-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathcmd.html
More file actions
544 lines (489 loc) · 43.1 KB
/
cmd.html
File metadata and controls
544 lines (489 loc) · 43.1 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="zh_TW">
<head>
<meta http-equiv="X-UA-Compatible" content="IE=Edge" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>25.2. cmd — Support for line-oriented command interpreters — Python 3.7.0 說明文件</title>
<link rel="stylesheet" href="../_static/pydoctheme.css" type="text/css" />
<link rel="stylesheet" href="../_static/pygments.css" type="text/css" />
<script type="text/javascript" id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script>
<script type="text/javascript" src="../_static/jquery.js"></script>
<script type="text/javascript" src="../_static/underscore.js"></script>
<script type="text/javascript" src="../_static/doctools.js"></script>
<script type="text/javascript" src="../_static/translations.js"></script>
<script type="text/javascript" src="../_static/sidebar.js"></script>
<link rel="search" type="application/opensearchdescription+xml"
title="在 Python 3.7.0 說明文件 中搜尋"
href="../_static/opensearch.xml"/>
<link rel="author" title="關於這些文件" href="../about.html" />
<link rel="index" title="索引" href="../genindex.html" />
<link rel="search" title="搜尋" href="../search.html" />
<link rel="copyright" title="Copyright" href="../copyright.html" />
<link rel="next" title="25.3. shlex — Simple lexical analysis" href="shlex.html" />
<link rel="prev" title="25.1. turtle — 龜圖學" href="turtle.html" />
<link rel="shortcut icon" type="image/png" href="../_static/py.png" />
<link rel="canonical" href="https://docs.python.org/3/library/cmd.html" />
<script type="text/javascript" src="../_static/copybutton.js"></script>
<script type="text/javascript" src="../_static/switchers.js"></script>
</head><body>
<div class="related" role="navigation" aria-label="related navigation">
<h3>瀏覽</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="../genindex.html" title="General Index"
accesskey="I">索引</a></li>
<li class="right" >
<a href="../py-modindex.html" title="Python 模組索引"
>模組</a> |</li>
<li class="right" >
<a href="shlex.html" title="25.3. shlex — Simple lexical analysis"
accesskey="N">下一頁</a> |</li>
<li class="right" >
<a href="turtle.html" title="25.1. turtle — 龜圖學"
accesskey="P">上一頁</a> |</li>
<li><img src="../_static/py.png" alt=""
style="vertical-align: middle; margin-top: -1px"/></li>
<li><a href="https://www.python.org/">Python</a> »</li>
<li>
<span class="language_switcher_placeholder">zh_TW</span>
<span class="version_switcher_placeholder">3.7.0</span>
<a href="../index.html">Documentation </a> »
</li>
<li class="nav-item nav-item-1"><a href="index.html" >Python 標準函式庫 (Standard Library)</a> »</li>
<li class="nav-item nav-item-2"><a href="frameworks.html" accesskey="U">25. 程式框架</a> »</li>
<li class="right">
<div class="inline-search" style="display: none" role="search">
<form class="inline-search" action="../search.html" method="get">
<input placeholder="Quick search" type="text" name="q" />
<input type="submit" value="Go" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
</div>
<script type="text/javascript">$('.inline-search').show(0);</script>
|
</li>
</ul>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body" role="main">
<div class="section" id="module-cmd">
<span id="cmd-support-for-line-oriented-command-interpreters"></span><h1>25.2. <a class="reference internal" href="#module-cmd" title="cmd: Build line-oriented command interpreters."><code class="xref py py-mod docutils literal notranslate"><span class="pre">cmd</span></code></a> — Support for line-oriented command interpreters<a class="headerlink" href="#module-cmd" title="本標題的永久連結">¶</a></h1>
<p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.7/Lib/cmd.py">Lib/cmd.py</a></p>
<hr class="docutils" />
<p>The <a class="reference internal" href="#cmd.Cmd" title="cmd.Cmd"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cmd</span></code></a> class provides a simple framework for writing line-oriented
command interpreters. These are often useful for test harnesses, administrative
tools, and prototypes that will later be wrapped in a more sophisticated
interface.</p>
<dl class="class">
<dt id="cmd.Cmd">
<em class="property">class </em><code class="descclassname">cmd.</code><code class="descname">Cmd</code><span class="sig-paren">(</span><em>completekey='tab'</em>, <em>stdin=None</em>, <em>stdout=None</em><span class="sig-paren">)</span><a class="headerlink" href="#cmd.Cmd" title="本定義的永久連結">¶</a></dt>
<dd><p>A <a class="reference internal" href="#cmd.Cmd" title="cmd.Cmd"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cmd</span></code></a> instance or subclass instance is a line-oriented interpreter
framework. There is no good reason to instantiate <a class="reference internal" href="#cmd.Cmd" title="cmd.Cmd"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cmd</span></code></a> itself; rather,
