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1 | ''' A decorator-based method of constructing IPython magics with `argparse` |
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1 | ''' A decorator-based method of constructing IPython magics with `argparse` | |
2 | option handling. |
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2 | option handling. | |
3 |
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3 | |||
4 | New magic functions can be defined like so:: |
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4 | New magic functions can be defined like so:: | |
5 |
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5 | |||
6 | from IPython.core.magic_arguments import (argument, magic_arguments, |
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6 | from IPython.core.magic_arguments import (argument, magic_arguments, | |
7 | parse_argstring) |
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7 | parse_argstring) | |
8 |
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8 | |||
9 | @magic_arguments() |
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9 | @magic_arguments() | |
10 | @argument('-o', '--option', help='An optional argument.') |
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10 | @argument('-o', '--option', help='An optional argument.') | |
11 | @argument('arg', type=int, help='An integer positional argument.') |
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11 | @argument('arg', type=int, help='An integer positional argument.') | |
12 | def magic_cool(self, arg): |
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12 | def magic_cool(self, arg): | |
13 | """ A really cool magic command. |
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13 | """ A really cool magic command. | |
14 |
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14 | |||
15 | """ |
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15 | """ | |
16 | args = parse_argstring(magic_cool, arg) |
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16 | args = parse_argstring(magic_cool, arg) | |
17 | ... |
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17 | ... | |
18 |
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18 | |||
19 | The `@magic_arguments` decorator marks the function as having argparse arguments. |
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19 | The `@magic_arguments` decorator marks the function as having argparse arguments. | |
20 | The `@argument` decorator adds an argument using the same syntax as argparse's |
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20 | The `@argument` decorator adds an argument using the same syntax as argparse's | |
21 | `add_argument()` method. More sophisticated uses may also require the |
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21 | `add_argument()` method. More sophisticated uses may also require the | |
22 | `@argument_group` or `@kwds` decorator to customize the formatting and the |
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22 | `@argument_group` or `@kwds` decorator to customize the formatting and the | |
23 | parsing. |
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23 | parsing. | |
24 |
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24 | |||
25 | Help text for the magic is automatically generated from the docstring and the |
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25 | Help text for the magic is automatically generated from the docstring and the | |
26 | arguments:: |
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26 | arguments:: | |
27 |
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27 | |||
28 | In[1]: %cool? |
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28 | In[1]: %cool? | |
29 | %cool [-o OPTION] arg |
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29 | %cool [-o OPTION] arg | |
30 |
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30 | |||
31 | A really cool magic command. |
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31 | A really cool magic command. | |
32 |
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32 | |||
33 | positional arguments: |
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33 | positional arguments: | |
34 | arg An integer positional argument. |
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34 | arg An integer positional argument. | |
35 |
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35 | |||
36 | optional arguments: |
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36 | optional arguments: | |
37 | -o OPTION, --option OPTION |
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37 | -o OPTION, --option OPTION | |
38 | An optional argument. |
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38 | An optional argument. | |
39 |
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39 | |||
40 | ''' |
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40 | ''' | |
41 | #----------------------------------------------------------------------------- |
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41 | #----------------------------------------------------------------------------- | |
42 | # Copyright (C) 2010-2011, IPython Development Team. |
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42 | # Copyright (C) 2010-2011, IPython Development Team. | |
43 | # |
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43 | # | |
44 | # Distributed under the terms of the Modified BSD License. |
|
44 | # Distributed under the terms of the Modified BSD License. | |
45 | # |
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45 | # | |
46 | # The full license is in the file COPYING.txt, distributed with this software. |
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46 | # The full license is in the file COPYING.txt, distributed with this software. | |
47 | #----------------------------------------------------------------------------- |
