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| 52 | |
| 53 | <H2><A NAME="SECTION000730000000000000000"></A><A NAME="info-units"></A> |
| 54 | <BR> |
| 55 | 6.3 Information Units |
| 56 | </H2> |
| 57 | |
| 58 | <P> |
| 59 | XXX Explain terminology, or come up with something more ``lay.'' |
| 60 | |
| 61 | <P> |
| 62 | There are a number of environments used to describe specific |
| 63 | features provided by modules. Each environment requires |
| 64 | parameters needed to provide basic information about what is being |
| 65 | described, and the environment content should be the description. |
| 66 | Most of these environments make entries in the general index (if |
| 67 | one is being produced for the document); if no index entry is |
| 68 | desired, non-indexing variants are available for many of these |
| 69 | environments. The environments have names of the form |
| 70 | <code><var>feature</var>desc</code>, and the non-indexing variants are named |
| 71 | <code><var>feature</var>descni</code>. The available variants are explicitly |
| 72 | included in the list below. |
| 73 | |
| 74 | <P> |
| 75 | For each of these environments, the first parameter, <var>name</var>, |
| 76 | provides the name by which the feature is accessed. |
| 77 | |
| 78 | <P> |
| 79 | Environments which describe features of objects within a module, |
| 80 | such as object methods or data attributes, allow an optional |
| 81 | <var>type name</var> parameter. When the feature is an attribute of |
| 82 | class instances, <var>type name</var> only needs to be given if the |
| 83 | class was not the most recently described class in the module; the |
| 84 | <var>name</var> value from the most recent <tt class='environment'>\classdesc</tt> is implied. |
| 85 | For features of built-in or extension types, the <var>type name</var> |
| 86 | value should always be provided. Another special case includes |
| 87 | methods and members of general ``protocols,'' such as the |
| 88 | formatter and writer protocols described for the |
| 89 | <tt class="module">formatter</tt> module: these may be documented without any |
| 90 | specific implementation classes, and will always require the |
| 91 | <var>type name</var> parameter to be provided. |
| 92 | |
| 93 | <P> |
| 94 | |
| 95 | <dl class='envdesc'> |
| 96 | <dt><tt>\begin{<b class='environment'>cfuncdesc</b>}</tt> |
| 97 | <tt>{</tt><var>type</var><tt>}</tt><tt>{</tt><var>name</var><tt>}</tt><tt>{</tt><var>args</var><tt>}</tt> |
| 98 | <br /><tt>\end{<b class='environment'>cfuncdesc</b>}</tt></dt> |
| 99 | <dd> |
| 100 | Environment used to described a C function. The <var>type</var> |
| 101 | should be specified as a <tt class="keyword">typedef</tt> name, <code>struct |
| 102 | <var>tag</var></code>, or the name of a primitive type. If it is a pointer |
| 103 | type, the trailing asterisk should not be preceded by a space. |
| 104 | <var>name</var> should be the name of the function (or function-like |
| 105 | pre-processor macro), and <var>args</var> should give the types and |
| 106 | names of the parameters. The names need to be given so they may |
| 107 | be used in the description. |
| 108 | </dd></dl> |
| 109 | |
| 110 | <P> |
| 111 | |
| 112 | <dl class='envdesc'> |
| 113 | <dt><tt>\begin{<b class='environment'>cmemberdesc</b>}</tt> |
| 114 | <tt>{</tt><var>container</var><tt>}</tt><tt>{</tt><var>type</var><tt>}</tt><tt>{</tt><var>name</var><tt>}</tt> |
| 115 | <br /><tt>\end{<b class='environment'>cmemberdesc</b>}</tt></dt> |
| 116 | <dd> |
| 117 | Description for a structure member. <var>container</var> should be |
| 118 | the <tt class="keyword">typedef</tt> name, if there is one, otherwise if should |
| 119 | be "<tt class="samp">struct <var>tag</var></tt>". The type of the member should given |
| 120 | as <var>type</var>, and the name should be given as <var>name</var>. The |
| 121 | text of the description should include the range of values |
| 122 | allowed, how the value should be interpreted, and whether the |
| 123 | value can be changed. References to structure members in text |
| 124 | should use the <tt class='macro'>\member</tt> macro. |
| 125 | </dd></dl> |
| 126 | |
| 127 | <P> |
| 128 | |
| 129 | <dl class='envdesc'> |
| 130 | <dt><tt>\begin{<b class='environment'>csimplemacrodesc</b>}</tt> |
| 131 | <tt>{</tt><var>name</var><tt>}</tt> |
