1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Required Concepts</title> 5<link rel="stylesheet" href="../../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../index.html" title="Chapter 1. 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The template parameters can 31 be grouped with respect to those requirements. 32 </p> 33<div class="informaltable"><table class="table"> 34<colgroup> 35<col> 36<col> 37<col> 38<col> 39<col> 40<col> 41</colgroup> 42<thead><tr> 43<th> 44 </th> 45<th> 46 <p> 47 used in 48 </p> 49 </th> 50<th> 51 <p> 52 Kind 53 </p> 54 </th> 55<th> 56 <p> 57 Parameter 58 </p> 59 </th> 60<th> 61 <p> 62 Instance 63 </p> 64 </th> 65<th> 66 <p> 67 Description 68 </p> 69 </th> 70</tr></thead> 71<tbody> 72<tr> 73<td> 74 <p> 75 Domain order 76 </p> 77 </td> 78<td> 79 <p> 80 <code class="computeroutput"><span class="identifier">Intervals</span><span class="special">,</span> 81 <span class="identifier">Sets</span><span class="special">,</span> 82 <span class="identifier">Maps</span></code> 83 </p> 84 </td> 85<td> 86 <p> 87 <code class="computeroutput"><span class="keyword">typename</span></code> 88 </p> 89 </td> 90<td> 91 <p> 92 <code class="computeroutput"><span class="identifier">DomainT</span></code> 93 </p> 94 </td> 95<td> 96 </td> 97<td> 98 <p> 99 For the type <code class="computeroutput"><span class="identifier">DomainT</span></code> 100 of key elements <code class="computeroutput"><span class="special">...</span></code> 101 </p> 102 </td> 103</tr> 104<tr> 105<td> 106 </td> 107<td> 108 </td> 109<td> 110 <p> 111 <code class="computeroutput"><span class="keyword">template</span></code> 112 </p> 113 </td> 114<td> 115 <p> 116 <code class="computeroutput"><span class="identifier">Compare</span></code> 117 </p> 118 </td> 119<td> 120 <p> 121 <code class="computeroutput"><span class="identifier">Compare</span><span class="special"><</span><span class="identifier">DomainT</span><span class="special">></span></code> 122 </p> 123 </td> 124<td> 125 <p> 126 <code class="computeroutput"><span class="special">...</span></code> there is an order 127 <code class="computeroutput"><span class="identifier">Compare</span></code> 128 </p> 129 </td> 130</tr> 131<tr> 132<td> 133 <p> 134 Interval type 135 </p> 136 </td> 137<td> 138 <p> 139 <code class="computeroutput"><span class="identifier">interval_sets</span><span class="special">/</span><span class="identifier">maps</span></code> 140 </p> 141 </td> 142<td> 143 <p> 144 <code class="computeroutput"><span class="keyword">typename</span></code> 145 </p> 146 </td> 147<td> 148 <p> 149 <code class="computeroutput"><span class="identifier">IntervalT</span></code> 150 </p> 151 </td> 152<td> 153 </td> 154<td> 155 <p> 156 <code class="computeroutput"><span class="special">...</span></code> the <code class="computeroutput"><span class="identifier">IntervalT</span></code> parameter has to use 157 the same element type and order. 158 </p> 159 </td> 160</tr> 161<tr> 162<td> 163 <p> 164 Codomain aggregation 165 </p> 166 </td> 167<td> 168 <p> 169 <code class="computeroutput"><span class="identifier">Maps</span></code> 170 </p> 171 </td> 172<td> 173 <p> 174 <code class="computeroutput"><span class="keyword">typename</span></code> 175 </p> 176 </td> 177<td> 178 <p> 179 <code class="computeroutput"><span class="identifier">CodomainT</span></code> 180 </p> 181 </td> 182<td> 183 </td> 184<td> 185 <p> 186 For the type <code class="computeroutput"><span class="identifier">CodomainT</span></code> 187 of associated values <code class="computeroutput"><span class="special">...</span></code> 188 </p> 189 </td> 190</tr> 191<tr> 192<td> 193 </td> 194<td> 195 </td> 196<td> 197 <p> 198 <code class="computeroutput"><span class="keyword">template</span></code> 199 </p> 200 </td> 201<td> 202 <p> 203 <code class="computeroutput"><span class="identifier">Combine</span></code> 204 </p> 205 </td> 206<td> 207 <p> 208 <code class="computeroutput"><span class="identifier">Combine</span><span class="special"><</span><span class="identifier">CodomainT</span><span class="special">></span></code> 209 </p> 210 </td> 211<td> 212 <p> 213 <code class="computeroutput"><span class="special">...