mpusz/mp-units
1
0
Fork 1
mirror of https://github.com/mpusz/mp-units.git synced 2025-06-24 16:51:33 +02:00
Code Issues Packages Projects Releases Wiki Activity

Deployed 93f3be47 to HEAD with MkDocs 1.6.1 and mike 2.1.3

Browse Source
This commit is contained in:
github-actions
2025-06-20 15:24:19 +00:00
parent 1cbda4b2e4
commit dcc831954c
6 changed files with 70 additions and 40 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
HEAD/blog/2024/10/21/international-system-of-quantities-isq-part-3---modeling-isq/index.html
View File

@ -2726,12 +2726,13 @@ quantities of the same kind.</p>
</span><span id="__span-5-6"><a id="__codelineno-5-6" name="__codelineno-5-6" href="#__codelineno-5-6"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">radius</span><span class="p">));</span>
</span></code></pre></div>
<p>Explicit conversions are forced by passing the quantity to a call operator of a <code>quantity_spec</code>
type:</p>
type or by calling <code>quantity</code>'s explicit constructor:</p>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-6-1"><a id="__codelineno-6-1" name="__codelineno-6-1" href="#__codelineno-6-1"></a><span class="kt">void</span><span class="w"> </span><span class="nf">foo</span><span class="p">(</span><span class="n">quantity</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">[</span><span class="n">m</span><span class="p">]</span><span class="o">&gt;</span><span class="w"> </span><span class="n">q</span><span class="p">);</span>
</span></code></pre></div>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-7-1"><a id="__codelineno-7-1" name="__codelineno-7-1" href="#__codelineno-7-1"></a><span class="n">quantity</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">[</span><span class="n">m</span><span class="p">]</span><span class="o">&gt;</span><span class="w"> </span><span class="n">q1</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">42</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">m</span><span class="p">;</span>
</span><span id="__span-7-2"><a id="__codelineno-7-2" name="__codelineno-7-2" href="#__codelineno-7-2"></a><span class="n">quantity</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">[</span><span class="n">m</span><span class="p">]</span><span class="o">&gt;</span><span class="w"> </span><span class="n">q2</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">(</span><span class="n">q1</span><span class="p">);</span><span class="w"> </span><span class="c1">// explicit quantity conversion</span>
</span><span id="__span-7-3"><a id="__codelineno-7-3" name="__codelineno-7-3" href="#__codelineno-7-3"></a><span class="n">foo</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">(</span><span class="n">q1</span><span class="p">));</span><span class="w"> </span><span class="c1">// explicit quantity conversion</span>
</span><span id="__span-7-3"><a id="__codelineno-7-3" name="__codelineno-7-3" href="#__codelineno-7-3"></a><span class="n">quantity</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">[</span><span class="n">m</span><span class="p">]</span><span class="o">&gt;</span><span class="w"> </span><span class="n">q3</span><span class="p">(</span><span class="n">q1</span><span class="p">);</span><span class="w"> </span><span class="c1">// direct initialization</span>
</span><span id="__span-7-4"><a id="__codelineno-7-4" name="__codelineno-7-4" href="#__codelineno-7-4"></a><span class="n">foo</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">(</span><span class="n">q1</span><span class="p">));</span><span class="w"> </span><span class="c1">// explicit quantity conversion</span>
</span></code></pre></div>
</li>
<li>

