deploy: 54f6b3ef06

features/json_patch/index.html

@@ -46,7 +46,7 @@
     S["source"] -->|"diff(source, target)"| P["patch"]
     S -->|"source.patch(patch)"| T["target"]
     P -.-&gt;|"applied to source, yields"| T</code></pre> <p class=nj-caption>How <code>diff</code> and <code>patch</code> relate: <code>diff(source, target)</code> yields a patch, and applying that patch to the source yields the target.</p> <div class="admonition success"> <p class=admonition-title>Invariant</p> <p>For two <abbr title="JavaScript Object Notation">JSON</abbr> values <em>source</em> and <em>target</em>, the following code yields true:</p> <div class=highlight><pre><span></span><code><span class=n>source</span><span class=p>.</span><span class=n>patch</span><span class=p>(</span><span class=n>diff</span><span class=p>(</span><span class=n>source</span><span class=p>,</span><span class=w> </span><span class=n>target</span><span class=p>))</span><span class=w> </span><span class=o>==</span><span class=w> </span><span class=n>target</span><span class=p>;</span>
-</code></pre></div> <p>The equality holds up to <a href=../../api/basic_json/operator_eq/ ><code>operator==</code></a>, with these exceptions:</p> <ul> <li><code>NaN</code> and <a href=../../api/basic_json/is_discarded/ >discarded</a> values are not equal to themselves, so the invariant cannot hold for them. <code>diff</code> emits a <code>replace</code> operation for such a value, and a <code>NaN</code> in a patch is serialized as <code class=highlight><span class=kc>null</span></code>.</li> <li>Numbers that compare equal produce no operation even if their types differ: <code>diff(1, 1.0)</code>, <code>diff(1u, 1)</code>, and <code>diff(0.0, -0.0)</code> return <code class=highlight><span class=p>[]</span></code>, so the patched value keeps the number type of <em>source</em>.</li> <li>A <a href=../binary_values/ >binary value</a> in a patch is serialized as an object (<code class=highlight><span class=p>{</span><span class=nt>"bytes"</span><span class=p>:[</span><span class=err>...</span><span class=p>],</span><span class=nt>"subtype"</span><span class=p>:</span><span class=kc>null</span><span class=p>}</span></code>), so a patch that was dumped and parsed again no longer holds a binary value.</li> </ul> </div> <details class=example> <summary>Example: create a <abbr title="JavaScript Object Notation">JSON</abbr> Patch from the difference of two values</summary> <p>The following code shows how a <abbr title="JavaScript Object Notation">JSON</abbr> patch is created as a diff for two <abbr title="JavaScript Object Notation">JSON</abbr> values.</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
+</code></pre></div> <p>The equality holds up to <a href=../../api/basic_json/operator_eq/ ><code>operator==</code></a>, with these exceptions:</p> <ul> <li><code>NaN</code> and <a href=../../api/basic_json/is_discarded/ >discarded</a> values are not equal to themselves, so the invariant cannot hold for them. <code>diff</code> emits a <code>replace</code> operation for such a value, and a <code>NaN</code> in a patch is serialized as <code class=highlight><span class=kc>null</span></code>.</li> <li>Numbers that compare equal produce no operation even if their types differ or if one is zero and the other is negative zero: <code>diff(1, 1.0)</code>, <code>diff(1u, 1)</code>, and <code>diff(0.0, -0.0)</code> return <code class=highlight><span class=p>[]</span></code>, so the patched value keeps the number type and sign of <em>source</em>.</li> <li>A <a href=../binary_values/ >binary value</a> in a patch is serialized as an object (<code class=highlight><span class=p>{</span><span class=nt>"bytes"</span><span class=p>:[</span><span class=err>...</span><span class=p>],</span><span class=nt>"subtype"</span><span class=p>:</span><span class=kc>null</span><span class=p>}</span></code>), so a patch that was dumped and parsed again no longer holds a binary value.</li> </ul> </div> <details class=example> <summary>Example: create a <abbr title="JavaScript Object Notation">JSON</abbr> Patch from the difference of two values</summary> <p>The following code shows how a <abbr title="JavaScript Object Notation">JSON</abbr> patch is created as a diff for two <abbr title="JavaScript Object Notation">JSON</abbr> values.</p> <div class=highlight><pre><span></span><code><span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iostream&gt;</span>
 <span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;iomanip&gt;</span>
 <span class=cp>#include</span><span class=w> </span><span class=cpf>&lt;nlohmann/json.hpp&gt;</span>
 
