertions
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| 109 | 
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| 110 |     Then we allow downcasting from File -> LineReader, like we currently do in
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| 111 |     C++ in gc_mylib.h.
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| 112 | 
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| 113 |     Inheritance can't express the structural Reader/Writer pattern of Go, which
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| 114 |     would be better.  I suppose we could use File* everywhere, but having
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| 115 |     fine-grained types is nicer.  And there will be very few casts.
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| 116 |     """
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| 117 |     pass
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| 118 | 
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| 119 | 
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| 120 | class LineReader:
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| 121 | 
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| 122 |     def readline(self):
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| 123 |         # type: () -> str
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| 124 |         raise NotImplementedError()
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| 125 | 
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| 126 |     def close(self):
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| 127 |         # type: () -> None
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| 128 |         raise NotImplementedError()
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| 129 | 
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| 130 |     def isatty(self):
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| 131 |         # type: () -> bool
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| 132 |         raise NotImplementedError()
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| 133 | 
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| 134 | 
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| 135 | if TYPE_CHECKING:
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| 136 | 
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| 137 |     class BufLineReader(LineReader):
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| 138 | 
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| 139 |         def __init__(self, s):
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| 140 |             # type: (str) -> None
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| 141 |             raise NotImplementedError()
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| 142 | 
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| 143 |     def open(path):
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| 144 |         # type: (str) -> LineReader
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| 145 | 
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| 146 |         # TODO: should probably return mylib.File
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| 147 |         # mylib.open() is currently only used in yaks/yaks_main and
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| 148 |         # bin.osh_parse
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| 149 |         raise NotImplementedError()
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| 150 | 
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| 151 | else:
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| 152 |     # Actual runtime
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| 153 |     if cStringIO:
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| 154 |         BufLineReader = cStringIO.StringIO
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| 155 |     else:  # Python 3
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| 156 |         BufLineReader = io.StringIO
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| 157 | 
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| 158 |     open = open
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| 159 | 
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| 160 | 
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| 161 | class Writer:
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| 162 | 
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| 163 |     def write(self, s):
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| 164 |         # type: (str) -> None
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| 165 |         raise NotImplementedError()
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| 166 | 
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| 167 |     def flush(self):
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| 168 |         # type: () -> None
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| 169 |         raise NotImplementedError()
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| 170 | 
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| 171 |     def isatty(self):
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| 172 |         # type: () -> bool
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| 173 |         raise NotImplementedError()
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| 174 | 
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| 175 |     def close(self):
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| 176 |         # type: () -> None
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| 177 |         raise NotImplementedError()
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| 178 | 
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| 179 | 
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| 180 | class BufWriter(Writer):
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| 181 |     """Mimic StringIO API, but add clear() so we can reuse objects.
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| 182 | 
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| 183 |     We can also add accelerators for directly writing numbers, to avoid
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| 184 |     allocations when encoding JSON.
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| 185 |     """
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| 186 | 
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| 187 |     def __init__(self):
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| 188 |         # type: () -> None
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| 189 |         self.parts = []
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| 190 | 
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| 191 |     def write(self, s):
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| 192 |         # type: (str) -> None
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| 193 |         self.parts.append(s)
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| 194 | 
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| 195 |     def write_spaces(self, n):
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| 196 |         # type: (int) -> None
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| 197 |         """For JSON indenting.  Avoid intermediate allocations in C++."""
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| 198 |         self.parts.append(' ' * n)
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| 199 | 
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| 200 |     def getvalue(self):
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| 201 |         # type: () -> str
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| 202 |         return ''.join(self.parts)
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| 203 | 
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| 204 |     def clear(self):
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| 205 |         # type: () -> None
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| 206 |         del self.parts[:]
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| 207 | 
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| 208 |     def close(self):
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| 209 |         # type: () -> None
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| 210 | 
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| 211 |         # No-op for now - we could invalidate write()?