</span></code> there is a binary 214 functor <code class="computeroutput"><span class="identifier">Combine</span><span class="special"><</span><span class="identifier">CodomainT</span><span class="special">>()</span></code> to combine them 215 </p> 216 </td> 217</tr> 218<tr> 219<td> 220 </td> 221<td> 222 </td> 223<td> 224 </td> 225<td> 226 </td> 227<td> 228 <p> 229 <code class="computeroutput"><span class="identifier">Inverse</span><span class="special"><</span><span class="identifier">Combine</span><span class="special"><</span><span class="identifier">CodomainT</span><span class="special">>></span></code> 230 </p> 231 </td> 232<td> 233 <p> 234 <code class="computeroutput"><span class="special">...</span></code> and implicitly 235 an <code class="computeroutput"><span class="identifier">Inverse</span></code> functor 236 to inversely combine them. 237 </p> 238 </td> 239</tr> 240<tr> 241<td> 242 </td> 243<td> 244 </td> 245<td> 246 <p> 247 <code class="computeroutput"><span class="keyword">template</span></code> 248 </p> 249 </td> 250<td> 251 <p> 252 <code class="computeroutput"><span class="identifier">Section</span></code> 253 </p> 254 </td> 255<td> 256 <p> 257 <code class="computeroutput"><span class="identifier">Section</span><span class="special"><</span><span class="identifier">CodomainT</span><span class="special">></span></code> 258 </p> 259 </td> 260<td> 261 <p> 262 Intersection is propagated to CodomainT values via functor <code class="computeroutput"><span class="identifier">Section</span><span class="special"><</span><span class="identifier">CodomainT</span><span class="special">>()</span></code> 263 </p> 264 </td> 265</tr> 266<tr> 267<td> 268 <p> 269 Memory allocation 270 </p> 271 </td> 272<td> 273 <p> 274 <code class="computeroutput"><span class="identifier">Sets</span><span class="special">,</span> 275 <span class="identifier">Maps</span></code> 276 </p> 277 </td> 278<td> 279 <p> 280 <code class="computeroutput"><span class="keyword">template</span></code> 281 </p> 282 </td> 283<td> 284 <p> 285 <code class="computeroutput"><span class="identifier">Alloc</span></code> 286 </p> 287 </td> 288<td> 289 <p> 290 <code class="computeroutput"><span class="identifier">Alloc</span><span class="special"><</span></code><span class="emphasis"><em>various</em></span><code class="computeroutput"><span class="special">></span></code> 291 </p> 292 </td> 293<td> 294 <p> 295 An allocator can be chosen for memory allocation. 296 </p> 297 </td> 298</tr> 299</tbody> 300</table></div> 301<h5> 302<a name="boost_icl.interface.required_concepts.h0"></a> 303 <span class="phrase"><a name="boost_icl.interface.required_concepts.requirements_on_domaint"></a></span><a class="link" href="required_concepts.html#boost_icl.interface.required_concepts.requirements_on_domaint">Requirements 304 on DomainT</a> 305 </h5> 306<p> 307 The next table gives an overview over the requirements for template parameter 308 <code class="computeroutput"><span class="identifier">DomainT</span></code>. Some requirements 309 are dependent on <span class="emphasis"><em>conditions</em></span>. Column <span class="emphasis"><em>operators</em></span> 310 shows the operators and functions that are expected for <code class="computeroutput"><span class="identifier">DomainT</span></code>, 311 if the default order <code class="computeroutput"><span class="identifier">Compare</span> <span class="special">=</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">less</span></code> is used. 312 </p> 313<div class="informaltable"><table class="table"> 314<colgroup> 315<col> 316<col> 317<col> 318<col> 319</colgroup> 320<thead><tr> 321<th> 322 <p> 323 Parameter 324 </p> 325 </th> 326<th> 327 <p> 328 Condition 329 </p> 330 </th> 331<th> 332 <p> 333 Operators 334 </p> 335 </th> 336<th> 337 <p> 338 Requirement 339 </p> 340 </th> 341</tr></thead> 342<tbody> 343<tr> 344<td> 345 <p> 346 <code class="computeroutput"><span class="identifier">DomainT</span></code> 347 </p> 348 </td> 349<td> 350 </td> 351<td> 352 <p> 353 <code class="computeroutput"><span class="identifier">DomainT</span><span class="special">(),</span> 354 <span class="special"><</span></code> 355 </p> 356 </td> 357<td> 358 <p> 359 <code class="computeroutput"><span class="identifier">Regular</span><span class="special"><</span><span class="identifier">DomainT</span><span class="special">></span> 360 <span class="special">&&</span> <span class="identifier">StrictWeakOrdering</span><span class="special"><</span><span