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47 | #----------------------------------------------------------------------------- | |
48 |
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48 | |||
49 | # Our own imports |
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49 | # Our own imports | |
50 | from IPython.external import argparse |
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50 | from IPython.external import argparse | |
51 | from IPython.core.error import UsageError |
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51 | from IPython.core.error import UsageError | |
52 | from IPython.utils.process import arg_split |
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52 | from IPython.utils.process import arg_split | |
53 | from IPython.utils.text import dedent |
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53 | from IPython.utils.text import dedent | |
54 |
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54 | |||
55 | class MagicHelpFormatter(argparse.RawDescriptionHelpFormatter): |
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55 | class MagicHelpFormatter(argparse.RawDescriptionHelpFormatter): | |
56 | """ A HelpFormatter which dedents but otherwise preserves indentation. |
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56 | """ A HelpFormatter which dedents but otherwise preserves indentation. | |
57 | """ |
|
57 | """ | |
58 | def _fill_text(self, text, width, indent): |
|
58 | def _fill_text(self, text, width, indent): | |
59 | return argparse.RawDescriptionHelpFormatter._fill_text(self, dedent(text), width, indent) |
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59 | return argparse.RawDescriptionHelpFormatter._fill_text(self, dedent(text), width, indent) | |
60 |
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60 | |||
61 | class MagicArgumentParser(argparse.ArgumentParser): |
|
61 | class MagicArgumentParser(argparse.ArgumentParser): | |
62 | """ An ArgumentParser tweaked for use by IPython magics. |
|
62 | """ An ArgumentParser tweaked for use by IPython magics. | |
63 | """ |
|
63 | """ | |
64 | def __init__(self, |
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64 | def __init__(self, | |
65 | prog=None, |
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65 | prog=None, | |
66 | usage=None, |
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66 | usage=None, | |
67 | description=None, |
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67 | description=None, | |
68 | epilog=None, |
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68 | epilog=None, | |
69 | version=None, |
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70 | parents=None, |
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69 | parents=None, | |
71 | formatter_class=MagicHelpFormatter, |
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70 | formatter_class=MagicHelpFormatter, | |
72 | prefix_chars='-', |
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71 | prefix_chars='-', | |
73 | argument_default=None, |
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72 | argument_default=None, | |
74 | conflict_handler='error', |
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73 | conflict_handler='error', | |
75 | add_help=False): |
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74 | add_help=False): | |
76 | if parents is None: |
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75 | if parents is None: | |
77 | parents = [] |
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76 | parents = [] | |
78 | super(MagicArgumentParser, self).__init__(prog=prog, usage=usage, |
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77 | super(MagicArgumentParser, self).__init__(prog=prog, usage=usage, | |
79 |
description=description, epilog=epilog, |
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78 | description=description, epilog=epilog, | |
80 | parents=parents, formatter_class=formatter_class, |
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79 | parents=parents, formatter_class=formatter_class, | |
81 | prefix_chars=prefix_chars, argument_default=argument_default, |
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80 | prefix_chars=prefix_chars, argument_default=argument_default, | |
82 | conflict_handler=conflict_handler, add_help=add_help) |
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81 | conflict_handler=conflict_handler, add_help=add_help) | |
83 |
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82 | |||
84 | def error(self, message): |
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83 | def error(self, message): | |
85 | """ Raise a catchable error instead of exiting. |
|
84 | """ Raise a catchable error instead of exiting. | |
86 | """ |
|
85 | """ | |
87 | raise UsageError(message) |
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86 | raise UsageError(message) | |
88 |
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87 | |||
89 | def parse_argstring(self, argstring): |
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88 | def parse_argstring(self, argstring): | |
90 | """ Split a string into an argument list and parse that argument list. |
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89 | """ Split a string into an argument list and parse that argument list. | |
91 | """ |
|
90 | """ | |
92 | argv = arg_split(argstring) |
|
91 | argv = arg_split(argstring) | |
93 | return self.parse_args(argv) |
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92 | return self.parse_args(argv) | |
94 |
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93 | |||
95 |
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94 | |||
96 | def construct_parser(magic_func): |
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95 | def construct_parser(magic_func): | |
97 | """ Construct an argument parser using the function decorations. |
|
96 | """ Construct an argument parser using the function decorations. | |
98 | """ |
|