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| 212 | 
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| 213 |         pass
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| 214 | 
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| 215 | 
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| 216 | def Stdout():
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| 217 |     # type: () -> Writer
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| 218 |     return sys.stdout
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| 219 | 
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| 220 | 
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| 221 | def Stderr():
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| 222 |     # type: () -> Writer
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| 223 |     return sys.stderr
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| 224 | 
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| 225 | 
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| 226 | def Stdin():
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| 227 |     # type: () -> LineReader
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| 228 |     return sys.stdin
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| 229 | 
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| 230 | 
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| 231 | class switch(object):
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| 232 |     """Translates to C switch on int.
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| 233 | 
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| 234 |     with tagswitch(i) as case:
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| 235 |         if case(42, 43):
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| 236 |            print('hi')
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| 237 |         elif case(99):
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| 238 |            print('two')
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| 239 |        else:
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| 240 |            print('neither')
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| 241 |     """
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| 242 | 
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| 243 |     def __init__(self, value):
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| 244 |         # type: (int) -> None
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| 245 |         self.value = value
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| 246 | 
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| 247 |     def __enter__(self):
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| 248 |         # type: () -> switch
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| 249 |         return self
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| 250 | 
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| 251 |     def __exit__(self, type, value, traceback):
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| 252 |         # type: (Any, Any, Any) -> bool
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| 253 |         return False  # Allows a traceback to occur
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| 254 | 
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| 255 |     def __call__(self, *cases):
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| 256 |         # type: (*Any) -> bool
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| 257 |         return self.value in cases
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| 258 | 
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| 259 | 
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| 260 | class str_switch(object):
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| 261 |     """Translates to fast dispatch on string length, then memcmp()."""
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| 262 | 
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| 263 |     def __init__(self, value):
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| 264 |         # type: (str) -> None
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| 265 |         self.value = value
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| 266 | 
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| 267 |     def __enter__(self):
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| 268 |         # type: () -> switch
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| 269 |         return self
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| 270 | 
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| 271 |     def __exit__(self, type, value, traceback):
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| 272 |         # type: (Any, Any, Any) -> bool
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| 273 |         return False  # Allows a traceback to occur
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| 274 | 
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| 275 |     def __call__(self, *cases):
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| 276 |         # type: (*Any) -> bool
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| 277 |         return self.value in cases
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| 278 | 
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| 279 | 
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| 280 | class tagswitch(object):
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| 281 |     """A ContextManager that translates to switch statement over ASDL types."""
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| 282 | 
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| 283 |     def __init__(self, node):
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| 284 |         # type: (Any) -> None
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| 285 |         self.tag = node.tag()
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| 286 | 
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| 287 |     def __enter__(self):
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| 288 |         # type: () -> tagswitch
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| 289 |         return self
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| 290 | 
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| 291 |     def __exit__(self, type, value, traceback):
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| 292 |         # type: (Any, Any, Any) -> bool
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| 293 |         return False  # Allows a traceback to occur
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| 294 | 
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| 295 |     def __call__(self, *cases):
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| 296 |         # type: (*Any) -> bool
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| 297 |         return self.tag in cases
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| 298 | 
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| 299 | 
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| 300 | if TYPE_CHECKING:
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| 301 |     # Doesn't work
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| 302 |     T = TypeVar('T')
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| 303 | 
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| 304 |     class StackArray(Generic[T]):
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| 305 | 
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| 306 |         def __init__(self):
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| 307 |             self.items = []  # type: List[T]
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| 308 | 
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| 309 |         def append(self, item):
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| 310 |             # type: (T) -> None
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| 311 |             self.items.append(item)
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| 312 | 
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| 313 |         def pop(self):
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| 314 |             # type: () -> T
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| 315 |             return self.items.pop()
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| 316 | 
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| 317 |     # Doesn't work, this is only for primitive types
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| 318 |     #StackArray = NewType('StackArray', list)
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| 319 | 
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| 320 | 
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| 321 | def MakeStackArray(item_type):
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| 322 |     # type: (TypeVar) -> StackArray[item_type]
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| 323 |     """
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| 324 |     Convenience "constructor" used like this:
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| 325 | 
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| 326 |         myarray = MakeStackArray(int)
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| 327 | 
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| 328 |     The idiom could also be
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| 329 | 
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| 330 |         myarray = cast('StackArray[int]', [])
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| 331 | 
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| 332 |     But that's uglier.
