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1 | 1 | # encoding: utf-8 |
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2 | 2 | """ |
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3 | 3 | IO related utilities. |
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4 | 4 | """ |
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5 | 5 | |
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6 | 6 | #----------------------------------------------------------------------------- |
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7 | 7 | # Copyright (C) 2008-2011 The IPython Development Team |
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8 | 8 | # |
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9 | 9 | # Distributed under the terms of the BSD License. The full license is in |
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10 | 10 | # the file COPYING, distributed as part of this software. |
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11 | 11 | #----------------------------------------------------------------------------- |
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12 | 12 | from __future__ import print_function |
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13 | 13 | |
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14 | 14 | #----------------------------------------------------------------------------- |
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15 | 15 | # Imports |
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16 | 16 | #----------------------------------------------------------------------------- |
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17 | 17 | import os |
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18 | 18 | import sys |
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19 | 19 | import tempfile |
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20 | 20 | from StringIO import StringIO |
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21 | 21 | |
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22 | 22 | #----------------------------------------------------------------------------- |
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23 | 23 | # Code |
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24 | 24 | #----------------------------------------------------------------------------- |
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25 | 25 | |
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26 | 26 | |
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27 | 27 | class IOStream: |
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28 | 28 | |
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29 | 29 | def __init__(self,stream, fallback=None): |
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30 | 30 | if not hasattr(stream,'write') or not hasattr(stream,'flush'): |
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31 | 31 | if fallback is not None: |
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32 | 32 | stream = fallback |
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33 | 33 | else: |
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34 | 34 | raise ValueError("fallback required, but not specified") |
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35 | 35 | self.stream = stream |
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36 | 36 | self._swrite = stream.write |
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37 | 37 | |
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38 | 38 | # clone all methods not overridden: |
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39 | 39 | def clone(meth): |
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40 | 40 | return not hasattr(self, meth) and not meth.startswith('_') |
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41 | 41 | for meth in filter(clone, dir(stream)): |
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42 | 42 | setattr(self, meth, getattr(stream, meth)) |
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43 | 43 | |
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44 | 44 | def write(self,data): |
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45 | 45 | try: |
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46 | 46 | self._swrite(data) |
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47 | 47 | except: |
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48 | 48 | try: |
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49 | 49 | # print handles some unicode issues which may trip a plain |
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50 | 50 | # write() call. Emulate write() by using an empty end |
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51 | 51 | # argument. |
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52 | 52 | print(data, end='', file=self.stream) |
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53 | 53 | except: |
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54 | 54 | # if we get here, something is seriously broken. |
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55 | 55 | print('ERROR - failed to write data to stream:', self.stream, |
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56 | 56 | file=sys.stderr) |
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57 | 57 | |
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58 | 58 | def writelines(self, lines): |
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59 | 59 | if isinstance(lines, basestring): |
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60 | 60 | lines = [lines] |
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61 | 61 | for line in lines: |
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62 | 62 | self.write(line) |
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63 | 63 | |
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64 | 64 | # This class used to have a writeln method, but regular files and streams |
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65 | 65 | # in Python don't have this method. We need to keep this completely |
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66 | 66 | # compatible so we removed it. |
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67 | 67 | |
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68 | 68 | @property |
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69 | 69 | def closed(self): |
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70 | 70 | return self.stream.closed |
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71 | 71 | |
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72 | 72 | def close(self): |
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73 | 73 | pass |
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74 | 74 | |
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75 | 75 | # setup stdin/stdout/stderr to sys.stdin/sys.stdout/sys.stderr |
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76 | 76 | devnull = open(os.devnull, 'a') |
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77 | 77 | stdin = IOStream(sys.stdin, fallback=devnull) |
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78 | 78 | stdout = IOStream(sys.stdout, fallback=devnull) |
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79 | 79 | stderr = IOStream(sys.stderr, fallback=devnull) |
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80 | 80 | |
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81 | 81 | class IOTerm: |
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82 | 82 | """ Term holds the file or file-like objects for handling I/O operations. |
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83 | 83 | |
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84 | 84 | These are normally just sys.stdin, sys.stdout and sys.stderr but for |
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85 | 85 | Windows they can can replaced to allow editing the strings before they are |
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86 | 86 | displayed.""" |
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87 | 87 | |
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88 | 88 | # In the future, having IPython channel all its I/O operations through |
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89 | 89 | # this class will make it easier to embed it into other environments which |
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90 | 90 | # are not a normal terminal (such as a GUI-based shell) |
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91 | 91 | def __init__(self, stdin=None, stdout=None, stderr=None): |
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92 | 92 | mymodule = sys.modules[__name__] |
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93 | 93 | self.stdin = IOStream(stdin, mymodule.stdin) |