2
HEAD/feed_json_updated.json
View File

File diff suppressed because one or more lines are too long

2
HEAD/feed_rss_created.xml
View File

File diff suppressed because one or more lines are too long

2
HEAD/feed_rss_updated.xml
View File

File diff suppressed because one or more lines are too long

2
HEAD/search/search_index.json
View File

File diff suppressed because one or more lines are too long

97
HEAD/users_guide/framework_basics/systems_of_quantities/index.html
View File

@ -2681,6 +2681,13 @@ the first common node in a hierarchy tree of the same kind. For example:</p>
</span><span id="__span-6-2"><a id="__codelineno-6-2" name="__codelineno-6-2" href="#__codelineno-6-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">radius</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">));</span>
</span><span id="__span-6-3"><a id="__codelineno-6-3" name="__codelineno-6-3" href="#__codelineno-6-3"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">radius</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">));</span>
</span></code></pre></div>
<p>Implicit conversions are allowed on copy-initialization:</p>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-7-1"><a id="__codelineno-7-1" name="__codelineno-7-1" href="#__codelineno-7-1"></a><span class="kt">void</span><span class="w"> </span><span class="nf">foo</span><span class="p">(</span><span class="n">quantity</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">[</span><span class="n">m</span><span class="p">]</span><span class="o">&gt;</span><span class="w"> </span><span class="n">q</span><span class="p">);</span>
</span></code></pre></div>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-8-1"><a id="__codelineno-8-1" name="__codelineno-8-1" href="#__codelineno-8-1"></a><span class="n">quantity</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">[</span><span class="n">m</span><span class="p">]</span><span class="o">&gt;</span><span class="w"> </span><span class="n">q1</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">42</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">m</span><span class="p">;</span>
</span><span id="__span-8-2"><a id="__codelineno-8-2" name="__codelineno-8-2" href="#__codelineno-8-2"></a><span class="n">quantity</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">[</span><span class="n">m</span><span class="p">]</span><span class="o">&gt;</span><span class="w"> </span><span class="n">q2</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">q1</span><span class="p">;</span><span class="w"> </span><span class="c1">// implicit quantity conversion</span>
</span><span id="__span-8-3"><a id="__codelineno-8-3" name="__codelineno-8-3" href="#__codelineno-8-3"></a><span class="n">foo</span><span class="p">(</span><span class="n">q1</span><span class="p">);</span><span class="w"> </span><span class="c1">// implicit quantity conversion</span>
</span></code></pre></div>
</li>
<li>
<p><strong>Explicit conversions</strong></p>
@ -2688,12 +2695,21 @@ the first common node in a hierarchy tree of the same kind. For example:</p>
<li>not every <em>length</em> is a <em>width</em></li>
<li>not every <em>width</em> is a <em>radius</em></li>
</ul>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-7-1"><a id="__codelineno-7-1" name="__codelineno-7-1" href="#__codelineno-7-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">));</span>
</span><span id="__span-7-2"><a id="__codelineno-7-2" name="__codelineno-7-2" href="#__codelineno-7-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">radius</span><span class="p">));</span>
</span><span id="__span-7-3"><a id="__codelineno-7-3" name="__codelineno-7-3" href="#__codelineno-7-3"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">radius</span><span class="p">));</span>
</span><span id="__span-7-4"><a id="__codelineno-7-4" name="__codelineno-7-4" href="#__codelineno-7-4"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">));</span>
</span><span id="__span-7-5"><a id="__codelineno-7-5" name="__codelineno-7-5" href="#__codelineno-7-5"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">radius</span><span class="p">));</span>
</span><span id="__span-7-6"><a id="__codelineno-7-6" name="__codelineno-7-6" href="#__codelineno-7-6"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">radius</span><span class="p">));</span>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-9-1"><a id="__codelineno-9-1" name="__codelineno-9-1" href="#__codelineno-9-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">));</span>
</span><span id="__span-9-2"><a id="__codelineno-9-2" name="__codelineno-9-2" href="#__codelineno-9-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">radius</span><span class="p">));</span>
</span><span id="__span-9-3"><a id="__codelineno-9-3" name="__codelineno-9-3" href="#__codelineno-9-3"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">radius</span><span class="p">));</span>
</span><span id="__span-9-4"><a id="__codelineno-9-4" name="__codelineno-9-4" href="#__codelineno-9-4"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">));</span>
</span><span id="__span-9-5"><a id="__codelineno-9-5" name="__codelineno-9-5" href="#__codelineno-9-5"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">radius</span><span class="p">));</span>