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| 333 |     """
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| 334 |     return cast('StackArray[item_type]', [])
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| 335 | 
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| 336 | 
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| 337 | if TYPE_CHECKING:
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| 338 |     K = TypeVar('K')
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| 339 |     V = TypeVar('V')
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| 340 | 
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| 341 | 
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| 342 | def iteritems(d):
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| 343 |     # type: (Dict[K, V]) -> Iterator[Tuple[K, V]]
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| 344 |     """Make translation a bit easier."""
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| 345 |     return d.iteritems()
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| 346 | 
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| 347 | 
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| 348 | def split_once(s, delim):
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| 349 |     # type: (str, str) -> Tuple[str, Optional[str]]
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| 350 |     """Easier to call than split(s, 1) because of tuple unpacking."""
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| 351 | 
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| 352 |     parts = s.split(delim, 1)
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| 353 |     if len(parts) == 1:
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| 354 |         no_str = None  # type: Optional[str]
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| 355 |         return s, no_str
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| 356 |     else:
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| 357 |         return parts[0], parts[1]
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| 358 | 
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| 359 | 
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| 360 | def hex_lower(i):
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| 361 |     # type: (int) -> str
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| 362 |     return '%x' % i
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| 363 | 
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| 364 | 
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| 365 | def hex_upper(i):
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| 366 |     # type: (int) -> str
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| 367 |     return '%X' % i
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| 368 | 
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| 369 | 
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| 370 | def octal(i):
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| 371 |     # type: (int) -> str
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| 372 |     return '%o' % i
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| 373 | 
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| 374 | 
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| 375 | def dict_erase(d, key):
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| 376 |     # type: (Dict[Any, Any], Any) -> None
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| 377 |     """
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| 378 |     Ensure that a key isn't in the Dict d.  This makes C++ translation easier.
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| 379 |     """
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| 380 |     try:
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| 381 |         del d[key]
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| 382 |     except KeyError:
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| 383 |         pass
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| 384 | 
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| 385 | 
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| 386 | def str_cmp(s1, s2):
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| 387 |     # type: (str, str) -> int
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| 388 |     if s1 == s2:
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| 389 |         return 0
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| 390 |     if s1 < s2:
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| 391 |         return -1
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| 392 |     else:
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| 393 |         return 1
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| 394 | 
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| 395 | 
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| 396 | class UniqueObjects(object):
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| 397 |     """A set of objects identified by their address in memory
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| 398 | 
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| 399 |     Python's id(obj) returns the address of any object.  But we don't simply
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| 400 |     implement it, because it requires a uint64_t on 64-bit systems, while mycpp
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| 401 |     only supports 'int'.
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| 402 | 
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| 403 |     So we have a whole class.
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| 404 | 
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| 405 |     Should be used for:
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| 406 | 
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| 407 |     - Cycle detection when pretty printing, as Python's repr() does
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| 408 |       - See CPython's Objects/object.c PyObject_Repr()
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| 409 |       /* These methods are used to control infinite recursion in repr, str, print,
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| 410 |           etc.  Container objects that may recursively contain themselves,
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| 411 |           e.g. builtin dictionaries and lists, should use Py_ReprEnter() and
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| 412 |           Py_ReprLeave() to avoid infinite recursion.
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| 413 |           */
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| 414 |       - e.g. dictobject.c dict_repr() calls Py_ReprEnter() to print {...}
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| 415 |       - In Python 2.7 a GLOBAL VAR is used
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| 416 | 
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| 417 |       - It also checks for STACK OVERFLOW
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| 418 | 
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| 419 |     - Packle serialization
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| 420 |     """
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| 421 | 
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| 422 |     def __init__(self):
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| 423 |         # 64-bit id() -> small integer ID
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| 424 |         self.addresses = {}  # type: Dict[int, int]
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| 425 | 
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| 426 |     def Contains(self, obj):
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| 427 |         # type: (Any) -> bool
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| 428 |         """ Convenience? """
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| 429 |         return self.Get(obj) != -1
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| 430 | 
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| 431 |     def MaybeAdd(self, obj):
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| 432 |         # type: (Any) -> None
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| 433 |         """ Convenience? """
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| 434 | 
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| 435 |     # def AddNewObject(self, obj):
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| 436 |     def Add(self, obj):
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| 437 |         # type: (Any) -> None
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| 438 |         """
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| 439 |         Assert it isn't already there, and assign a new ID!