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94 | 94 | self.stdout = IOStream(stdout, mymodule.stdout) |
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95 | 95 | self.stderr = IOStream(stderr, mymodule.stderr) |
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96 | 96 | |
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97 | 97 | |
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98 | 98 | class Tee(object): |
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99 | 99 | """A class to duplicate an output stream to stdout/err. |
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100 | 100 | |
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101 | 101 | This works in a manner very similar to the Unix 'tee' command. |
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102 | 102 | |
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103 | 103 | When the object is closed or deleted, it closes the original file given to |
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104 | 104 | it for duplication. |
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105 | 105 | """ |
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106 | 106 | # Inspired by: |
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107 | 107 | # http://mail.python.org/pipermail/python-list/2007-May/442737.html |
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108 | 108 | |
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109 | 109 | def __init__(self, file_or_name, mode="w", channel='stdout'): |
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110 | 110 | """Construct a new Tee object. |
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111 | 111 | |
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112 | 112 | Parameters |
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113 | 113 | ---------- |
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114 | 114 | file_or_name : filename or open filehandle (writable) |
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115 | 115 | File that will be duplicated |
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116 | 116 | |
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117 | 117 | mode : optional, valid mode for open(). |
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118 | 118 | If a filename was give, open with this mode. |
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119 | 119 | |
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120 | 120 | channel : str, one of ['stdout', 'stderr'] |
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121 | 121 | """ |
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122 | 122 | if channel not in ['stdout', 'stderr']: |
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123 | 123 | raise ValueError('Invalid channel spec %s' % channel) |
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124 | 124 | |
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125 | 125 | if hasattr(file_or_name, 'write') and hasattr(file_or_name, 'seek'): |
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126 | 126 | self.file = file_or_name |
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127 | 127 | else: |
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128 | 128 | self.file = open(file_or_name, mode) |
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129 | 129 | self.channel = channel |
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130 | 130 | self.ostream = getattr(sys, channel) |
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131 | 131 | setattr(sys, channel, self) |
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132 | 132 | self._closed = False |
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133 | 133 | |
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134 | 134 | def close(self): |
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135 | 135 | """Close the file and restore the channel.""" |
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136 | 136 | self.flush() |
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137 | 137 | setattr(sys, self.channel, self.ostream) |
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138 | 138 | self.file.close() |
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139 | 139 | self._closed = True |
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140 | 140 | |
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141 | 141 | def write(self, data): |
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142 | 142 | """Write data to both channels.""" |
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143 | 143 | self.file.write(data) |
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144 | 144 | self.ostream.write(data) |
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145 | 145 | self.ostream.flush() |
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146 | 146 | |
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147 | 147 | def flush(self): |
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148 | 148 | """Flush both channels.""" |
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149 | 149 | self.file.flush() |
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150 | 150 | self.ostream.flush() |
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151 | 151 | |
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152 | 152 | def __del__(self): |
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153 | 153 | if not self._closed: |
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154 | 154 | self.close() |
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155 | 155 | |
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156 | 156 | |
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157 | 157 | def file_read(filename): |
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158 | 158 | """Read a file and close it. Returns the file source.""" |
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159 | 159 | fobj = open(filename,'r'); |
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160 | 160 | source = fobj.read(); |
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161 | 161 | fobj.close() |
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162 | 162 | return source |
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163 | 163 | |
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164 | 164 | |
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165 | 165 | def file_readlines(filename): |
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166 | 166 | """Read a file and close it. Returns the file source using readlines().""" |
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167 | 167 | fobj = open(filename,'r'); |
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168 | 168 | lines = fobj.readlines(); |
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169 | 169 | fobj.close() |
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170 | 170 | return lines |
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171 | 171 | |
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172 | 172 | |
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173 | 173 | def raw_input_multi(header='', ps1='==> ', ps2='..> ',terminate_str = '.'): |
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174 | 174 | """Take multiple lines of input. |
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175 | 175 | |
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176 | 176 | A list with each line of input as a separate element is returned when a |
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177 | 177 | termination string is entered (defaults to a single '.'). Input can also |
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178 | 178 | terminate via EOF (^D in Unix, ^Z-RET in Windows). |
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179 | 179 | |
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180 | 180 | Lines of input which end in \\ are joined into single entries (and a |
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181 | 181 | secondary continuation prompt is issued as long as the user terminates |
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182 | 182 | lines with \\). This allows entering very long strings which are still |
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183 | 183 | meant to be treated as single entities. |
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184 | 184 | """ |
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185 | 185 | |
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186 | 186 | try: |
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187 | 187 | if header: |
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188 | 188 | header += '\n' |