</span><span id="__span-9-6"><a id="__codelineno-9-6" name="__codelineno-9-6" href="#__codelineno-9-6"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">radius</span><span class="p">));</span>
</span></code></pre></div>
<p>Explicit conversions are forced by passing the quantity to a call operator of a <code>quantity_spec</code>
type or by calling <code>quantity</code>'s explicit constructor:</p>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-10-1"><a id="__codelineno-10-1" name="__codelineno-10-1" href="#__codelineno-10-1"></a><span class="kt">void</span><span class="w"> </span><span class="nf">foo</span><span class="p">(</span><span class="n">quantity</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">[</span><span class="n">m</span><span class="p">]</span><span class="o">&gt;</span><span class="w"> </span><span class="n">q</span><span class="p">);</span>
</span></code></pre></div>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-11-1"><a id="__codelineno-11-1" name="__codelineno-11-1" href="#__codelineno-11-1"></a><span class="n">quantity</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">[</span><span class="n">m</span><span class="p">]</span><span class="o">&gt;</span><span class="w"> </span><span class="n">q1</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">42</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">m</span><span class="p">;</span>
</span><span id="__span-11-2"><a id="__codelineno-11-2" name="__codelineno-11-2" href="#__codelineno-11-2"></a><span class="n">quantity</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">[</span><span class="n">m</span><span class="p">]</span><span class="o">&gt;</span><span class="w"> </span><span class="n">q2</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">(</span><span class="n">q1</span><span class="p">);</span><span class="w"> </span><span class="c1">// explicit quantity conversion</span>
</span><span id="__span-11-3"><a id="__codelineno-11-3" name="__codelineno-11-3" href="#__codelineno-11-3"></a><span class="n">quantity</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">[</span><span class="n">m</span><span class="p">]</span><span class="o">&gt;</span><span class="w"> </span><span class="n">q3</span><span class="p">(</span><span class="n">q1</span><span class="p">);</span><span class="w"> </span><span class="c1">// direct initialization</span>
</span><span id="__span-11-4"><a id="__codelineno-11-4" name="__codelineno-11-4" href="#__codelineno-11-4"></a><span class="n">foo</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">(</span><span class="n">q1</span><span class="p">));</span><span class="w"> </span><span class="c1">// explicit quantity conversion</span>
</span></code></pre></div>
</li>
<li>
@ -2702,9 +2718,16 @@ the first common node in a hierarchy tree of the same kind. For example:</p>
<li><em>height</em> is not a <em>width</em></li>
<li>both <em>height</em> and <em>width</em> are quantities of kind <em>length</em></li>
</ul>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-8-1"><a id="__codelineno-8-1" name="__codelineno-8-1" href="#__codelineno-8-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">));</span>
</span><span id="__span-8-2"><a id="__codelineno-8-2" name="__codelineno-8-2" href="#__codelineno-8-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">));</span>
</span><span id="__span-8-3"><a id="__codelineno-8-3" name="__codelineno-8-3" href="#__codelineno-8-3"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">castable</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">));</span>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-12-1"><a id="__codelineno-12-1" name="__codelineno-12-1" href="#__codelineno-12-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">));</span>
</span><span id="__span-12-2"><a id="__codelineno-12-2" name="__codelineno-12-2" href="#__codelineno-12-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">));</span>
</span><span id="__span-12-3"><a id="__codelineno-12-3" name="__codelineno-12-3" href="#__codelineno-12-3"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">castable</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">));</span>
</span></code></pre></div>
<p>Explicit casts are forced with a dedicated <code>quantity_cast</code> function:</p>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-13-1"><a id="__codelineno-13-1" name="__codelineno-13-1" href="#__codelineno-13-1"></a><span class="kt">void</span><span class="w"> </span><span class="nf">foo</span><span class="p">(</span><span class="n">quantity</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">[</span><span class="n">m</span><span class="p">]</span><span class="o">&gt;</span><span class="w"> </span><span class="n">q</span><span class="p">);</span>
</span></code></pre></div>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-14-1"><a id="__codelineno-14-1" name="__codelineno-14-1" href="#__codelineno-14-1"></a><span class="n">quantity</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">[</span><span class="n">m</span><span class="p">]</span><span class="o">&gt;</span><span class="w"> </span><span class="n">q1</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">42</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">m</span><span class="p">;</span>