it’s useful as a superclass of an interpreter class you define yourself in order
to inherit <a class="reference internal" href="#cmd.Cmd" title="cmd.Cmd"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cmd</span></code></a>’s methods and encapsulate action methods.</p>
<p>The optional argument <em>completekey</em> is the <a class="reference internal" href="readline.html#module-readline" title="readline: GNU readline support for Python. (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">readline</span></code></a> name of a completion
key; it defaults to <kbd class="kbd docutils literal notranslate">Tab</kbd>. If <em>completekey</em> is not <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a> and
<a class="reference internal" href="readline.html#module-readline" title="readline: GNU readline support for Python. (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">readline</span></code></a> is available, command completion is done automatically.</p>
<p>The optional arguments <em>stdin</em> and <em>stdout</em> specify the input and output file
objects that the Cmd instance or subclass instance will use for input and
output. If not specified, they will default to <a class="reference internal" href="sys.html#sys.stdin" title="sys.stdin"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.stdin</span></code></a> and
<a class="reference internal" href="sys.html#sys.stdout" title="sys.stdout"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.stdout</span></code></a>.</p>
<p>If you want a given <em>stdin</em> to be used, make sure to set the instance’s
<a class="reference internal" href="#cmd.Cmd.use_rawinput" title="cmd.Cmd.use_rawinput"><code class="xref py py-attr docutils literal notranslate"><span class="pre">use_rawinput</span></code></a> attribute to <code class="docutils literal notranslate"><span class="pre">False</span></code>, otherwise <em>stdin</em> will be
ignored.</p>
</dd></dl>
<div class="section" id="cmd-objects">
<span id="id1"></span><h2>25.2.1. Cmd Objects<a class="headerlink" href="#cmd-objects" title="本標題的永久連結">¶</a></h2>
<p>A <a class="reference internal" href="#cmd.Cmd" title="cmd.Cmd"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cmd</span></code></a> instance has the following methods:</p>
<dl class="method">
<dt id="cmd.Cmd.cmdloop">
<code class="descclassname">Cmd.</code><code class="descname">cmdloop</code><span class="sig-paren">(</span><em>intro=None</em><span class="sig-paren">)</span><a class="headerlink" href="#cmd.Cmd.cmdloop" title="本定義的永久連結">¶</a></dt>
<dd><p>Repeatedly issue a prompt, accept input, parse an initial prefix off the
received input, and dispatch to action methods, passing them the remainder of
the line as argument.</p>
<p>The optional argument is a banner or intro string to be issued before the first
prompt (this overrides the <a class="reference internal" href="#cmd.Cmd.intro" title="cmd.Cmd.intro"><code class="xref py py-attr docutils literal notranslate"><span class="pre">intro</span></code></a> class attribute).</p>
<p>If the <a class="reference internal" href="readline.html#module-readline" title="readline: GNU readline support for Python. (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">readline</span></code></a> module is loaded, input will automatically inherit
<strong class="program">bash</strong>-like history-list editing (e.g. <kbd class="kbd docutils literal notranslate">Control-P</kbd> scrolls back
to the last command, <kbd class="kbd docutils literal notranslate">Control-N</kbd> forward to the next one, <kbd class="kbd docutils literal notranslate">Control-F</kbd>
moves the cursor to the right non-destructively, <kbd class="kbd docutils literal notranslate">Control-B</kbd> moves the
cursor to the left non-destructively, etc.).</p>
<p>An end-of-file on input is passed back as the string <code class="docutils literal notranslate"><span class="pre">'EOF'</span></code>.</p>
<p>An interpreter instance will recognize a command name <code class="docutils literal notranslate"><span class="pre">foo</span></code> if and only if it
has a method <code class="xref py py-meth docutils literal notranslate"><span class="pre">do_foo()</span></code>. As a special case, a line beginning with the
character <code class="docutils literal notranslate"><span class="pre">'?'</span></code> is dispatched to the method <code class="xref py py-meth docutils literal notranslate"><span class="pre">do_help()</span></code>. As another
special case, a line beginning with the character <code class="docutils literal notranslate"><span class="pre">'!'</span></code> is dispatched to the
method <code class="xref py py-meth docutils literal notranslate"><span class="pre">do_shell()</span></code> (if such a method is defined).</p>
<p>This method will return when the <a class="reference internal" href="#cmd.Cmd.postcmd" title="cmd.Cmd.postcmd"><code class="xref py py-meth docutils literal notranslate"><span class="pre">postcmd()</span></code></a> method returns a true value.