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189 | 189 | lines = [raw_input(header + ps1)] |
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190 | 190 | except EOFError: |
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191 | 191 | return [] |
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192 | 192 | terminate = [terminate_str] |
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193 | 193 | try: |
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194 | 194 | while lines[-1:] != terminate: |
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195 | 195 | new_line = raw_input(ps1) |
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196 | 196 | while new_line.endswith('\\'): |
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197 | 197 | new_line = new_line[:-1] + raw_input(ps2) |
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198 | 198 | lines.append(new_line) |
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199 | 199 | |
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200 | 200 | return lines[:-1] # don't return the termination command |
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201 | 201 | except EOFError: |
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202 | 202 | print() |
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203 | 203 | return lines |
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204 | 204 | |
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205 | 205 | |
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206 | 206 | def raw_input_ext(prompt='', ps2='... '): |
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207 | 207 | """Similar to raw_input(), but accepts extended lines if input ends with \\.""" |
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208 | 208 | |
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209 | 209 | line = raw_input(prompt) |
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210 | 210 | while line.endswith('\\'): |
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211 | 211 | line = line[:-1] + raw_input(ps2) |
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212 | 212 | return line |
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213 | 213 | |
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214 | 214 | |
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215 | 215 | def ask_yes_no(prompt,default=None): |
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216 | 216 | """Asks a question and returns a boolean (y/n) answer. |
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217 | 217 | |
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218 | 218 | If default is given (one of 'y','n'), it is used if the user input is |
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219 | 219 | empty. Otherwise the question is repeated until an answer is given. |
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220 | 220 | |
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221 | 221 | An EOF is treated as the default answer. If there is no default, an |
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222 | 222 | exception is raised to prevent infinite loops. |
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223 | 223 | |
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224 | 224 | Valid answers are: y/yes/n/no (match is not case sensitive).""" |
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225 | 225 | |
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226 | 226 | answers = {'y':True,'n':False,'yes':True,'no':False} |
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227 | 227 | ans = None |
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228 | 228 | while ans not in answers.keys(): |
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229 | 229 | try: |
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230 | 230 | ans = raw_input(prompt+' ').lower() |
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231 | 231 | if not ans: # response was an empty string |
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232 | 232 | ans = default |
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233 | 233 | except KeyboardInterrupt: |
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234 | 234 | pass |
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235 | 235 | except EOFError: |
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236 | 236 | if default in answers.keys(): |
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237 | 237 | ans = default |
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238 | 238 | print() |
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239 | 239 | else: |
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240 | 240 | raise |
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241 | 241 | |
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242 | 242 | return answers[ans] |
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243 | 243 | |
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244 | 244 | |
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245 | 245 | class NLprinter: |
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246 | 246 | """Print an arbitrarily nested list, indicating index numbers. |
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247 | 247 | |
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248 | 248 | An instance of this class called nlprint is available and callable as a |
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249 | 249 | function. |
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250 | 250 | |
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251 | 251 | nlprint(list,indent=' ',sep=': ') -> prints indenting each level by 'indent' |
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252 | 252 | and using 'sep' to separate the index from the value. """ |
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253 | 253 | |
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254 | 254 | def __init__(self): |
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255 | 255 | self.depth = 0 |
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256 | 256 | |
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257 | 257 | def __call__(self,lst,pos='',**kw): |
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258 | 258 | """Prints the nested list numbering levels.""" |
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259 | 259 | kw.setdefault('indent',' ') |
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260 | 260 | kw.setdefault('sep',': ') |
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261 | 261 | kw.setdefault('start',0) |
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262 | 262 | kw.setdefault('stop',len(lst)) |
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263 | 263 | # we need to remove start and stop from kw so they don't propagate |
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264 | 264 | # into a recursive call for a nested list. |
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265 | 265 | start = kw['start']; del kw['start'] |
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266 | 266 | stop = kw['stop']; del kw['stop'] |
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267 | 267 | if self.depth == 0 and 'header' in kw.keys(): |
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268 | 268 | print(kw['header']) |
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269 | 269 | |
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270 | 270 | for idx in range(start,stop): |
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271 | 271 | elem = lst[idx] |
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272 | 272 | newpos = pos + str(idx) |
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273 | 273 | if type(elem)==type([]): |
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274 | 274 | self.depth += 1 |
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275 | 275 | self.__call__(elem, newpos+",", **kw) |
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276 | 276 | self.depth -= 1 |
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277 | 277 | else: |
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278 | 278 | print(kw['indent']*self.depth + newpos + kw["sep"] + repr(elem)) |
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279 | 279 | |
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280 | 280 | nlprint = NLprinter() |
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281 | 281 | |
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282 | 282 | |
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283 | 283 | def temp_pyfile(src, ext='.py'): |
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284 | 284 | """Make a temporary python file, return filename and filehandle. |