</span><span id="__span-14-2"><a id="__codelineno-14-2" name="__codelineno-14-2" href="#__codelineno-14-2"></a><span class="n">quantity</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">[</span><span class="n">m</span><span class="p">]</span><span class="o">&gt;</span><span class="w"> </span><span class="n">q2</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">quantity_cast</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="o">&gt;</span><span class="p">(</span><span class="n">q1</span><span class="p">);</span><span class="w"> </span><span class="c1">// explicit quantity cast</span>
</span><span id="__span-14-3"><a id="__codelineno-14-3" name="__codelineno-14-3" href="#__codelineno-14-3"></a><span class="n">foo</span><span class="p">(</span><span class="n">quantity_cast</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="o">&gt;</span><span class="p">(</span><span class="n">q1</span><span class="p">));</span><span class="w"> </span><span class="c1">// explicit quantity cast</span>
</span></code></pre></div>
</li>
<li>
@ -2712,9 +2735,15 @@ the first common node in a hierarchy tree of the same kind. For example:</p>
<ul>
<li><em>time</em> has nothing in common with <em>length</em></li>
</ul>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-9-1"><a id="__codelineno-9-1" name="__codelineno-9-1" href="#__codelineno-9-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">));</span>
</span><span id="__span-9-2"><a id="__codelineno-9-2" name="__codelineno-9-2" href="#__codelineno-9-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">));</span>
</span><span id="__span-9-3"><a id="__codelineno-9-3" name="__codelineno-9-3" href="#__codelineno-9-3"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">castable</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">));</span>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-15-1"><a id="__codelineno-15-1" name="__codelineno-15-1" href="#__codelineno-15-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">));</span>
</span><span id="__span-15-2"><a id="__codelineno-15-2" name="__codelineno-15-2" href="#__codelineno-15-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">));</span>
</span><span id="__span-15-3"><a id="__codelineno-15-3" name="__codelineno-15-3" href="#__codelineno-15-3"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">castable</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">));</span>
</span></code></pre></div>
<p>Even the explicit casts will not force such a conversion:</p>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-16-1"><a id="__codelineno-16-1" name="__codelineno-16-1" href="#__codelineno-16-1"></a><span class="kt">void</span><span class="w"> </span><span class="nf">foo</span><span class="p">(</span><span class="n">quantity</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">[</span><span class="n">m</span><span class="p">]</span><span class="o">&gt;</span><span class="p">);</span>
</span></code></pre></div>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-17-1"><a id="__codelineno-17-1" name="__codelineno-17-1" href="#__codelineno-17-1"></a><span class="n">quantity</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">[</span><span class="n">m</span><span class="p">]</span><span class="o">&gt;</span><span class="w"> </span><span class="n">q1</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">42</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">s</span><span class="p">;</span><span class="w"> </span><span class="c1">// Compile-time error</span>
</span><span id="__span-17-2"><a id="__codelineno-17-2" name="__codelineno-17-2" href="#__codelineno-17-2"></a><span class="n">foo</span><span class="p">(</span><span class="n">quantity_cast</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="o">&gt;</span><span class="p">(</span><span class="mi">42</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">s</span><span class="p">));</span><span class="w"> </span><span class="c1">// Compile-time error</span>
</span></code></pre></div>
</li>
</ol>
@ -2747,20 +2776,20 @@ that can be used to create them implicitly:</p>
and <em>time</em>. As those are also the roots of quantities of their kinds and all other quantities from their
trees are implicitly convertible to them (we agreed on that "every <em>width</em> is a <em>length</em>" already),
it means that an <em>energy</em> can be implicitly constructed from any quantity of <em>mass</em>, <em>length</em>, and <em>time</em>:</p>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-10-1"><a id="__codelineno-10-1" name="__codelineno-10-1" href="#__codelineno-10-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">mass</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">)</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">),</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">energy</span><span class="p">));</span>