The <em>stop</em> argument to <a class="reference internal" href="#cmd.Cmd.postcmd" title="cmd.Cmd.postcmd"><code class="xref py py-meth docutils literal notranslate"><span class="pre">postcmd()</span></code></a> is the return value from the command’s
corresponding <code class="xref py py-meth docutils literal notranslate"><span class="pre">do_*()</span></code> method.</p>
<p>If completion is enabled, completing commands will be done automatically, and
completing of commands args is done by calling <code class="xref py py-meth docutils literal notranslate"><span class="pre">complete_foo()</span></code> with
arguments <em>text</em>, <em>line</em>, <em>begidx</em>, and <em>endidx</em>. <em>text</em> is the string prefix
we are attempting to match: all returned matches must begin with it. <em>line</em> is
the current input line with leading whitespace removed, <em>begidx</em> and <em>endidx</em>
are the beginning and ending indexes of the prefix text, which could be used to
provide different completion depending upon which position the argument is in.</p>
<p>All subclasses of <a class="reference internal" href="#cmd.Cmd" title="cmd.Cmd"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cmd</span></code></a> inherit a predefined <code class="xref py py-meth docutils literal notranslate"><span class="pre">do_help()</span></code>. This
method, called with an argument <code class="docutils literal notranslate"><span class="pre">'bar'</span></code>, invokes the corresponding method
<code class="xref py py-meth docutils literal notranslate"><span class="pre">help_bar()</span></code>, and if that is not present, prints the docstring of
<code class="xref py py-meth docutils literal notranslate"><span class="pre">do_bar()</span></code>, if available. With no argument, <code class="xref py py-meth docutils literal notranslate"><span class="pre">do_help()</span></code> lists all
available help topics (that is, all commands with corresponding
<code class="xref py py-meth docutils literal notranslate"><span class="pre">help_*()</span></code> methods or commands that have docstrings), and also lists any
undocumented commands.</p>
</dd></dl>
<dl class="method">
<dt id="cmd.Cmd.onecmd">
<code class="descclassname">Cmd.</code><code class="descname">onecmd</code><span class="sig-paren">(</span><em>str</em><span class="sig-paren">)</span><a class="headerlink" href="#cmd.Cmd.onecmd" title="本定義的永久連結">¶</a></dt>
<dd><p>Interpret the argument as though it had been typed in response to the prompt.
This may be overridden, but should not normally need to be; see the
<a class="reference internal" href="#cmd.Cmd.precmd" title="cmd.Cmd.precmd"><code class="xref py py-meth docutils literal notranslate"><span class="pre">precmd()</span></code></a> and <a class="reference internal" href="#cmd.Cmd.postcmd" title="cmd.Cmd.postcmd"><code class="xref py py-meth docutils literal notranslate"><span class="pre">postcmd()</span></code></a> methods for useful execution hooks. The
return value is a flag indicating whether interpretation of commands by the
interpreter should stop. If there is a <code class="xref py py-meth docutils literal notranslate"><span class="pre">do_*()</span></code> method for the command
<em>str</em>, the return value of that method is returned, otherwise the return value
from the <a class="reference internal" href="#cmd.Cmd.default" title="cmd.Cmd.default"><code class="xref py py-meth docutils literal notranslate"><span class="pre">default()</span></code></a> method is returned.</p>
</dd></dl>
<dl class="method">
<dt id="cmd.Cmd.emptyline">
<code class="descclassname">Cmd.</code><code class="descname">emptyline</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#cmd.Cmd.emptyline" title="本定義的永久連結">¶</a></dt>
<dd><p>Method called when an empty line is entered in response to the prompt. If this
method is not overridden, it repeats the last nonempty command entered.</p>
</dd></dl>
<dl class="method">
<dt id="cmd.Cmd.default">
<code class="descclassname">Cmd.</code><code class="descname">default</code><span class="sig-paren">(</span><em>line</em><span class="sig-paren">)</span><a class="headerlink" href="#cmd.Cmd.default" title="本定義的永久連結">¶</a></dt>
<dd><p>Method called on an input line when the command prefix is not recognized. If
this method is not overridden, it prints an error message and returns.</p>
</dd></dl>
<dl class="method">
<dt id="cmd.Cmd.completedefault">
<code class="descclassname">Cmd.</code><code class="descname">completedefault</code><span class="sig-paren">(</span><em>text</em>, <em>line</em>, <em>begidx</em>, <em>endidx</em><span class="sig-paren">)</span><a class="headerlink" href="#cmd.Cmd.completedefault" title="本定義的永久連結">¶</a></dt>
<dd><p>Method called to complete an input line when no command-specific
<code class="xref py py-meth docutils literal notranslate"><span class="pre">complete_*()</span></code> method is available. By default, it returns an empty list.</p>
</dd></dl>
<dl class="method">
<dt id="cmd.Cmd.precmd">