| 132 | <br /><tt>\end{<b class='environment'>csimplemacrodesc</b>}</tt></dt> |
| 133 | <dd> |
| 134 | Documentation for a ``simple'' macro. Simple macros are macros |
| 135 | which are used for code expansion, but which do not take |
| 136 | arguments so cannot be described as functions. This is not to |
| 137 | be used for simple constant definitions. Examples of it's use |
| 138 | in the Python documentation include |
| 139 | PyObject_HEAD and |
| 140 | Py_BEGIN_ALLOW_THREADS. |
| 141 | </dd></dl> |
| 142 | |
| 143 | <P> |
| 144 | |
| 145 | <dl class='envdesc'> |
| 146 | <dt><tt>\begin{<b class='environment'>ctypedesc</b>}</tt> |
| 147 | <tt>[</tt><var>tag</var><tt>]</tt><tt>{</tt><var>name</var><tt>}</tt> |
| 148 | <br /><tt>\end{<b class='environment'>ctypedesc</b>}</tt></dt> |
| 149 | <dd> |
| 150 | Environment used to described a C type. The <var>name</var> |
| 151 | parameter should be the <tt class="keyword">typedef</tt> name. If the type is |
| 152 | defined as a <tt class="keyword">struct</tt> without a <tt class="keyword">typedef</tt>, |
| 153 | <var>name</var> should have the form <code>struct <var>tag</var></code>. |
| 154 | <var>name</var> will be added to the index unless <var>tag</var> is |
| 155 | provided, in which case <var>tag</var> will be used instead. |
| 156 | <var>tag</var> should not be used for a <tt class="keyword">typedef</tt> name. |
| 157 | </dd></dl> |
| 158 | |
| 159 | <P> |
| 160 | |
| 161 | <dl class='envdesc'> |
| 162 | <dt><tt>\begin{<b class='environment'>cvardesc</b>}</tt> |
| 163 | <tt>{</tt><var>type</var><tt>}</tt><tt>{</tt><var>name</var><tt>}</tt> |
| 164 | <br /><tt>\end{<b class='environment'>cvardesc</b>}</tt></dt> |
| 165 | <dd> |
| 166 | Description of a global C variable. <var>type</var> should be the |
| 167 | <tt class="keyword">typedef</tt> name, <code>struct <var>tag</var></code>, or the name of |
| 168 | a primitive type. If variable has a pointer type, the trailing |
| 169 | asterisk should <em>not</em> be preceded by a space. |
| 170 | </dd></dl> |
| 171 | |
| 172 | <P> |
| 173 | |
| 174 | <dl class='envdesc'> |
| 175 | <dt><tt>\begin{<b class='environment'>datadesc</b>}</tt> |
| 176 | <tt>{</tt><var>name</var><tt>}</tt> |
| 177 | <br /><tt>\end{<b class='environment'>datadesc</b>}</tt></dt> |
| 178 | <dd> |
| 179 | This environment is used to document global data in a module, |
| 180 | including both variables and values used as ``defined |
| 181 | constants.'' Class and object attributes are not documented |
| 182 | using this environment. |
| 183 | </dd></dl> |
| 184 | |
| 185 | <dl class='envdesc'> |
| 186 | <dt><tt>\begin{<b class='environment'>datadescni</b>}</tt> |
| 187 | <tt>{</tt><var>name</var><tt>}</tt> |
| 188 | <br /><tt>\end{<b class='environment'>datadescni</b>}</tt></dt> |
| 189 | <dd> |
| 190 | Like <tt class='environment'>\datadesc</tt>, but without creating any index entries. |
| 191 | </dd></dl> |
| 192 | |
| 193 | <P> |
| 194 | |
| 195 | <dl class='envdesc'> |
| 196 | <dt><tt>\begin{<b class='environment'>excclassdesc</b>}</tt> |
| 197 | <tt>{</tt><var>name</var><tt>}</tt><tt>{</tt><var>constructor parameters</var><tt>}</tt> |
| 198 | <br /><tt>\end{<b class='environment'>excclassdesc</b>}</tt></dt> |
| 199 | <dd> |
| 200 | Describe an exception defined by a class. <var>constructor |
| 201 | parameters</var> should not include the <var>self</var> parameter or |
| 202 | the parentheses used in the call syntax. To describe an |
| 203 | exception class without describing the parameters to its |
| 204 | constructor, use the <tt class='environment'>\excdesc</tt> environment. |
| 205 | </dd></dl> |
| 206 | |
| 207 | <P> |
| 208 | |
| 209 | <dl class='envdesc'> |
| 210 | <dt><tt>\begin{<b class='environment'>excdesc</b>}</tt> |
| 211 | <tt>{</tt><var>name</var><tt>}</tt> |
| 212 | <br /><tt>\end{<b class='environment'>excdesc</b>}</tt></dt> |
| 213 | <dd> |
| 214 | Describe an exception. In the case of class exceptions, the |
| 215 | constructor parameters are not described; use <tt class='environment'>\excclassdesc</tt> |
| 216 | to describe an exception class and its constructor. |
| 217 | </dd></dl> |
| 218 | |
| 219 | <P> |
| 220 | |
| 221 | <dl class='envdesc'> |
| 222 | <dt><tt>\begin{<b class='environment'>funcdesc</b>}</tt> |
| 223 | <tt>{</tt><var>name</var><tt>}</tt><tt>{</tt><var>parameters</var><tt>}</tt> |