</span><span id="__span-10-2"><a id="__codelineno-10-2" name="__codelineno-10-2" href="#__codelineno-10-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">mass</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">)</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">),</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">energy</span><span class="p">));</span>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-18-1"><a id="__codelineno-18-1" name="__codelineno-18-1" href="#__codelineno-18-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">mass</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">)</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">),</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">energy</span><span class="p">));</span>
</span><span id="__span-18-2"><a id="__codelineno-18-2" name="__codelineno-18-2" href="#__codelineno-18-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">mass</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">)</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">),</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">energy</span><span class="p">));</span>
</span></code></pre></div>
</li>
<li>
<p><em>mechanical energy</em> is a more "specialized" quantity than <em>energy</em> (not every <em>energy</em> is
a <em>mechanical energy</em>). It is why an explicit cast is needed to convert from either <em>energy</em> or
the results of its <a href="../../../appendix/glossary/#quantity-equation">quantity equation</a>:</p>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-11-1"><a id="__codelineno-11-1" name="__codelineno-11-1" href="#__codelineno-11-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">energy</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">mechanical_energy</span><span class="p">));</span>
</span><span id="__span-11-2"><a id="__codelineno-11-2" name="__codelineno-11-2" href="#__codelineno-11-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">energy</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">mechanical_energy</span><span class="p">));</span>
</span><span id="__span-11-3"><a id="__codelineno-11-3" name="__codelineno-11-3" href="#__codelineno-11-3"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">mass</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">)</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">),</span>
</span><span id="__span-11-4"><a id="__codelineno-11-4" name="__codelineno-11-4" href="#__codelineno-11-4"></a><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">mechanical_energy</span><span class="p">));</span>
</span><span id="__span-11-5"><a id="__codelineno-11-5" name="__codelineno-11-5" href="#__codelineno-11-5"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">mass</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">)</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">),</span>
</span><span id="__span-11-6"><a id="__codelineno-11-6" name="__codelineno-11-6" href="#__codelineno-11-6"></a><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">mechanical_energy</span><span class="p">));</span>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-19-1"><a id="__codelineno-19-1" name="__codelineno-19-1" href="#__codelineno-19-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">energy</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">mechanical_energy</span><span class="p">));</span>
</span><span id="__span-19-2"><a id="__codelineno-19-2" name="__codelineno-19-2" href="#__codelineno-19-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">energy</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">mechanical_energy</span><span class="p">));</span>
</span><span id="__span-19-3"><a id="__codelineno-19-3" name="__codelineno-19-3" href="#__codelineno-19-3"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">mass</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">)</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">),</span>
</span><span id="__span-19-4"><a id="__codelineno-19-4" name="__codelineno-19-4" href="#__codelineno-19-4"></a><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">mechanical_energy</span><span class="p">));</span>
</span><span id="__span-19-5"><a id="__codelineno-19-5" name="__codelineno-19-5" href="#__codelineno-19-5"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">mass</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">)</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">),</span>
</span><span id="__span-19-6"><a id="__codelineno-19-6" name="__codelineno-19-6" href="#__codelineno-19-6"></a><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">mechanical_energy</span><span class="p">));</span>
</span></code></pre></div>
</li>
<li>
@ -2769,14 +2798,14 @@ that can be used to create them implicitly:</p>
<a href="../../../appendix/glossary/#quantity-equation">quantity equation</a>. Maybe not every
<code>mass * pow&lt;2&gt;(length) / pow&lt;2&gt;(time)</code> is a <em>gravitational potential energy</em>, but every
<code>mass * acceleration_of_free_fall * height</code> is.</p>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-12-1"><a id="__codelineno-12-1" name="__codelineno-12-1" href="#__codelineno-12-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">energy</span><span class="p">,</span><span class="w"> </span><span class="n">gravitational_potential_energy</span><span class="p">));</span>
</span><span id="__span-12-2"><a id="__codelineno-12-2" name="__codelineno-12-2" href="#__codelineno-12-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">energy</span><span class="p">,</span><span class="w"> </span><span class="n">gravitational_potential_energy</span><span class="p">));</span>
