source: titan/mediathek/localhoster/lib/python2.7/codeop.py @ 40114

Last change on this file since 40114 was 40094, checked in by obi, 5 years ago

tithek add yoztube-dl support

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1r"""Utilities to compile possibly incomplete Python source code.
2
3This module provides two interfaces, broadly similar to the builtin
4function compile(), which take program text, a filename and a 'mode'
5and:
6
7- Return code object if the command is complete and valid
8- Return None if the command is incomplete
9- Raise SyntaxError, ValueError or OverflowError if the command is a
10  syntax error (OverflowError and ValueError can be produced by
11  malformed literals).
12
13Approach:
14
15First, check if the source consists entirely of blank lines and
16comments; if so, replace it with 'pass', because the built-in
17parser doesn't always do the right thing for these.
18
19Compile three times: as is, with \n, and with \n\n appended.  If it
20compiles as is, it's complete.  If it compiles with one \n appended,
21we expect more.  If it doesn't compile either way, we compare the
22error we get when compiling with \n or \n\n appended.  If the errors
23are the same, the code is broken.  But if the errors are different, we
24expect more.  Not intuitive; not even guaranteed to hold in future
25releases; but this matches the compiler's behavior from Python 1.4
26through 2.2, at least.
27
28Caveat:
29
30It is possible (but not likely) that the parser stops parsing with a
31successful outcome before reaching the end of the source; in this
32case, trailing symbols may be ignored instead of causing an error.
33For example, a backslash followed by two newlines may be followed by
34arbitrary garbage.  This will be fixed once the API for the parser is
35better.
36
37The two interfaces are:
38
39compile_command(source, filename, symbol):
40
41    Compiles a single command in the manner described above.
42
43CommandCompiler():
44
45    Instances of this class have __call__ methods identical in
46    signature to compile_command; the difference is that if the
47    instance compiles program text containing a __future__ statement,
48    the instance 'remembers' and compiles all subsequent program texts
49    with the statement in force.
50
51The module also provides another class:
52
53Compile():
54
55    Instances of this class act like the built-in function compile,
56    but with 'memory' in the sense described above.
57"""
58
59import __future__
60
61_features = [getattr(__future__, fname)
62             for fname in __future__.all_feature_names]
63
64__all__ = ["compile_command", "Compile", "CommandCompiler"]
65
66PyCF_DONT_IMPLY_DEDENT = 0x200          # Matches pythonrun.h
67
68def _maybe_compile(compiler, source, filename, symbol):
69    # Check for source consisting of only blank lines and comments
70    for line in source.split("\n"):
71        line = line.strip()
72        if line and line[0] != '#':
73            break               # Leave it alone
74    else:
75        if symbol != "eval":
76            source = "pass"     # Replace it with a 'pass' statement
77
78    err = err1 = err2 = None
79    code = code1 = code2 = None
80
81    try:
82        code = compiler(source, filename, symbol)
83    except SyntaxError, err:
84        pass
85
86    try:
87        code1 = compiler(source + "\n", filename, symbol)
88    except SyntaxError, err1:
89        pass
90
91    try:
92        code2 = compiler(source + "\n\n", filename, symbol)
93    except SyntaxError, err2:
94        pass
95
96    if code:
97        return code
98    if not code1 and repr(err1) == repr(err2):
99        raise SyntaxError, err1
100
101def _compile(source, filename, symbol):
102    return compile(source, filename, symbol, PyCF_DONT_IMPLY_DEDENT)
103
104def compile_command(source, filename="<input>", symbol="single"):
105    r"""Compile a command and determine whether it is incomplete.
106
107    Arguments:
108
109    source -- the source string; may contain \n characters
110    filename -- optional filename from which source was read; default
111                "<input>"
112    symbol -- optional grammar start symbol; "single" (default) or "eval"
113
114    Return value / exceptions raised:
115
116    - Return a code object if the command is complete and valid
117    - Return None if the command is incomplete
118    - Raise SyntaxError, ValueError or OverflowError if the command is a
119      syntax error (OverflowError and ValueError can be produced by
120      malformed literals).
121    """
122    return _maybe_compile(_compile, source, filename, symbol)
123
124class Compile:
125    """Instances of this class behave much like the built-in compile
126    function, but if one is used to compile text containing a future
127    statement, it "remembers" and compiles all subsequent program texts
128    with the statement in force."""
129    def __init__(self):
130        self.flags = PyCF_DONT_IMPLY_DEDENT
131
132    def __call__(self, source, filename, symbol):
133        codeob = compile(source, filename, symbol, self.flags, 1)
134        for feature in _features:
135            if codeob.co_flags & feature.compiler_flag:
136                self.flags |= feature.compiler_flag
137        return codeob
138
139class CommandCompiler:
140    """Instances of this class have __call__ methods identical in
141    signature to compile_command; the difference is that if the
142    instance compiles program text containing a __future__ statement,
143    the instance 'remembers' and compiles all subsequent program texts
144    with the statement in force."""
145
146    def __init__(self,):
147        self.compiler = Compile()
148
149    def __call__(self, source, filename="<input>", symbol="single"):
150        r"""Compile a command and determine whether it is incomplete.
151
152        Arguments:
153
154        source -- the source string; may contain \n characters
155        filename -- optional filename from which source was read;
156                    default "<input>"
157        symbol -- optional grammar start symbol; "single" (default) or
158                  "eval"
159
160        Return value / exceptions raised:
161
162        - Return a code object if the command is complete and valid
163        - Return None if the command is incomplete
164        - Raise SyntaxError, ValueError or OverflowError if the command is a
165          syntax error (OverflowError and ValueError can be produced by
166          malformed literals).
167        """
168        return _maybe_compile(self.compiler, source, filename, symbol)
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