<code class="descclassname">Cmd.</code><code class="descname">precmd</code><span class="sig-paren">(</span><em>line</em><span class="sig-paren">)</span><a class="headerlink" href="#cmd.Cmd.precmd" title="本定義的永久連結">¶</a></dt>
<dd><p>Hook method executed just before the command line <em>line</em> is interpreted, but
after the input prompt is generated and issued. This method is a stub in
<a class="reference internal" href="#cmd.Cmd" title="cmd.Cmd"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cmd</span></code></a>; it exists to be overridden by subclasses. The return value is
used as the command which will be executed by the <a class="reference internal" href="#cmd.Cmd.onecmd" title="cmd.Cmd.onecmd"><code class="xref py py-meth docutils literal notranslate"><span class="pre">onecmd()</span></code></a> method; the
<a class="reference internal" href="#cmd.Cmd.precmd" title="cmd.Cmd.precmd"><code class="xref py py-meth docutils literal notranslate"><span class="pre">precmd()</span></code></a> implementation may re-write the command or simply return <em>line</em>
unchanged.</p>
</dd></dl>
<dl class="method">
<dt id="cmd.Cmd.postcmd">
<code class="descclassname">Cmd.</code><code class="descname">postcmd</code><span class="sig-paren">(</span><em>stop</em>, <em>line</em><span class="sig-paren">)</span><a class="headerlink" href="#cmd.Cmd.postcmd" title="本定義的永久連結">¶</a></dt>
<dd><p>Hook method executed just after a command dispatch is finished. This method is
a stub in <a class="reference internal" href="#cmd.Cmd" title="cmd.Cmd"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cmd</span></code></a>; it exists to be overridden by subclasses. <em>line</em> is the
command line which was executed, and <em>stop</em> is a flag which indicates whether
execution will be terminated after the call to <a class="reference internal" href="#cmd.Cmd.postcmd" title="cmd.Cmd.postcmd"><code class="xref py py-meth docutils literal notranslate"><span class="pre">postcmd()</span></code></a>; this will be the
return value of the <a class="reference internal" href="#cmd.Cmd.onecmd" title="cmd.Cmd.onecmd"><code class="xref py py-meth docutils literal notranslate"><span class="pre">onecmd()</span></code></a> method. The return value of this method will
be used as the new value for the internal flag which corresponds to <em>stop</em>;
returning false will cause interpretation to continue.</p>
</dd></dl>
<dl class="method">
<dt id="cmd.Cmd.preloop">
<code class="descclassname">Cmd.</code><code class="descname">preloop</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#cmd.Cmd.preloop" title="本定義的永久連結">¶</a></dt>
<dd><p>Hook method executed once when <a class="reference internal" href="#cmd.Cmd.cmdloop" title="cmd.Cmd.cmdloop"><code class="xref py py-meth docutils literal notranslate"><span class="pre">cmdloop()</span></code></a> is called. This method is a stub
in <a class="reference internal" href="#cmd.Cmd" title="cmd.Cmd"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cmd</span></code></a>; it exists to be overridden by subclasses.</p>
</dd></dl>
<dl class="method">
<dt id="cmd.Cmd.postloop">
<code class="descclassname">Cmd.</code><code class="descname">postloop</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#cmd.Cmd.postloop" title="本定義的永久連結">¶</a></dt>
<dd><p>Hook method executed once when <a class="reference internal" href="#cmd.Cmd.cmdloop" title="cmd.Cmd.cmdloop"><code class="xref py py-meth docutils literal notranslate"><span class="pre">cmdloop()</span></code></a> is about to return. This method
is a stub in <a class="reference internal" href="#cmd.Cmd" title="cmd.Cmd"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cmd</span></code></a>; it exists to be overridden by subclasses.</p>
</dd></dl>
<p>Instances of <a class="reference internal" href="#cmd.Cmd" title="cmd.Cmd"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cmd</span></code></a> subclasses have some public instance variables:</p>
<dl class="attribute">
<dt id="cmd.Cmd.prompt">
<code class="descclassname">Cmd.</code><code class="descname">prompt</code><a class="headerlink" href="#cmd.Cmd.prompt" title="本定義的永久連結">¶</a></dt>
<dd><p>The prompt issued to solicit input.</p>
</dd></dl>
<dl class="attribute">
<dt id="cmd.Cmd.identchars">
<code class="descclassname">Cmd.</code><code class="descname">identchars</code><a class="headerlink" href="#cmd.Cmd.identchars" title="本定義的永久連結">¶</a></dt>
<dd><p>The string of characters accepted for the command prefix.</p>
</dd></dl>
<dl class="attribute">
<dt id="cmd.Cmd.lastcmd">
<code class="descclassname">Cmd.</code><code class="descname">lastcmd</code><a class="headerlink" href="#cmd.Cmd.lastcmd" title="本定義的永久連結">¶</a></dt>
<dd><p>The last nonempty command prefix seen.</p>
</dd></dl>
<dl class="attribute">
<dt id="cmd.Cmd.cmdqueue">
<code class="descclassname">Cmd.</code><code class="descname">cmdqueue</code><a class="headerlink" href="#cmd.Cmd.cmdqueue" title="本定義的永久連結">¶</a></dt>
<dd><p>A list of queued input lines. The cmdqueue list is checked in