</span><span id="__span-12-3"><a id="__codelineno-12-3" name="__codelineno-12-3" href="#__codelineno-12-3"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">mass</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">)</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">),</span>
</span><span id="__span-12-4"><a id="__codelineno-12-4" name="__codelineno-12-4" href="#__codelineno-12-4"></a><span class="w"> </span><span class="n">gravitational_potential_energy</span><span class="p">));</span>
</span><span id="__span-12-5"><a id="__codelineno-12-5" name="__codelineno-12-5" href="#__codelineno-12-5"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">mass</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">)</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">),</span>
</span><span id="__span-12-6"><a id="__codelineno-12-6" name="__codelineno-12-6" href="#__codelineno-12-6"></a><span class="w"> </span><span class="n">gravitational_potential_energy</span><span class="p">));</span>
</span><span id="__span-12-7"><a id="__codelineno-12-7" name="__codelineno-12-7" href="#__codelineno-12-7"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">mass</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">acceleration_of_free_fall</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">,</span>
</span><span id="__span-12-8"><a id="__codelineno-12-8" name="__codelineno-12-8" href="#__codelineno-12-8"></a><span class="w"> </span><span class="n">gravitational_potential_energy</span><span class="p">));</span>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-20-1"><a id="__codelineno-20-1" name="__codelineno-20-1" href="#__codelineno-20-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">energy</span><span class="p">,</span><span class="w"> </span><span class="n">gravitational_potential_energy</span><span class="p">));</span>
</span><span id="__span-20-2"><a id="__codelineno-20-2" name="__codelineno-20-2" href="#__codelineno-20-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">energy</span><span class="p">,</span><span class="w"> </span><span class="n">gravitational_potential_energy</span><span class="p">));</span>
</span><span id="__span-20-3"><a id="__codelineno-20-3" name="__codelineno-20-3" href="#__codelineno-20-3"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">mass</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">)</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">),</span>
</span><span id="__span-20-4"><a id="__codelineno-20-4" name="__codelineno-20-4" href="#__codelineno-20-4"></a><span class="w"> </span><span class="n">gravitational_potential_energy</span><span class="p">));</span>
</span><span id="__span-20-5"><a id="__codelineno-20-5" name="__codelineno-20-5" href="#__codelineno-20-5"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">explicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">mass</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">)</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">pow</span><span class="o">&lt;</span><span class="mi">2</span><span class="o">&gt;</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">),</span>
</span><span id="__span-20-6"><a id="__codelineno-20-6" name="__codelineno-20-6" href="#__codelineno-20-6"></a><span class="w"> </span><span class="n">gravitational_potential_energy</span><span class="p">));</span>
</span><span id="__span-20-7"><a id="__codelineno-20-7" name="__codelineno-20-7" href="#__codelineno-20-7"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">mass</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">acceleration_of_free_fall</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">,</span>
</span><span id="__span-20-8"><a id="__codelineno-20-8" name="__codelineno-20-8" href="#__codelineno-20-8"></a><span class="w"> </span><span class="n">gravitational_potential_energy</span><span class="p">));</span>
</span></code></pre></div>
</li>
</ul>
@ -2793,16 +2822,16 @@ to type <code>kind_of&lt;isq::length&gt;</code>.</p>
</div>
<p>Such an entity behaves as any quantity of its kind. This means that it is implicitly
convertible to any quantity in a tree.</p>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-13-1"><a id="__codelineno-13-1" name="__codelineno-13-1" href="#__codelineno-13-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">));</span>
</span><span id="__span-13-2"><a id="__codelineno-13-2" name="__codelineno-13-2" href="#__codelineno-13-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">kind_of</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="o">&gt;</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">));</span>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-21-1"><a id="__codelineno-21-1" name="__codelineno-21-1" href="#__codelineno-21-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">));</span>
</span><span id="__span-21-2"><a id="__codelineno-21-2" name="__codelineno-21-2" href="#__codelineno-21-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">implicitly_convertible</span><span class="p">(</span><span class="n">kind_of</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="o">&gt;</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">height</span><span class="p">));</span>