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| 440 | 
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| 441 |         # Lib/pickle does:
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| 442 | 
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| 443 |             self.memo[id(obj)] = memo_len, obj
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| 444 | 
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| 445 |         I guess that's the object ID and a void*
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| 446 | 
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| 447 |         Then it does:
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| 448 | 
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| 449 |             x = self.memo.get(id(obj))
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| 450 | 
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| 451 |         and
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| 452 | 
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| 453 |             # If the object is already in the memo, this means it is
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| 454 |             # recursive. In this case, throw away everything we put on the
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| 455 |             # stack, and fetch the object back from the memo.
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| 456 |             if id(obj) in self.memo:
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| 457 |                 write(POP + self.get(self.memo[id(obj)][0]))
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| 458 | 
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| 459 |         BUT It only uses the numeric ID!
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| 460 |         """
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| 461 |         addr = id(obj)
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| 462 |         assert addr not in self.addresses
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| 463 |         self.addresses[addr] = len(self.addresses)
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| 464 | 
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| 465 |     def Get(self, obj):
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| 466 |         # type: (Any) -> int
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| 467 |         """
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| 468 |         Returns unique ID assigned
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| 469 | 
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| 470 |         Returns -1 if it doesn't exist?
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| 471 |         """
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| 472 |         addr = id(obj)
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| 473 |         return self.addresses.get(addr, -1)
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| 474 | 
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| 475 |     # Note: self.memo.clear() doesn't appear to be used
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| 476 | 
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| 477 | 
 | 
| 478 | def probe(provider, name, *args):
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| 479 |     # type: (str, str, Any) -> None
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| 480 |     """Create a probe for use with profilers like linux perf and ebpf or dtrace."""
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| 481 |     # Noop. Just a marker for mycpp to emit a DTRACE_PROBE()
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| 482 |     return
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| 483 | 
 | 
| 484 | 
 | 
| 485 | if 0:
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| 486 |     # Prototype of Unix file descriptor I/O, compared with FILE* libc I/O.
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| 487 |     # Doesn't seem like we need this now.
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| 488 | 
 | 
| 489 |     # Short versions of STDOUT_FILENO and STDERR_FILENO
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| 490 |     kStdout = 1
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| 491 |     kStderr = 2
 | 
| 492 | 
 | 
| 493 |     def writeln(s, fd=kStdout):
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| 494 |         # type: (str, int) -> None
 | 
| 495 |         """Write a line.  The name is consistent with JavaScript writeln() and Rust.
 | 
| 496 | 
 | 
| 497 |         e.g.
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| 498 |         writeln("x = %d" % x, kStderr)
 | 
| 499 | 
 | 
| 500 |         TODO: The Oil interpreter shouldn't use print() anywhere.  Instead it can use
 | 
| 501 |         writeln(s) and writeln(s, kStderr)
 | 
| 502 |         """
 | 
| 503 |         posix.write(fd, s)
 | 
| 504 |         posix.write(fd, '\n')
 | 
| 505 | 
 | 
| 506 |     class File(object):
 | 
| 507 |         """Custom file wrapper for Unix I/O like write() read()
 | 
| 508 |     
 | 
| 509 |         Not C I/O like fwrite() fread().  There should be no flush().
 | 
| 510 |         """
 | 
| 511 | 
 | 
| 512 |         def __init__(self, fd):
 | 
| 513 |             # type: (int) -> None
 | 
| 514 |             self.fd = fd
 | 
| 515 | 
 | 
| 516 |         def write(self, s):
 | 
| 517 |             # type: (str) -> None
 | 
| 518 |             posix.write(self.fd, s)
 | 
| 519 | 
 | 
| 520 |         def writeln(self, s):
 | 
| 521 |             # type: (str) -> None
 | 
| 522 |             writeln(s, fd=self.fd)
 |