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1 | 1 | # -*- coding: utf-8 -*- |
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2 | 2 | """Displayhook formatters. |
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3 | 3 | |
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4 | 4 | The DefaultFormatter is always present and may be configured from the |
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5 | 5 | ipython_config.py file. For example, to add a pretty-printer for a numpy.dtype |
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6 | 6 | object:: |
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7 | 7 | |
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8 | 8 | def dtype_pprinter(obj, p, cycle): |
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9 | 9 | if cycle: |
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10 | 10 | return p.text('dtype(...)') |
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11 | 11 | if hasattr(obj, 'fields'): |
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12 | 12 | if obj.fields is None: |
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13 | 13 | p.text(repr(obj)) |
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14 | 14 | else: |
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15 | 15 | p.begin_group(7, 'dtype([') |
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16 | 16 | for i, field in enumerate(obj.descr): |
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17 | 17 | if i > 0: |
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18 | 18 | p.text(',') |
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19 | 19 | p.breakable() |
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20 | 20 | p.pretty(field) |
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21 | 21 | p.end_group(7, '])') |
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22 | 22 | |
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23 | 23 | c.DefaultFormatter.deferred_pprinters = { |
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24 | 24 | ('numpy', 'dtype'): dtype_pprinter, |
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25 | 25 | } |
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26 | 26 | |
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27 | 27 | The deferred_pprinters dictionary is the preferred way to configure these |
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28 | 28 | pretty-printers. This allows you to define the pretty-printer without needing to |
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29 | 29 | import the type itself. The dictionary maps (modulename, typename) pairs to |
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30 | 30 | a function. |
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31 | 31 | |
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32 | 32 | See the `IPython.external.pretty` documentation for how to write |
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33 | 33 | pretty-printer functions. |
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34 | 34 | """ |
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35 | #----------------------------------------------------------------------------- | |
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36 | # Copyright (c) 2010, IPython Development Team. | |
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37 | # | |
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38 | # Distributed under the terms of the Modified BSD License. | |
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39 | # | |
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40 | # The full license is in the file COPYING.txt, distributed with this software. | |
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41 | #----------------------------------------------------------------------------- | |
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35 | 42 | |
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36 | 43 | # Stdlib imports |
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37 | 44 | import abc |
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38 | 45 | from cStringIO import StringIO |
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39 | 46 | |
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40 | 47 | # Our own imports |
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41 | 48 | from IPython.config.configurable import Configurable |
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42 | 49 | from IPython.external import pretty |
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43 | 50 | from IPython.utils.traitlets import Bool, Dict, Int, Str |
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44 | 51 | |
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45 | 52 | |
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46 | 53 | #----------------------------------------------------------------------------- |
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47 | 54 | # Classes and functions |
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48 | 55 | #----------------------------------------------------------------------------- |
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49 | 56 | |
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50 | 57 | class DefaultFormatter(Configurable): |
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51 | 58 | """ The default pretty-printer. |
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52 | 59 | """ |
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53 | 60 | |
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54 | 61 | # The ID of the formatter. |
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55 | 62 | id = Str('default') |
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56 | 63 | |
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57 | 64 | # The kind of data returned. |
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58 | 65 | # This is often, but not always a MIME type. |
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59 | 66 | format = Str('text/plain') |
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60 | 67 | |
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61 | 68 | # Whether to pretty-print or not. |
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62 | 69 | pprint = Bool(True, config=True) |
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63 | 70 | |
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64 | 71 | # Whether to be verbose or not. |
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65 | 72 | verbose = Bool(False, config=True) |
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66 | 73 | |
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67 | 74 | # The maximum width. |
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68 | 75 | max_width = Int(79, config=True) |
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69 | 76 | |
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70 | 77 | # The newline character. |
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71 | 78 | newline = Str('\n', config=True) |
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72 | 79 | |
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73 | 80 | # The singleton prettyprinters. |
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74 | 81 | # Maps the IDs of the builtin singleton objects to the format functions. |
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75 | 82 | singleton_pprinters = Dict(config=True) |
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76 | 83 | def _singleton_pprinters_default(self): |
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77 | 84 | return pretty._singleton_pprinters.copy() |