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285 | 285 | |
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286 | 286 | Parameters |
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287 | 287 | ---------- |
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288 | 288 | src : string or list of strings (no need for ending newlines if list) |
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289 | 289 | Source code to be written to the file. |
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290 | 290 | |
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291 | 291 | ext : optional, string |
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292 | 292 | Extension for the generated file. |
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293 | 293 | |
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294 | 294 | Returns |
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295 | 295 | ------- |
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296 | 296 | (filename, open filehandle) |
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297 | 297 | It is the caller's responsibility to close the open file and unlink it. |
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298 | 298 | """ |
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299 | 299 | fname = tempfile.mkstemp(ext)[1] |
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300 | 300 | f = open(fname,'w') |
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301 | 301 | f.write(src) |
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302 | 302 | f.flush() |
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303 | 303 | return fname, f |
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304 | 304 | |
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305 | 305 | |
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306 | 306 | def raw_print(*args, **kw): |
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307 | 307 | """Raw print to sys.__stdout__, otherwise identical interface to print().""" |
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308 | 308 | |
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309 | 309 | print(*args, sep=kw.get('sep', ' '), end=kw.get('end', '\n'), |
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310 | 310 | file=sys.__stdout__) |
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311 | 311 | sys.__stdout__.flush() |
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312 | 312 | |
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313 | 313 | |
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314 | 314 | def raw_print_err(*args, **kw): |
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315 | 315 | """Raw print to sys.__stderr__, otherwise identical interface to print().""" |
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316 | 316 | |
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317 | 317 | print(*args, sep=kw.get('sep', ' '), end=kw.get('end', '\n'), |
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318 | 318 | file=sys.__stderr__) |
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319 | 319 | sys.__stderr__.flush() |
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320 | 320 | |
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321 | 321 | |
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322 | 322 | # Short aliases for quick debugging, do NOT use these in production code. |
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323 | 323 | rprint = raw_print |
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324 | 324 | rprinte = raw_print_err |
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325 | 325 | |
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326 | 326 | |
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327 | 327 | class CapturedIO(object): |
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328 | 328 | """Simple object for containing captured stdout/err StringIO objects""" |
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329 | 329 | |
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330 | 330 | def __init__(self, stdout, stderr): |
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331 | 331 | self._stdout = stdout |
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332 | 332 | self._stderr = stderr |
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333 | 333 | |
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334 | def __str__(self): | |
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335 | return self.stdout | |
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336 | ||
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334 | 337 | @property |
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335 | 338 | def stdout(self): |
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336 | 339 | if not self._stdout: |
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337 | 340 | return '' |
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338 | 341 | return self._stdout.getvalue() |
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339 | 342 | |
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340 | 343 | @property |
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341 | 344 | def stderr(self): |
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342 | 345 | if not self._stderr: |
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343 | 346 | return '' |
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344 | 347 | return self._stderr.getvalue() |
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345 | 348 | |
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346 | 349 | def show(self): |
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347 | 350 | """write my output to sys.stdout/err as appropriate""" |
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348 | 351 | sys.stdout.write(self.stdout) |
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349 | 352 | sys.stderr.write(self.stderr) |
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350 | 353 | sys.stdout.flush() |
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351 | 354 | sys.stderr.flush() |
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352 | 355 | |
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353 | 356 | __call__ = show |
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354 | 357 | |
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355 | 358 | |
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356 | 359 | class capture_output(object): |
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357 | 360 | """context manager for capturing stdout/err""" |
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358 | 361 | stdout = True |
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359 | 362 | stderr = True |
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360 | 363 | |
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361 | 364 | def __init__(self, stdout=True, stderr=True): |
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362 | 365 | self.stdout = stdout |
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363 | 366 | self.stderr = stderr |
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364 | 367 | |
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365 | 368 | def __enter__(self): |
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366 | 369 | self.sys_stdout = sys.stdout |
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367 | 370 | self.sys_stderr = sys.stderr |
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368 | 371 | |
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369 | 372 | stdout = stderr = False |
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370 | 373 | if self.stdout: |
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371 | 374 | stdout = sys.stdout = StringIO() |
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372 | 375 | if self.stderr: |
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373 | 376 | stderr = sys.stderr = StringIO() |
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374 | 377 | |
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375 | 378 | return CapturedIO(stdout, stderr) |
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376 | 379 | |
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377 | 380 | def __exit__(self, exc_type, exc_value, traceback): |
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378 | 381 | sys.stdout = self.sys_stdout |
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379 | 382 | sys.stderr = self.sys_stderr |
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380 | 383 | |
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381 | 384 |
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