class="identifier">DomainT</span><span class="special">,</span><span class="identifier">Compare</span><span class="special">></span></code> 361 </p> 362 </td> 363</tr> 364<tr> 365<td> 366 </td> 367<td> 368 </td> 369<td> 370 <p> 371 <code class="computeroutput"><span class="special">++,</span> <span class="identifier">unit_element</span><span class="special"><</span><span class="identifier">CodomainT</span><span class="special">>::</span><span class="identifier">value</span><span class="special">()</span></code> 372 </p> 373 </td> 374<td> 375 <p> 376 <code class="computeroutput"><span class="special">&&</span> <span class="special">(</span><span class="identifier">IsIncrementable</span><span class="special"><</span><span class="identifier">DomainT</span><span class="special">>||</span><span class="identifier">HasUnitElement</span><span class="special"><</span><span class="identifier">DomainT</span><span class="special">>)</span></code> 377 </p> 378 </td> 379</tr> 380<tr> 381<td> 382 </td> 383<td> 384 <p> 385 <code class="computeroutput"><span class="identifier">IsIntegral</span><span class="special"><</span><span class="identifier">DomainT</span><span class="special">></span></code> 386 </p> 387 </td> 388<td> 389 <p> 390 <code class="computeroutput"><span class="special">++,</span> <span class="special">--</span></code> 391 </p> 392 </td> 393<td> 394 <p> 395 <code class="computeroutput"><span class="identifier">IsIncrementable</span><span class="special"><</span><span class="identifier">DomainT</span><span class="special">></span> <span class="special">&&</span> 396 <span class="identifier">IsDecrementable</span><span class="special"><</span><span class="identifier">DomainT</span><span class="special">></span></code> 397 </p> 398 </td> 399</tr> 400</tbody> 401</table></div> 402<p> 403 A domain type <code class="computeroutput"><span class="identifier">DomainT</span></code> for 404 intervals and interval containers has to satisfy the requirements of concept 405 <a href="http://www.informit.com/guides/content.aspx?g=cplusplus&seqNum=314" target="_top"><code class="computeroutput"><span class="identifier">Regular</span></code></a> which implies among other 406 properties the existence of a copy and a default constructor. In addition 407 <code class="computeroutput"><span class="identifier">IsIncrementable</span></code> <span class="bold"><strong>or</strong></span> <code class="computeroutput"><span class="identifier">HasUnitElement</span></code> 408 is required for <code class="computeroutput"><span class="identifier">DomainT</span></code>. 409 In the <span class="bold"><strong>icl</strong></span> we represent an empty closed 410 interval as interval <code class="computeroutput"><span class="special">[</span><span class="identifier">b</span><span class="special">,</span><span class="identifier">a</span><span class="special">]</span></code> 411 where <code class="computeroutput"><span class="identifier">a</span> <span class="special"><</span> 412 <span class="identifier">b</span></code> (here <code class="computeroutput"><span class="special"><</span></code> 413 represents <code class="computeroutput"><span class="identifier">Compare</span><span class="special"><</span><span class="identifier">DomainT</span><span class="special">>()</span></code>). 414 To construct one of these empty intervals as default constructor for any 415 type <code class="computeroutput"><span class="identifier">DomainT</span></code> we choose <code class="computeroutput"><span class="special">[</span><span class="number">1</span><span class="special">,</span><span class="number">0</span><span class="special">]</span></code>, where 416 <code class="computeroutput"><span class="number">0</span></code> is a null-value or <code class="computeroutput"><span class="identifier">identity_element</span></code> and <code class="computeroutput"><span class="number">1</span></code> 417 is a one-value or <code class="computeroutput"><span class="identifier">unit_element</span></code>: 418</p> 419<pre class="programlisting"><span class="identifier">interval</span><span class="special">()</span> <span class="special">:=</span> <span class="special">[</span><span class="identifier">unit_element</span><span class="special"><</span><span class="identifier">DomainT</span><span class="special">>::</span><span class="identifier">value</span><span class="special">(),</span> <span class="identifier">identity_element</span><span class="special"><</span><span class="identifier">DomainT</span><span class="special">>::</span><span class="identifier">value</span><span class="special">()]</span> <span class="comment">//pseudocode</span> 420</pre> 421<p> 422 <code class="computeroutput"><span class="identifier">Identity_elements</span></code> are implemented 423 via call of the default constructor of <code class="computeroutput"><span class="identifier">DomainT</span></code>. 