<a class="reference internal" href="#cmd.Cmd.cmdloop" title="cmd.Cmd.cmdloop"><code class="xref py py-meth docutils literal notranslate"><span class="pre">cmdloop()</span></code></a> when new input is needed; if it is nonempty, its elements
will be processed in order, as if entered at the prompt.</p>
</dd></dl>
<dl class="attribute">
<dt id="cmd.Cmd.intro">
<code class="descclassname">Cmd.</code><code class="descname">intro</code><a class="headerlink" href="#cmd.Cmd.intro" title="本定義的永久連結">¶</a></dt>
<dd><p>A string to issue as an intro or banner. May be overridden by giving the
<a class="reference internal" href="#cmd.Cmd.cmdloop" title="cmd.Cmd.cmdloop"><code class="xref py py-meth docutils literal notranslate"><span class="pre">cmdloop()</span></code></a> method an argument.</p>
</dd></dl>
<dl class="attribute">
<dt id="cmd.Cmd.doc_header">
<code class="descclassname">Cmd.</code><code class="descname">doc_header</code><a class="headerlink" href="#cmd.Cmd.doc_header" title="本定義的永久連結">¶</a></dt>
<dd><p>The header to issue if the help output has a section for documented commands.</p>
</dd></dl>
<dl class="attribute">
<dt id="cmd.Cmd.misc_header">
<code class="descclassname">Cmd.</code><code class="descname">misc_header</code><a class="headerlink" href="#cmd.Cmd.misc_header" title="本定義的永久連結">¶</a></dt>
<dd><p>The header to issue if the help output has a section for miscellaneous help
topics (that is, there are <code class="xref py py-meth docutils literal notranslate"><span class="pre">help_*()</span></code> methods without corresponding
<code class="xref py py-meth docutils literal notranslate"><span class="pre">do_*()</span></code> methods).</p>
</dd></dl>
<dl class="attribute">
<dt id="cmd.Cmd.undoc_header">
<code class="descclassname">Cmd.</code><code class="descname">undoc_header</code><a class="headerlink" href="#cmd.Cmd.undoc_header" title="本定義的永久連結">¶</a></dt>
<dd><p>The header to issue if the help output has a section for undocumented commands
(that is, there are <code class="xref py py-meth docutils literal notranslate"><span class="pre">do_*()</span></code> methods without corresponding <code class="xref py py-meth docutils literal notranslate"><span class="pre">help_*()</span></code>
methods).</p>
</dd></dl>
<dl class="attribute">
<dt id="cmd.Cmd.ruler">
<code class="descclassname">Cmd.</code><code class="descname">ruler</code><a class="headerlink" href="#cmd.Cmd.ruler" title="本定義的永久連結">¶</a></dt>
<dd><p>The character used to draw separator lines under the help-message headers. If
empty, no ruler line is drawn. It defaults to <code class="docutils literal notranslate"><span class="pre">'='</span></code>.</p>
</dd></dl>
<dl class="attribute">
<dt id="cmd.Cmd.use_rawinput">
<code class="descclassname">Cmd.</code><code class="descname">use_rawinput</code><a class="headerlink" href="#cmd.Cmd.use_rawinput" title="本定義的永久連結">¶</a></dt>
<dd><p>A flag, defaulting to true. If true, <a class="reference internal" href="#cmd.Cmd.cmdloop" title="cmd.Cmd.cmdloop"><code class="xref py py-meth docutils literal notranslate"><span class="pre">cmdloop()</span></code></a> uses <a class="reference internal" href="functions.html#input" title="input"><code class="xref py py-func docutils literal notranslate"><span class="pre">input()</span></code></a> to
display a prompt and read the next command; if false, <code class="xref py py-meth docutils literal notranslate"><span class="pre">sys.stdout.write()</span></code>
and <code class="xref py py-meth docutils literal notranslate"><span class="pre">sys.stdin.readline()</span></code> are used. (This means that by importing
<a class="reference internal" href="readline.html#module-readline" title="readline: GNU readline support for Python. (Unix)"><code class="xref py py-mod docutils literal notranslate"><span class="pre">readline</span></code></a>, on systems that support it, the interpreter will automatically
support <strong class="program">Emacs</strong>-like line editing and command-history keystrokes.)</p>
</dd></dl>
</div>
<div class="section" id="cmd-example">
<span id="id2"></span><h2>25.2.2. Cmd Example<a class="headerlink" href="#cmd-example" title="本標題的永久連結">¶</a></h2>
<p>The <a class="reference internal" href="#module-cmd" title="cmd: Build line-oriented command interpreters."><code class="xref py py-mod docutils literal notranslate"><span class="pre">cmd</span></code></a> module is mainly useful for building custom shells that let a
user work with a program interactively.</p>
<p>This section presents a simple example of how to build a shell around a few of
the commands in the <a class="reference internal" href="turtle.html#module-turtle" title="turtle: An educational framework for simple graphics applications"><code class="xref py py-mod docutils literal notranslate"><span class="pre">turtle</span></code></a> module.</p>
<p>Basic turtle commands such as <a class="reference internal" href="turtle.html#turtle.forward" title="turtle.forward"><code class="xref py py-meth docutils literal notranslate"><span class="pre">forward()</span></code></a> are added to a
