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57 | 6.21.4.2 How callbacks are called | |
58 | </H3> | |
59 | ||
60 | <P> | |
61 | All callbacks are called as follows: | |
62 | <div class="verbatim"><pre> | |
63 | func(option, opt_str, value, parser, *args, **kwargs) | |
64 | </pre></div> | |
65 | ||
66 | <P> | |
67 | where | |
68 | <DL> | |
69 | <DT><STRONG><code>option</code></STRONG></DT> | |
70 | <DD>is the Option instance that's calling the callback | |
71 | </DD> | |
72 | <DT><STRONG><code>opt_str</code></STRONG></DT> | |
73 | <DD>is the option string seen on the command-line that's triggering the | |
74 | callback. (If an abbreviated long option was used, <code>opt_str</code> will | |
75 | be the full, canonical option string--e.g. if the user puts | |
76 | <code>"-foo"</code> on the command-line as an abbreviation for | |
77 | <code>"-foobar"</code>, then <code>opt_str</code> will be <code>"-foobar"</code>.) | |
78 | </DD> | |
79 | <DT><STRONG><code>value</code></STRONG></DT> | |
80 | <DD>is the argument to this option seen on the command-line. <tt class="module">optparse</tt> will | |
81 | only expect an argument if <tt class="member">type</tt> is set; the type of <code>value</code> | |
82 | will be the type implied by the option's type. If <tt class="member">type</tt> for this | |
83 | option is <code>None</code> (no argument expected), then <code>value</code> will be | |
84 | <code>None</code>. If <code>nargs</code> > 1, <code>value</code> will be a tuple of values of | |
85 | the appropriate type. | |
86 | </DD> | |
87 | <DT><STRONG><code>parser</code></STRONG></DT> | |
88 | <DD>is the OptionParser instance driving the whole thing, mainly | |
89 | useful because you can access some other interesting data through | |
90 | its instance attributes: | |
91 | <DL> | |
92 | <DT><STRONG><code>parser.largs</code></STRONG></DT> | |
93 | <DD>the current list of leftover arguments, ie. arguments that have | |
94 | been consumed but are neither options nor option arguments. | |
95 | Feel free to modify <code>parser.largs</code>, e.g. by adding more | |
96 | arguments to it. (This list will become <code>args</code>, the second | |
97 | return value of <tt class="method">parse_args()</tt>.) | |
98 | </DD> | |
99 | <DT><STRONG><code>parser.rargs</code></STRONG></DT> | |
100 | <DD>the current list of remaining arguments, ie. with <code>opt_str</code> and | |
101 | <code>value</code> (if applicable) removed, and only the arguments | |
102 | following them still there. Feel free to modify | |
103 | <code>parser.rargs</code>, e.g. by consuming more arguments. | |
104 | </DD> | |
105 | <DT><STRONG><code>parser.values</code></STRONG></DT> | |
106 | <DD>the object where option values are by default stored (an | |
107 | instance of optparse.OptionValues). This lets callbacks use the | |
108 | same mechanism as the rest of <tt class="module">optparse</tt> for storing option values; | |
109 | you don't need to mess around with globals or closures. You can | |
110 | also access or modify the value(s) of any options already | |
111 | encountered on the command-line. | |
112 | </DD> | |
113 | </DL> | |
114 | </DD> | |
115 | <DT><STRONG><code>args</code></STRONG></DT> | |
116 | <DD>is a tuple of arbitrary positional arguments supplied via the | |
117 | <code>callback_args</code> option attribute. | |
118 | </DD> | |
119 | <DT><STRONG><code>kwargs</code></STRONG></DT> | |
120 | <DD>is a dictionary of arbitrary keyword arguments supplied via | |
121 | <code>callback_kwargs</code>. | |
122 | </DD> | |
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