424 A <code class="computeroutput"><span class="identifier">unit_element</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span><span class="special">()</span></code> 425 is implemented <code class="computeroutput">by default</code> 426 as a <code class="computeroutput"><span class="identifier">identity_element</span></code>, that 427 is incremented once. 428</p> 429<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">Type</span><span class="special">></span> 430<span class="keyword">inline</span> <span class="identifier">Type</span> <span class="identifier">unit_element</span><span class="special"><</span><span class="identifier">Type</span><span class="special">>::</span><span class="identifier">value</span><span class="special">(){</span> <span class="keyword">return</span> <span class="identifier">succ</span><span class="special">(</span><span class="identifier">identity_element</span><span class="special"><</span><span class="identifier">Type</span><span class="special">>::</span><span class="identifier">value</span><span class="special">());</span> <span class="special">};</span> 431</pre> 432<p> 433 So a type <code class="computeroutput"><span class="identifier">DomainT</span></code> that is 434 <code class="computeroutput"><span class="identifier">incrementable</span></code> will also have 435 an <code class="computeroutput"><span class="identifier">unit_element</span></code>. If it does 436 not, a <code class="computeroutput"><span class="identifier">unit_element</span></code> can be 437 provided. A <code class="computeroutput"><span class="identifier">unit_element</span></code> 438 can be any value, that is greater as the <code class="computeroutput"><span class="identifier">identity_element</span></code> 439 in the <code class="computeroutput"><span class="identifier">Compare</span></code> order given. 440 An example of a type, that has an <code class="computeroutput"><span class="identifier">identity_element</span></code> 441 but no increment operation is <code class="computeroutput"><span class="identifier">string</span></code>. 442 So for <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span></code> a unit_element is implemented like 443 this: 444</p> 445<pre class="programlisting"><span class="comment">// Smallest 'visible' string that is greater than the empty string.</span> 446<span class="keyword">template</span> <span class="special"><></span> 447<span class="keyword">inline</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">unit_element</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">>::</span><span class="identifier">value</span><span class="special">(){</span> <span class="keyword">return</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">(</span><span class="string">" "</span><span class="special">);</span> <span class="special">};</span> 448</pre> 449<p> 450 </p> 451<p> 452 Just as for the key type of std::sets and maps template parameter <code class="computeroutput"><span class="identifier">Compare</span></code> is required to be a <a href="http://en.wikipedia.org/wiki/Strict_weak_ordering" target="_top">strict 453 weak ordering</a> on <code class="computeroutput"><span class="identifier">DomainT</span></code>. 454 </p> 455<p> 456 Finally, if <code class="computeroutput"><span class="identifier">DomainT</span></code> is an 457 integral type, <code class="computeroutput"><span class="identifier">DomainT</span></code> needs 458 to be <code class="computeroutput"><span class="identifier">incrementable</span></code> and 459 <code class="computeroutput"><span class="identifier">decrementable</span></code>. This <span class="emphasis"><em>'bicrementability'</em></span> 460 needs to be implemented on the smallest possible unit of the integral type. 461 This seems like being trivial but there are types like e.g. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">date_time</span><span class="special">::</span><span class="identifier">ptime</span></code>, that are integral in nature but 462 do not provide the required in- and decrementation on the least incrementable 463 unit. For <code class="computeroutput"><a class="link" href="../../boost/icl/interval.html" title="Struct template interval">icl::intervals</a></code> 464 incementation and decementation is used for computations between open to 465 closed interval borders like e.g. <code class="computeroutput"><span class="special">[</span><span class="number">2</span><span class="special">,</span><span class="number">43</span><span class="special">)</span> <span class="special">==</span> <span class="special">[</span><span class="number">2</span><span class="special">,</span><span class="number">42</span><span class="special">]</span></code>. Such computations always need only one 466 in- or decrementation, if <code class="computeroutput"><span class="identifier">DomainT</span></code> 467 is an integral type. 468 </p> 469<h6> 470<a name="boost_icl.interface.required_concepts.h1"></a> 471 <span class="phrase"><a name="boost_icl.interface.required_concepts.requirements_on_intervalt"></a></span><a class="link" href="required_concepts.html#boost_icl.interface.required_concepts.requirements_on_intervalt">Requirements 472 on IntervalT</a> 473 </h6> 474<p> 475 Requirements on the <code class="computeroutput"><span class="identifier">IntervalT</span></code> 476 parameter are closely related to the <code class="computeroutput"><span class="identifier">DomainT</span></code> 477 parameter. <code class="computeroutput"><span class="identifier">IntervalT</span></code> has 478 two associated types itself for an element type and a compare order that 479 have to be consistent with the element and order parameters of their interval 480 containers. <code class="computeroutput"><span class="identifier">IntervalT</span></code> then 481 has to implement an order called <code class="computeroutput"><span class="identifier">exclusive_less</span></code>. 482 Two intervals <code class="computeroutput"><span class="identifier">x</span><span class="special">,</span> 483 <span class="identifier">y</span></code> are exclusive_less 484</p> 485<pre class="programlisting"><span class="identifier">icl</span><span class="special">::</span><span class="identifier">exclusive_less</span><span class="special">(</span><span class="identifier">x</span><span class="special">,</span> <span class="identifier">y</span><span class="special">)</span></pre> 486<p> 487 if all <code class="computeroutput"><span class="identifier">DomainT</span></code> elements of 488 <code class="computeroutput"><span class="identifier">x</span></code> are less than elements 489 of <code class="computeroutput"><span class="identifier">y</span></code> in the <code class="computeroutput"><span class="identifier">Compare</span></code> order. 490 </p> 491<div class="informaltable"><table class="table"> 492<colgroup> 493<col> 494<col> 495<col> 496</colgroup> 497<thead><tr> 498<th> 499 <p> 500 Parameter 501 </p> 502 </th> 503<th> 504 <p> 505 Operators 506 </p> 507 </th> 508<th> 509 <p> 510 Requirement 511 </p> 512 </th> 513</tr></thead> 514<tbody><tr> 515<td> 516 <p> 517 <code class="computeroutput"><span class="identifier">IntervalT</span></code> 518 </p> 519 </td> 520<td> 521 <p> 522 <code class="computeroutput"><span class="identifier">exclusive_less</span></code> 523 </p> 524 </td> 525<td> 526 <p> 527 <code class="computeroutput"><span class="identifier">IsExclusiveLessComparable</span><span class="special"><</span><span class="identifier">Interval</span><span class="special"><</span><span class="identifier">DomainT</span><span class="special">,</span><span class="identifier">Compare</span><span class="special">></span> <span class="special">></span></code> 528 </p> 529 </td> 530</tr></tbody> 531</table></div> 532<h5> 533<a name="boost_icl.interface.required_concepts.h2"></a> 534 <span class="phrase"><a name="boost_icl.interface.required_concepts.requirements_on_codomaint"></a></span><a class="link" href="required_concepts.html#boost_icl.interface.required_concepts.requirements_on_codomaint">Requirements 