<a class="reference internal" href="#cmd.Cmd" title="cmd.Cmd"><code class="xref py py-class docutils literal notranslate"><span class="pre">Cmd</span></code></a> subclass with method named <code class="xref py py-meth docutils literal notranslate"><span class="pre">do_forward()</span></code>. The argument is
converted to a number and dispatched to the turtle module. The docstring is
used in the help utility provided by the shell.</p>
<p>The example also includes a basic record and playback facility implemented with
the <a class="reference internal" href="#cmd.Cmd.precmd" title="cmd.Cmd.precmd"><code class="xref py py-meth docutils literal notranslate"><span class="pre">precmd()</span></code></a> method which is responsible for converting the input to
lowercase and writing the commands to a file. The <code class="xref py py-meth docutils literal notranslate"><span class="pre">do_playback()</span></code> method
reads the file and adds the recorded commands to the <code class="xref py py-attr docutils literal notranslate"><span class="pre">cmdqueue</span></code> for
immediate playback:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">cmd</span><span class="o">,</span> <span class="nn">sys</span>
<span class="kn">from</span> <span class="nn">turtle</span> <span class="k">import</span> <span class="o">*</span>
<span class="k">class</span> <span class="nc">TurtleShell</span><span class="p">(</span><span class="n">cmd</span><span class="o">.</span><span class="n">Cmd</span><span class="p">):</span>
<span class="n">intro</span> <span class="o">=</span> <span class="s1">'Welcome to the turtle shell. Type help or ? to list commands.</span><span class="se">\n</span><span class="s1">'</span>
<span class="n">prompt</span> <span class="o">=</span> <span class="s1">'(turtle) '</span>
<span class="n">file</span> <span class="o">=</span> <span class="kc">None</span>
<span class="c1"># ----- basic turtle commands -----</span>
<span class="k">def</span> <span class="nf">do_forward</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">arg</span><span class="p">):</span>
<span class="s1">'Move the turtle forward by the specified distance: FORWARD 10'</span>
<span class="n">forward</span><span class="p">(</span><span class="o">*</span><span class="n">parse</span><span class="p">(</span><span class="n">arg</span><span class="p">))</span>
<span class="k">def</span> <span class="nf">do_right</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">arg</span><span class="p">):</span>
<span class="s1">'Turn turtle right by given number of degrees: RIGHT 20'</span>
<span class="n">right</span><span class="p">(</span><span class="o">*</span><span class="n">parse</span><span class="p">(</span><span class="n">arg</span><span class="p">))</span>
<span class="k">def</span> <span class="nf">do_left</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">arg</span><span class="p">):</span>
<span class="s1">'Turn turtle left by given number of degrees: LEFT 90'</span>
<span class="n">left</span><span class="p">(</span><span class="o">*</span><span class="n">parse</span><span class="p">(</span><span class="n">arg</span><span class="p">))</span>
<span class="k">def</span> <span class="nf">do_goto</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">arg</span><span class="p">):</span>
<span class="s1">'Move turtle to an absolute position with changing orientation. GOTO 100 200'</span>
<span class="n">goto</span><span class="p">(</span><span class="o">*</span><span class="n">parse</span><span class="p">(</span><span class="n">arg</span><span class="p">))</span>
<span class="k">def</span> <span class="nf">do_home</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">arg</span><span class="p">):</span>
<span class="s1">'Return turtle to the home position: HOME'</span>
<span class="n">home</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">do_circle</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">arg</span><span class="p">):</span>
<span class="s1">'Draw circle with given radius an options extent and steps: CIRCLE 50'</span>
<span class="n">circle</span><span class="p">(</span><span class="o">*</span><span class="n">parse</span><span class="p">(</span><span class="n">arg</span><span class="p">))</span>
<span class="k">def</span> <span class="nf">do_position</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">arg</span><span class="p">):</span>
<span class="s1">'Print the current turtle position: POSITION'</span>
<span class="nb">print</span><span class="p">(</span><span class="s1">'Current position is </span><span class="si">%d</span><span class="s1"> </span><span class="si">%d</span><span class="se">\n</span><span class="s1">'</span> <span class="o">%</span> <span class="n">position</span><span class="p">())</span>
<span class="k">def</span> <span class="nf">do_heading</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">arg</span><span class="p">):</span>
<span class="s1">'Print the current turtle heading in degrees: HEADING'</span>