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78 | 85 | |
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79 | 86 | # The type-specific prettyprinters. |
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80 | 87 | # Map type objects to the format functions. |
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81 | 88 | type_pprinters = Dict(config=True) |
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82 | 89 | def _type_pprinters_default(self): |
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83 | 90 | return pretty._type_pprinters.copy() |
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84 | 91 | |
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85 | 92 | # The deferred-import type-specific prettyprinters. |
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86 | 93 | # Map (modulename, classname) pairs to the format functions. |
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87 | 94 | deferred_pprinters = Dict(config=True) |
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88 | 95 | def _deferred_pprinters_default(self): |
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89 | 96 | return pretty._deferred_type_pprinters.copy() |
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90 | 97 | |
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91 | 98 | #### FormatterABC interface #### |
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92 | 99 | |
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93 | 100 | def __call__(self, obj): |
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94 | 101 | """ Format the object. |
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95 | 102 | """ |
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96 | 103 | if not self.pprint: |
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97 | 104 | try: |
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98 | 105 | return repr(obj) |
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99 | 106 | except TypeError: |
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100 | 107 | return '' |
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101 | 108 | else: |
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102 | 109 | stream = StringIO() |
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103 | 110 | printer = pretty.RepresentationPrinter(stream, self.verbose, |
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104 | 111 | self.max_width, self.newline, |
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105 | 112 | singleton_pprinters=self.singleton_pprinters, |
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106 | 113 | type_pprinters=self.type_pprinters, |
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107 | 114 | deferred_pprinters=self.deferred_pprinters) |
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108 | 115 | printer.pretty(obj) |
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109 | 116 | printer.flush() |
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110 | 117 | return stream.getvalue() |
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111 | 118 | |
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112 | 119 | |
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113 | 120 | #### DefaultFormatter interface #### |
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114 | 121 | |
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115 | 122 | def for_type(self, typ, func): |
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116 | 123 | """ |
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117 | 124 | Add a pretty printer for a given type. |
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118 | 125 | """ |
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119 | 126 | oldfunc = self.type_pprinters.get(typ, None) |
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120 | 127 | if func is not None: |
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121 | 128 | # To support easy restoration of old pprinters, we need to ignore |
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122 | 129 | # Nones. |
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123 | 130 | self.type_pprinters[typ] = func |
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124 | 131 | return oldfunc |
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125 | 132 | |
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126 | 133 | def for_type_by_name(self, type_module, type_name, func): |
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127 | 134 | """ |
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128 | 135 | Add a pretty printer for a type specified by the module and name of |
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129 | 136 | a type rather than the type object itself. |
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130 | 137 | """ |
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131 | 138 | key = (type_module, type_name) |
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132 | 139 | oldfunc = self.deferred_pprinters.get(key, None) |
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133 | 140 | if func is not None: |
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134 | 141 | # To support easy restoration of old pprinters, we need to ignore |
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135 | 142 | # Nones. |
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136 | 143 | self.deferred_pprinters[key] = func |
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137 | 144 | return oldfunc |
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138 | 145 | |
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139 | 146 | |
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140 | 147 | class FormatterABC(object): |
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141 | 148 | """ Abstract base class for Formatters. |
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142 | 149 | """ |
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143 | 150 | __metaclass__ = abc.ABCMeta |
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144 | 151 | |
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145 | 152 | # The ID of the formatter. |
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146 | 153 | id = 'abstract' |
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147 | 154 | |
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148 | 155 | # The kind of data returned. |
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149 | 156 | format = 'text/plain' |
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150 | 157 | |
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151 | 158 | @abc.abstractmethod |
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152 | 159 | def __call__(self, obj): |
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153 | 160 | """ Return a JSONable representation of the object. |
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154 | 161 | |
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155 | 162 | If the object cannot be formatted by this formatter, then return None |
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156 | 163 | """ |
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157 | 164 | try: |
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158 | 165 | return repr(obj) |
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159 | 166 | except TypeError: |
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160 | 167 | return None |
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161 | 168 | |
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162 | 169 | FormatterABC.register(DefaultFormatter) |
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