</span></code></pre></div>
<p>Additionally, the result of operations on quantity kinds is also a quantity kind:</p>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-14-1"><a id="__codelineno-14-1" name="__codelineno-14-1" href="#__codelineno-14-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">same_type</span><span class="o">&lt;</span><span class="n">kind_of</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="o">&gt;</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">kind_of</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="o">&gt;</span><span class="p">,</span><span class="w"> </span><span class="n">kind_of</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="o">&gt;&gt;</span><span class="p">);</span>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-22-1"><a id="__codelineno-22-1" name="__codelineno-22-1" href="#__codelineno-22-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">same_type</span><span class="o">&lt;</span><span class="n">kind_of</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="o">&gt;</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">kind_of</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="o">&gt;</span><span class="p">,</span><span class="w"> </span><span class="n">kind_of</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="o">&gt;&gt;</span><span class="p">);</span>
</span></code></pre></div>
<p>However, if at least one equation's operand is not a quantity kind, the result becomes a "strong"
quantity where all the kinds are converted to the hierarchy tree's root quantities:</p>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-15-1"><a id="__codelineno-15-1" name="__codelineno-15-1" href="#__codelineno-15-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">same_type</span><span class="o">&lt;</span><span class="n">kind_of</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="o">&gt;</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">,</span><span class="w"> </span><span class="n">kind_of</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="o">&gt;&gt;</span><span class="p">);</span>
</span><span id="__span-15-2"><a id="__codelineno-15-2" name="__codelineno-15-2" href="#__codelineno-15-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">same_type</span><span class="o">&lt;</span><span class="n">kind_of</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="o">&gt;</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="o">&gt;</span><span class="p">);</span>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-23-1"><a id="__codelineno-23-1" name="__codelineno-23-1" href="#__codelineno-23-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="o">!</span><span class="n">same_type</span><span class="o">&lt;</span><span class="n">kind_of</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="o">&gt;</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">,</span><span class="w"> </span><span class="n">kind_of</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="o">&gt;&gt;</span><span class="p">);</span>
</span><span id="__span-23-2"><a id="__codelineno-23-2" name="__codelineno-23-2" href="#__codelineno-23-2"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">same_type</span><span class="o">&lt;</span><span class="n">kind_of</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="o">&gt;</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="p">,</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="w"> </span><span class="o">/</span><span class="w"> </span><span class="n">isq</span><span class="o">::</span><span class="n">time</span><span class="o">&gt;</span><span class="p">);</span>
</span></code></pre></div>
<div class="admonition info">
<p class="admonition-title">Info</p>
@ -2810,7 +2839,7 @@ quantity where all the kinds are converted to the hierarchy tree's root quantiti
in the <code>quantity_spec</code> definition can be put as a template parameter to the <code>kind_of</code>
specifier. For example, <code>kind_of&lt;isq::width&gt;</code> will fail to compile. However, we can call
<code>get_kind(q)</code> to obtain a kind of any quantity:</p>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-16-1"><a id="__codelineno-16-1" name="__codelineno-16-1" href="#__codelineno-16-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">get_kind</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">)</span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="n">kind_of</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="o">&gt;</span><span class="p">);</span>
<div class="language-cpp highlight"><pre><span></span><code><span id="__span-24-1"><a id="__codelineno-24-1" name="__codelineno-24-1" href="#__codelineno-24-1"></a><span class="k">static_assert</span><span class="p">(</span><span class="n">get_kind</span><span class="p">(</span><span class="n">isq</span><span class="o">::</span><span class="n">width</span><span class="p">)</span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="n">kind_of</span><span class="o">&lt;</span><span class="n">isq</span><span class="o">::</span><span class="n">length</span><span class="o">&gt;</span><span class="p">);</span>
</span></code></pre></div>
</div>