<span class="nb">print</span><span class="p">(</span><span class="s1">'Current heading is </span><span class="si">%d</span><span class="se">\n</span><span class="s1">'</span> <span class="o">%</span> <span class="p">(</span><span class="n">heading</span><span class="p">(),))</span>
<span class="k">def</span> <span class="nf">do_color</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">arg</span><span class="p">):</span>
<span class="s1">'Set the color: COLOR BLUE'</span>
<span class="n">color</span><span class="p">(</span><span class="n">arg</span><span class="o">.</span><span class="n">lower</span><span class="p">())</span>
<span class="k">def</span> <span class="nf">do_undo</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">arg</span><span class="p">):</span>
<span class="s1">'Undo (repeatedly) the last turtle action(s): UNDO'</span>
<span class="k">def</span> <span class="nf">do_reset</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">arg</span><span class="p">):</span>
<span class="s1">'Clear the screen and return turtle to center: RESET'</span>
<span class="n">reset</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">do_bye</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">arg</span><span class="p">):</span>
<span class="s1">'Stop recording, close the turtle window, and exit: BYE'</span>
<span class="nb">print</span><span class="p">(</span><span class="s1">'Thank you for using Turtle'</span><span class="p">)</span>
<span class="bp">self</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
<span class="n">bye</span><span class="p">()</span>
<span class="k">return</span> <span class="kc">True</span>
<span class="c1"># ----- record and playback -----</span>
<span class="k">def</span> <span class="nf">do_record</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">arg</span><span class="p">):</span>
<span class="s1">'Save future commands to filename: RECORD rose.cmd'</span>
<span class="bp">self</span><span class="o">.</span><span class="n">file</span> <span class="o">=</span> <span class="nb">open</span><span class="p">(</span><span class="n">arg</span><span class="p">,</span> <span class="s1">'w'</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">do_playback</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">arg</span><span class="p">):</span>
<span class="s1">'Playback commands from a file: PLAYBACK rose.cmd'</span>
<span class="bp">self</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
<span class="k">with</span> <span class="nb">open</span><span class="p">(</span><span class="n">arg</span><span class="p">)</span> <span class="k">as</span> <span class="n">f</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">cmdqueue</span><span class="o">.</span><span class="n">extend</span><span class="p">(</span><span class="n">f</span><span class="o">.</span><span class="n">read</span><span class="p">()</span><span class="o">.</span><span class="n">splitlines</span><span class="p">())</span>
<span class="k">def</span> <span class="nf">precmd</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">line</span><span class="p">):</span>
<span class="n">line</span> <span class="o">=</span> <span class="n">line</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span>
<span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">file</span> <span class="ow">and</span> <span class="s1">'playback'</span> <span class="ow">not</span> <span class="ow">in</span> <span class="n">line</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="n">line</span><span class="p">,</span> <span class="n">file</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">file</span><span class="p">)</span>
<span class="k">return</span> <span class="n">line</span>
<span class="k">def</span> <span class="nf">close</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">file</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">file</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
<span class="bp">self</span><span class="o">.</span><span class="n">file</span> <span class="o">=</span> <span class="kc">None</span>
<span class="k">def</span> <span class="nf">parse</span><span class="p">(</span><span class="n">arg</span><span class="p">):</span>
<span class="s1">'Convert a series of zero or more numbers to an argument tuple'</span>
<span class="k">return</span> <span class="nb">tuple</span><span class="p">(</span><span class="nb">map</span><span class="p">(</span><span class="nb">int</span><span class="p">,</span> <span class="n">arg</span><span class="o">.</span><span class="n">split</span><span class="p">()))</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s1">'__main__'</span><span class="p">:</span>
<span class="n">TurtleShell</span><span class="p">()</span><span class="o">.</span><span class="n">cmdloop</span><span class="p">()</span>
</pre></div>
</div>
<p>Here is a sample session with the turtle shell showing the help functions, using
blank lines to repeat commands, and the simple record and playback facility:</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>Welcome to the turtle shell. Type help or ? to list commands.