535 on CodomainT</a> 536 </h5> 537<p> 538 Summarized in the next table are requirements for template parameter <code class="computeroutput"><span class="identifier">CodomainT</span></code> of associated values for <code class="computeroutput"><span class="identifier">Maps</span></code>. Again there are <span class="emphasis"><em>conditions</em></span> 539 for some of the requirements. Column <span class="emphasis"><em>operators</em></span> contains 540 the operators and functions required for <code class="computeroutput"><span class="identifier">CodomainT</span></code>, 541 if we are using the default combiner <code class="computeroutput"><span class="identifier">Combine</span> 542 <span class="special">=</span> <span class="identifier">icl</span><span class="special">::</span><span class="identifier">inplace_plus</span></code>. 543 </p> 544<div class="informaltable"><table class="table"> 545<colgroup> 546<col> 547<col> 548<col> 549<col> 550</colgroup> 551<thead><tr> 552<th> 553 <p> 554 Parameter 555 </p> 556 </th> 557<th> 558 <p> 559 Condition 560 </p> 561 </th> 562<th> 563 <p> 564 Operators 565 </p> 566 </th> 567<th> 568 <p> 569 Requirement 570 </p> 571 </th> 572</tr></thead> 573<tbody> 574<tr> 575<td> 576 <p> 577 <code class="computeroutput"><span class="identifier">CodomainT</span></code> 578 </p> 579 </td> 580<td> 581 <p> 582 <code class="computeroutput"><span class="identifier">add</span></code>, <code class="computeroutput"><span class="identifier">subtract</span></code>, <code class="computeroutput"><span class="identifier">intersect</span></code> 583 unused 584 </p> 585 </td> 586<td> 587 <p> 588 <code class="computeroutput"><span class="identifier">CodomainT</span><span class="special">(),</span> 589 <span class="special">==</span></code> 590 </p> 591 </td> 592<td> 593 <p> 594 <code class="computeroutput"><span class="identifier">Regular</span><span class="special"><</span><span class="identifier">CodomainT</span><span class="special">></span></code> 595 which implies 596 </p> 597 </td> 598</tr> 599<tr> 600<td> 601 </td> 602<td> 603 </td> 604<td> 605 </td> 606<td> 607 <p> 608 <code class="computeroutput"><span class="identifier">DefaultConstructible</span><span class="special"><</span><span class="identifier">CodomainT</span><span class="special">></span> <span class="special">&&</span> 609 <span class="identifier">EqualityComparable</span><span class="special"><</span><span class="identifier">CodomainT</span><span class="special">></span></code> 610 </p> 611 </td> 612</tr> 613<tr> 614<td> 615 </td> 616<td> 617 <p> 618 only <code class="computeroutput"><span class="identifier">add</span></code> used 619 </p> 620 </td> 621<td> 622 <p> 623 <code class="computeroutput"><span class="special">+=</span></code> 624 </p> 625 </td> 626<td> 627 <p> 628 <code class="computeroutput"><span class="special">&&</span> <span class="identifier">Combinable</span><span class="special"><</span><span class="identifier">CodomainT</span><span class="special">,</span><span class="identifier">Combine</span><span class="special">></span></code> 629 </p> 630 </td> 631</tr> 632<tr> 633<td> 634 </td> 635<td> 636 <p> 637 ... and also <code class="computeroutput"><span class="identifier">subtract</span></code> 638 used 639 </p> 640 </td> 641<td> 642 <p> 643 <code class="computeroutput"><span class="special">-=</span></code> 644 </p> 645 </td> 646<td> 647 <p> 648 <code class="computeroutput"><span class="special">&&</span> <span class="identifier">Combinable</span><span class="special"><</span><span class="identifier">CodomainT</span><span class="special">,</span><span class="identifier">Inverse</span><span class="special"><</span><span class="identifier">Combine</span><span class="special">></span> <span class="special">></span></code> 649 </p> 650 </td> 651</tr> 652<tr> 653<td> 654 </td> 655<td> 656 <p> 657 <code class="computeroutput"><span class="identifier">Section</span></code> used and 658 <code class="computeroutput"><span class="identifier">CodomainT</span></code> is a 659 set 660 </p> 661 </td> 662<td> 663 <p> 664 <code class="computeroutput"><span class="special">&=</span></code> 665 </p> 666 </td> 667<td> 668 <p> 669 <code class="computeroutput"><span class="special">&&</span> <span class="identifier">Intersectable</span><span class="special"><</span><span