| 224 | <br /><tt>\end{<b class='environment'>funcdesc</b>}</tt></dt> |
| 225 | <dd> |
| 226 | Describe a module-level function. <var>parameters</var> should |
| 227 | not include the parentheses used in the call syntax. Object |
| 228 | methods are not documented using this environment. Bound object |
| 229 | methods placed in the module namespace as part of the public |
| 230 | interface of the module are documented using this, as they are |
| 231 | equivalent to normal functions for most purposes. |
| 232 | |
| 233 | <P> |
| 234 | The description should include information about the parameters |
| 235 | required and how they are used (especially whether mutable |
| 236 | objects passed as parameters are modified), side effects, and |
| 237 | possible exceptions. A small example may be provided. |
| 238 | </dd></dl> |
| 239 | |
| 240 | <dl class='envdesc'> |
| 241 | <dt><tt>\begin{<b class='environment'>funcdescni</b>}</tt> |
| 242 | <tt>{</tt><var>name</var><tt>}</tt><tt>{</tt><var>parameters</var><tt>}</tt> |
| 243 | <br /><tt>\end{<b class='environment'>funcdescni</b>}</tt></dt> |
| 244 | <dd> |
| 245 | Like <tt class='environment'>\funcdesc</tt>, but without creating any index entries. |
| 246 | </dd></dl> |
| 247 | |
| 248 | <P> |
| 249 | |
| 250 | <dl class='envdesc'> |
| 251 | <dt><tt>\begin{<b class='environment'>classdesc</b>}</tt> |
| 252 | <tt>{</tt><var>name</var><tt>}</tt><tt>{</tt><var>constructor parameters</var><tt>}</tt> |
| 253 | <br /><tt>\end{<b class='environment'>classdesc</b>}</tt></dt> |
| 254 | <dd> |
| 255 | Describe a class and its constructor. <var>constructor |
| 256 | parameters</var> should not include the <var>self</var> parameter or |
| 257 | the parentheses used in the call syntax. |
| 258 | </dd></dl> |
| 259 | |
| 260 | <P> |
| 261 | |
| 262 | <dl class='envdesc'> |
| 263 | <dt><tt>\begin{<b class='environment'>classdesc*</b>}</tt> |
| 264 | <tt>{</tt><var>name</var><tt>}</tt> |
| 265 | <br /><tt>\end{<b class='environment'>classdesc*</b>}</tt></dt> |
| 266 | <dd> |
| 267 | Describe a class without describing the constructor. This can |
| 268 | be used to describe classes that are merely containers for |
| 269 | attributes or which should never be instantiated or subclassed |
| 270 | by user code. |
| 271 | </dd></dl> |
| 272 | |
| 273 | <P> |
| 274 | |
| 275 | <dl class='envdesc'> |
| 276 | <dt><tt>\begin{<b class='environment'>memberdesc</b>}</tt> |
| 277 | <tt>[</tt><var>type name</var><tt>]</tt><tt>{</tt><var>name</var><tt>}</tt> |
| 278 | <br /><tt>\end{<b class='environment'>memberdesc</b>}</tt></dt> |
| 279 | <dd> |
| 280 | Describe an object data attribute. The description should |
| 281 | include information about the type of the data to be expected |
| 282 | and whether it may be changed directly. |
| 283 | </dd></dl> |
| 284 | |
| 285 | <dl class='envdesc'> |
| 286 | <dt><tt>\begin{<b class='environment'>memberdescni</b>}</tt> |
| 287 | <tt>[</tt><var>type name</var><tt>]</tt><tt>{</tt><var>name</var><tt>}</tt> |
| 288 | <br /><tt>\end{<b class='environment'>memberdescni</b>}</tt></dt> |
| 289 | <dd> |
| 290 | Like <tt class='environment'>\memberdesc</tt>, but without creating any index entries. |
| 291 | </dd></dl> |
| 292 | |
| 293 | <P> |
| 294 | |
| 295 | <dl class='envdesc'> |
| 296 | <dt><tt>\begin{<b class='environment'>methoddesc</b>}</tt> |
| 297 | <tt>[</tt><var>type name</var><tt>]</tt><tt>{</tt><var>name</var><tt>}</tt><tt>{</tt><var>parameters</var><tt>}</tt> |
| 298 | <br /><tt>\end{<b class='environment'>methoddesc</b>}</tt></dt> |
| 299 | <dd> |
| 300 | Describe an object method. <var>parameters</var> should not include |
| 301 | the <var>self</var> parameter or the parentheses used in the call |
| 302 | syntax. The description should include similar information to |
| 303 | that described for <tt class='environment'>\funcdesc</tt>. |
| 304 | </dd></dl> |
| 305 | |
| 306 | <dl class='envdesc'> |
| 307 | <dt><tt>\begin{<b class='environment'>methoddescni</b>}</tt> |
| 308 | <tt>[</tt><var>type name</var><tt>]</tt><tt>{</tt><var>name</var><tt>}</tt><tt>{</tt><var>parameters</var><tt>}</tt> |
| 309 | <br /><tt>\end{<b class='environment'>methoddescni</b>}</tt></dt> |
| 310 | <dd> |
| 311 | Like <tt class='environment'>\methoddesc</tt>, but without creating any index entries. |
| 312 | </dd></dl> |
| 313 | |
| 314 | <P> |
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