(turtle) ?
Documented commands (type help <topic>):
========================================
bye color goto home playback record right
circle forward heading left position reset undo
(turtle) help forward
Move the turtle forward by the specified distance: FORWARD 10
(turtle) record spiral.cmd
(turtle) position
Current position is 0 0
(turtle) heading
Current heading is 0
(turtle) reset
(turtle) circle 20
(turtle) right 30
(turtle) circle 40
(turtle) right 30
(turtle) circle 60
(turtle) right 30
(turtle) circle 80
(turtle) right 30
(turtle) circle 100
(turtle) right 30
(turtle) circle 120
(turtle) right 30
(turtle) circle 120
(turtle) heading
Current heading is 180
(turtle) forward 100
(turtle)
(turtle) right 90
(turtle) forward 100
(turtle)
(turtle) right 90
(turtle) forward 400
(turtle) right 90
(turtle) forward 500
(turtle) right 90
(turtle) forward 400
(turtle) right 90
(turtle) forward 300
(turtle) playback spiral.cmd
Current position is 0 0
Current heading is 0
Current heading is 180
(turtle) bye
Thank you for using Turtle
</pre></div>
</div>
</div>
</div>
</div>
</div>
</div>
<div class="sphinxsidebar" role="navigation" aria-label="main navigation">
<div class="sphinxsidebarwrapper">
<h3><a href="../contents.html">目錄</a></h3>
<ul>
<li><a class="reference internal" href="#">25.2. <code class="docutils literal notranslate"><span class="pre">cmd</span></code> — Support for line-oriented command interpreters</a><ul>
<li><a class="reference internal" href="#cmd-objects">25.2.1. Cmd Objects</a></li>
<li><a class="reference internal" href="#cmd-example">25.2.2. Cmd Example</a></li>
</ul>
</li>
</ul>
<h4>上個主題</h4>
<p class="topless"><a href="turtle.html"
title="上一章">25.1. <code class="docutils literal notranslate"><span class="pre">turtle</span></code> — 龜圖學</a></p>
<h4>下個主題</h4>
<p class="topless"><a href="shlex.html"
title="下一章">25.3. <code class="docutils literal notranslate"><span class="pre">shlex</span></code> — Simple lexical analysis</a></p>
<div role="note" aria-label="source link">
<h3>This Page</h3>
<ul class="this-page-menu">
<li><a href="../bugs.html">Report a Bug</a></li>
<li>
<a href="https://github.com/python/cpython/blob/3.7/Doc/library/cmd.rst"
rel="nofollow">Show Source
</a>
</li>
</ul>
</div>
</div>
</div>
<div class="clearer"></div>
</div>
<div class="related" role="navigation" aria-label="related navigation">
<h3>瀏覽</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="../genindex.html" title="General Index"
>索引</a></li>
<li class="right" >
<a href="../py-modindex.html" title="Python 模組索引"
>模組</a> |</li>
<li class="right" >
<a href="shlex.html" title="25.3. shlex — Simple lexical analysis"
>下一頁</a> |</li>
<li class="right" >
<a href="turtle.html" title="25.1. turtle — 龜圖學"
>上一頁</a> |</li>
<li><img src="../_static/py.png" alt=""
style="vertical-align: middle; margin-top: -1px"/></li>
<li><a href="https://www.python.org/">Python</a> »</li>
<li>
<span class="language_switcher_placeholder">zh_TW</span>
<span class="version_switcher_placeholder">3.7.0</span>
<a href="../index.html">Documentation </a> »
</li>
<li class="nav-item nav-item-1"><a href="index.html" >Python 標準函式庫 (Standard Library)</a> »</li>
<li class="nav-item nav-item-2"><a href="frameworks.html" >25. 程式框架</a> »</li>
<li class="right">
<div class="inline-search" style="display: none" role="search">
<form class="inline-search" action="../search.html" method="get">
<input placeholder="Quick search" type="text" name="q" />
<input type="submit" value="Go" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
</div>
<script type="text/javascript">$('.inline-search').show(0);</script>
|
</li>
</ul>
</div>
<div class="footer">
© <a href="../copyright.html">Copyright</a> 2001-2018, Python Software Foundation.
<br />
The Python Software Foundation is a non-profit corporation.
<a href="https://www.python.org/psf/donations/">Please donate.</a>
<br />
Last updated on 8月 22, 2018.
<a href="../bugs.html">Found a bug</a>?
<br />
Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.7.7.
</div>
</body>
</html>