97 | """ | |
99 | kwds = getattr(magic_func, 'argcmd_kwds', {}) |
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98 | kwds = getattr(magic_func, 'argcmd_kwds', {}) | |
100 | if 'description' not in kwds: |
|
99 | if 'description' not in kwds: | |
101 | kwds['description'] = getattr(magic_func, '__doc__', None) |
|
100 | kwds['description'] = getattr(magic_func, '__doc__', None) | |
102 | arg_name = real_name(magic_func) |
|
101 | arg_name = real_name(magic_func) | |
103 | parser = MagicArgumentParser(arg_name, **kwds) |
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102 | parser = MagicArgumentParser(arg_name, **kwds) | |
104 | # Reverse the list of decorators in order to apply them in the |
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103 | # Reverse the list of decorators in order to apply them in the | |
105 | # order in which they appear in the source. |
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104 | # order in which they appear in the source. | |
106 | group = None |
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105 | group = None | |
107 | for deco in magic_func.decorators[::-1]: |
|
106 | for deco in magic_func.decorators[::-1]: | |
108 | result = deco.add_to_parser(parser, group) |
|
107 | result = deco.add_to_parser(parser, group) | |
109 | if result is not None: |
|
108 | if result is not None: | |
110 | group = result |
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109 | group = result | |
111 |
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110 | |||
112 | # Replace the starting 'usage: ' with IPython's %. |
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111 | # Replace the starting 'usage: ' with IPython's %. | |
113 | help_text = parser.format_help() |
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112 | help_text = parser.format_help() | |
114 | if help_text.startswith('usage: '): |
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113 | if help_text.startswith('usage: '): | |
115 | help_text = help_text.replace('usage: ', '%', 1) |
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114 | help_text = help_text.replace('usage: ', '%', 1) | |
116 | else: |
|
115 | else: | |
117 | help_text = '%' + help_text |
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116 | help_text = '%' + help_text | |
118 |
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117 | |||
119 | # Replace the magic function's docstring with the full help text. |
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118 | # Replace the magic function's docstring with the full help text. | |
120 | magic_func.__doc__ = help_text |
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119 | magic_func.__doc__ = help_text | |
121 |
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120 | |||
122 | return parser |
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121 | return parser | |
123 |
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122 | |||
124 |
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123 | |||
125 | def parse_argstring(magic_func, argstring): |
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124 | def parse_argstring(magic_func, argstring): | |
126 | """ Parse the string of arguments for the given magic function. |
|
125 | """ Parse the string of arguments for the given magic function. | |
127 | """ |
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126 | """ | |
128 | return magic_func.parser.parse_argstring(argstring) |
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127 | return magic_func.parser.parse_argstring(argstring) | |
129 |
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128 | |||
130 |
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129 | |||
131 | def real_name(magic_func): |
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130 | def real_name(magic_func): | |
132 | """ Find the real name of the magic. |
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131 | """ Find the real name of the magic. | |
133 | """ |
|
132 | """ | |
134 | magic_name = magic_func.__name__ |
|
133 | magic_name = magic_func.__name__ | |
135 | if magic_name.startswith('magic_'): |
|
134 | if magic_name.startswith('magic_'): | |
136 | magic_name = magic_name[len('magic_'):] |
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135 | magic_name = magic_name[len('magic_'):] | |
137 | return getattr(magic_func, 'argcmd_name', magic_name) |
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136 | return getattr(magic_func, 'argcmd_name', magic_name) | |
138 |
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137 | |||
139 |
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138 | |||
140 | class ArgDecorator(object): |
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139 | class ArgDecorator(object): | |
141 | """ Base class for decorators to add ArgumentParser information to a method. |
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140 | """ Base class for decorators to add ArgumentParser information to a method. | |
142 | """ |
|
141 | """ | |
143 |
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142 | |||
144 | def __call__(self, func): |
|
143 | def __call__(self, func): | |
145 | if not getattr(func, 'has_arguments', False): |
|
144 | if not getattr(func, 'has_arguments', False): | |
146 | func.has_arguments = True |
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145 | func.has_arguments = True | |
147 | func.decorators = [] |
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146 | func.decorators = [] | |
148 | func.decorators.append(self) |
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147 | func.decorators.append(self) | |
149 | return func |
|
148 | return func | |
150 |
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149 | |||
151 | def add_to_parser(self, parser, group): |
|
150 | def add_to_parser(self, parser, group): | |
152 | """ Add this object's information to the parser, if necessary. |
|