class="identifier">CodomainT</span><span class="special">,</span><span class="identifier">Section</span><span class="special">></span></code> 670 </p> 671 </td> 672</tr> 673</tbody> 674</table></div> 675<p> 676 The requirements on the type <code class="computeroutput"><span class="identifier">CodomainT</span></code> 677 of associated values for a <code class="computeroutput"><a class="link" href="../../boost/icl/map.html" title="Class template map">icl::map</a></code> 678 or <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_map</a></code> depend 679 on the usage of their aggregation functionality. If aggregation on overlap 680 is never used, that is to say that none of the addition, subtraction and 681 intersection operations (<code class="computeroutput"><span class="special">+,</span> <span class="special">+=,</span> <span class="identifier">add</span></code>, 682 <code class="computeroutput"><span class="special">-,</span> <span class="special">-=,</span> 683 <span class="identifier">subtract</span></code>, &, &=, add_intersection) 684 are used on the <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_map</a></code>, 685 then <code class="computeroutput"><span class="identifier">CodomainT</span></code> only needs 686 to be <a href="http://www.informit.com/guides/content.aspx?g=cplusplus&seqNum=314" target="_top">Regular</a>. 687 </p> 688<p> 689 <span class="emphasis"><em><span class="bold"><strong>Regular</strong></span></em></span> object semantics 690 implies <code class="computeroutput"><span class="identifier">DefaultConstructible</span></code> 691 and <code class="computeroutput"><span class="identifier">EqualityComparable</span></code> which 692 means it has a default ctor <code class="computeroutput"><span class="identifier">CodomainT</span><span class="special">()</span></code> and an <code class="computeroutput"><span class="keyword">operator</span> 693 <span class="special">==</span></code>. 694 </p> 695<p> 696 Use <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_maps</a></code> 697 <span class="emphasis"><em><span class="bold"><strong>without aggregation</strong></span></em></span>, 698 if the associated values are not addable but still are attached to intervals 699 so you want to use <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_maps</a></code> 700 to handle them. As long as those values are added with <code class="computeroutput"><span class="identifier">insert</span></code> 701 and deleted with <code class="computeroutput"><span class="identifier">erase</span></code> <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_maps</a></code> will work fine with 702 such values. 703 </p> 704<p> 705 If <span class="emphasis"><em><span class="bold"><strong>only addition</strong></span></em></span> is 706 used via <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_map's</a></code> 707 <code class="computeroutput"><span class="special">+,</span> <span class="special">+=</span></code> 708 or <code class="computeroutput"><span class="identifier">add</span></code> but no subtraction, 709 then <code class="computeroutput"><span class="identifier">CodomainT</span></code> need to be 710 <code class="computeroutput"><span class="identifier">Combinable</span></code> for functor template 711 <code class="computeroutput"><span class="identifier">Combine</span></code>. That means in most 712 cases when the default implementation <code class="computeroutput"><span class="identifier">inplace_plus</span></code> 713 for <code class="computeroutput"><span class="identifier">Combine</span></code> is used, that 714 <code class="computeroutput"><span class="identifier">CodomainT</span></code> has to implement 715 <code class="computeroutput"><span class="keyword">operator</span> <span class="special">+=</span></code>. 716 </p> 717<p> 718 For associated value types, that are addable but not subtractable like e.g. 719 <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span></code> it usually makes sense to use addition 720 to combine values but the inverse combination is not desired. 