151 | """ Add this object's information to the parser, if necessary. | |
153 | """ |
|
152 | """ | |
154 | pass |
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153 | pass | |
155 |
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154 | |||
156 |
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155 | |||
157 | class magic_arguments(ArgDecorator): |
|
156 | class magic_arguments(ArgDecorator): | |
158 | """ Mark the magic as having argparse arguments and possibly adjust the |
|
157 | """ Mark the magic as having argparse arguments and possibly adjust the | |
159 | name. |
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158 | name. | |
160 | """ |
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159 | """ | |
161 |
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160 | |||
162 | def __init__(self, name=None): |
|
161 | def __init__(self, name=None): | |
163 | self.name = name |
|
162 | self.name = name | |
164 |
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163 | |||
165 | def __call__(self, func): |
|
164 | def __call__(self, func): | |
166 | if not getattr(func, 'has_arguments', False): |
|
165 | if not getattr(func, 'has_arguments', False): | |
167 | func.has_arguments = True |
|
166 | func.has_arguments = True | |
168 | func.decorators = [] |
|
167 | func.decorators = [] | |
169 | if self.name is not None: |
|
168 | if self.name is not None: | |
170 | func.argcmd_name = self.name |
|
169 | func.argcmd_name = self.name | |
171 | # This should be the first decorator in the list of decorators, thus the |
|
170 | # This should be the first decorator in the list of decorators, thus the | |
172 | # last to execute. Build the parser. |
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171 | # last to execute. Build the parser. | |
173 | func.parser = construct_parser(func) |
|
172 | func.parser = construct_parser(func) | |
174 | return func |
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173 | return func | |
175 |
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174 | |||
176 |
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175 | |||
177 | class argument(ArgDecorator): |
|
176 | class argument(ArgDecorator): | |
178 | """ Store arguments and keywords to pass to add_argument(). |
|
177 | """ Store arguments and keywords to pass to add_argument(). | |
179 |
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178 | |||
180 | Instances also serve to decorate command methods. |
|
179 | Instances also serve to decorate command methods. | |
181 | """ |
|
180 | """ | |
182 | def __init__(self, *args, **kwds): |
|
181 | def __init__(self, *args, **kwds): | |
183 | self.args = args |
|
182 | self.args = args | |
184 | self.kwds = kwds |
|
183 | self.kwds = kwds | |
185 |
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184 | |||
186 | def add_to_parser(self, parser, group): |
|
185 | def add_to_parser(self, parser, group): | |
187 | """ Add this object's information to the parser. |
|
186 | """ Add this object's information to the parser. | |
188 | """ |
|
187 | """ | |
189 | if group is not None: |
|
188 | if group is not None: | |
190 | parser = group |
|
189 | parser = group | |
191 | parser.add_argument(*self.args, **self.kwds) |
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190 | parser.add_argument(*self.args, **self.kwds) | |
192 | return None |
|
191 | return None | |
193 |
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192 | |||
194 |
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193 | |||
195 | class argument_group(ArgDecorator): |
|
194 | class argument_group(ArgDecorator): | |
196 | """ Store arguments and keywords to pass to add_argument_group(). |
|
195 | """ Store arguments and keywords to pass to add_argument_group(). | |
197 |
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196 | |||
198 | Instances also serve to decorate command methods. |
|
197 | Instances also serve to decorate command methods. | |
199 | """ |
|
198 | """ | |
200 | def __init__(self, *args, **kwds): |
|
199 | def __init__(self, *args, **kwds): | |
201 | self.args = args |
|
200 | self.args = args | |
202 | self.kwds = kwds |
|
201 | self.kwds = kwds | |
203 |
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202 | |||
204 | def add_to_parser(self, parser, group): |
|
203 | def add_to_parser(self, parser, group): | |
205 | """ Add this object's information to the parser. |
|
204 | """ Add this object's information to the parser. | |
206 | """ |
|
205 | """ | |
207 | return parser.add_argument_group(*self.args, **self.kwds) |
|
206 | return parser.add_argument_group(*self.args, **self.kwds) | |
208 |
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207 | |||
209 |
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208 | |||
210 | class kwds(ArgDecorator): |
|
209 | class kwds(ArgDecorator): | |
211 | """ Provide other keywords to the sub-parser constructor. |
|
210 | """ Provide other keywords to the sub-parser constructor. | |
212 | """ |
|
211 | """ | |
213 | def __init__(self, **kwds): |
|
212 | def __init__(self, **kwds): | |
214 | self.kwds = kwds |
|
213 | self.kwds = kwds | |
215 |
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214 | |||
216 | def __call__(self, func): |
|
215 | def __call__(self, func): | |
217 | func = super(kwds, self).__call__(func) |
|
216 | func = super(kwds, self).__call__(func) | |
218 | func.argcmd_kwds = self.kwds |
|
217 | func.argcmd_kwds = self.kwds | |
219 | return func |
|
218 | return func | |
220 |
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219 | |||
221 |
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220 | |||
222 | __all__ = ['magic_arguments', 'argument', 'argument_group', 'kwds', |
|
221 | __all__ = ['magic_arguments', 'argument', 'argument_group', 'kwds', | |
223 | 'parse_argstring'] |
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222 | 'parse_argstring'] |
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