721</p> 722<pre class="programlisting"><span class="identifier">interval_map</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">></span> <span class="identifier">cat_map</span><span class="special">;</span> 723<span class="identifier">cat_map</span> <span class="special">+=</span> <span class="identifier">make_pair</span><span class="special">(</span><span class="identifier">interval</span><span class="special"><</span><span class="keyword">int</span><span class="special">>::</span><span class="identifier">rightopen</span><span class="special">(</span><span class="number">1</span><span class="special">,</span><span class="number">5</span><span class="special">),</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">(</span><span class="string">"Hello"</span><span class="special">));</span> 724<span class="identifier">cat_map</span> <span class="special">+=</span> <span class="identifier">make_pair</span><span class="special">(</span><span class="identifier">interval</span><span class="special"><</span><span class="keyword">int</span><span class="special">>::</span><span class="identifier">rightopen</span><span class="special">(</span><span class="number">3</span><span class="special">,</span><span class="number">7</span><span class="special">),</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">(</span><span class="string">" world"</span><span class="special">));</span> 725<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"cat_map: "</span> <span class="special"><<</span> <span class="identifier">cat_map</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span> 726<span class="comment">//cat_map: {([1,3)->Hello)([3,5)->Hello world)([5,7)-> world)}</span> 727</pre> 728<p> 729 </p> 730<p> 731 For <span class="emphasis"><em>complete aggregation functionality</em></span> an inverse aggregation 732 functor on a <code class="computeroutput"><span class="identifier">Map</span></code>'s <code class="computeroutput"><span class="identifier">CodomainT</span></code> is needed. The icl provides a 733 metafunction <code class="computeroutput"><a class="link" href="../../boost/icl/inverse.html" title="Struct template inverse">inverse</a></code> for 734 that purpose. Using the default <code class="computeroutput"><span class="identifier">Combine</span> 735 <span class="special">=</span> <span class="identifier">inplace_plus</span></code> 736 that relies on the existence of <code class="computeroutput"><span class="keyword">operator</span> 737 <span class="special">+=</span></code> on type <code class="computeroutput"><span class="identifier">CodomainT</span></code> 738 metafunction <code class="computeroutput"><a class="link" href="../../boost/icl/inverse.html" title="Struct template inverse">inverse</a></code> will 739 infer <code class="computeroutput"><a class="link" href="../../boost/icl/inplace_minus.html" title="Struct template inplace_minus">inplace_minus</a></code> 740 as inverse functor, that requires <code class="computeroutput"><span class="keyword">operator</span> 741 <span class="special">-=</span></code> on type <code class="computeroutput"><span class="identifier">CodomainT</span></code>. 742 </p> 743<p> 744 In the icl's design we make the assumption, in particular for the default 745 setting of parameters <code class="computeroutput"><span class="identifier">Combine</span> <span class="special">=</span> </code><code class="computeroutput"><a class="link" href="../../boost/icl/inplace_minus.html" title="Struct template inplace_minus">inplace_plus</a></code>, 746 that type <code class="computeroutput"><span class="identifier">CodomainT</span></code> has a 747 neutral element or <code class="computeroutput"><span class="identifier">identity_element</span></code> 748 with respect to the <code class="computeroutput"><span class="identifier">Combine</span></code> 749 functor. 750 </p> 751</div> 752<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 753<td align="left"></td> 754<td align="right"><div class="copyright-footer">Copyright © 2007-2010 Joachim 755 Faulhaber<br>Copyright © 1999-2006 Cortex Software 756 GmbH<p> 757 Distributed under the Boost Software License, Version 1.0. (See accompanying 758 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 759 </p> 760</div></td> 761</tr></table> 762<hr> 763<div class="spirit-nav"> 764<a accesskey="p" href="../interface.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../interface.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="associated_types.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 765</div> 766</body> 767</html> 768