@@ -108,4 +108,4 @@
 <span class=w>        </span><span class=s2>"world"</span>
 <span class=w>    </span><span class=p>]</span>
 <span class=p>}</span>
-</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../json_pointer/ ><abbr title="JavaScript Object Notation">JSON</abbr> Pointer</a> - the addressing scheme used for patch paths</li> <li><a href=../merge_patch/ ><abbr title="JavaScript Object Notation">JSON</abbr> Merge Patch</a> - a simpler, less expressive alternative patch format</li> <li><a href=../../api/basic_json/patch/ ><code>patch</code></a> - apply a <abbr title="JavaScript Object Notation">JSON</abbr> Patch, returning the result as a copy</li> <li><a href=../../api/basic_json/patch_inplace/ ><code>patch_inplace</code></a> - apply a <abbr title="JavaScript Object Notation">JSON</abbr> Patch without copying</li> <li><a href=../../api/basic_json/diff/ ><code>diff</code></a> - compute a <abbr title="JavaScript Object Notation">JSON</abbr> Patch from two values</li> <li><a href=../../api/json_pointer/ ><code>json_pointer</code></a> - type to represent <abbr title="JavaScript Object Notation">JSON</abbr> Pointers</li> <li><a href=../../api/basic_json/merge_diff/ ><code>merge_diff</code></a> - compute a <abbr title="JavaScript Object Notation">JSON</abbr> Merge Patch from two values</li> <li><a href=../modifying_values/ >Modifying values</a> - simple in-place modifications</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="October 27, 2026 06:41:42 UTC">October 27, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <nav class="md-footer__inner md-grid" aria-label=Footer> <a href=../merge_patch/ class="md-footer__link md-footer__link--prev" aria-label="Previous: JSON Merge Patch"> <div class="md-footer__button md-icon"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M20 11v2H8l5.5 5.5-1.42 1.42L4.16 12l7.92-7.92L13.5 5.5 8 11z"/></svg> </div> <div class=md-footer__title> <span class=md-footer__direction> Previous </span> <div class=md-ellipsis> JSON Merge Patch </div> </div> </a> <a href=../json_pointer/ class="md-footer__link md-footer__link--next" aria-label="Next: JSON Pointer"> <div class=md-footer__title> <span class=md-footer__direction> Next </span> <div class=md-ellipsis> JSON Pointer </div> </div> <div class="md-footer__button md-icon"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M4 11v2h12l-5.5 5.5 1.42 1.42L19.84 12l-7.92-7.92L10.5 5.5 16 11z"/></svg> </div> </a> </nav> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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+</code></pre></div> </details> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">&para;</a></h2> <ul> <li><a href=../json_pointer/ ><abbr title="JavaScript Object Notation">JSON</abbr> Pointer</a> - the addressing scheme used for patch paths</li> <li><a href=../merge_patch/ ><abbr title="JavaScript Object Notation">JSON</abbr> Merge Patch</a> - a simpler, less expressive alternative patch format</li> <li><a href=../../api/basic_json/patch/ ><code>patch</code></a> - apply a <abbr title="JavaScript Object Notation">JSON</abbr> Patch, returning the result as a copy</li> <li><a href=../../api/basic_json/patch_inplace/ ><code>patch_inplace</code></a> - apply a <abbr title="JavaScript Object Notation">JSON</abbr> Patch without copying</li> <li><a href=../../api/basic_json/diff/ ><code>diff</code></a> - compute a <abbr title="JavaScript Object Notation">JSON</abbr> Patch from two values</li> <li><a href=../../api/json_pointer/ ><code>json_pointer</code></a> - type to represent <abbr title="JavaScript Object Notation">JSON</abbr> Pointers</li> <li><a href=../../api/basic_json/merge_diff/ ><code>merge_diff</code></a> - compute a <abbr title="JavaScript Object Notation">JSON</abbr> Merge Patch from two values</li> <li><a href=../modifying_values/ >Modifying values</a> - simple in-place modifications</li> </ul> <!-- https://squidfunk.github.io/mkdocs-material/reference/tooltips/#adding-a-glossary --> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date" title="October 27, 2026 16:16:08 UTC">October 27, 2026</span> </span> </aside> </article> </div> <script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var labels=set.querySelector(".tabbed-labels");for(var tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script> <script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script> </div> <button type=button class="md-top md-icon" data-md-component=top hidden> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8z"/></svg> Back to top </button> </main> <footer class=md-footer> <nav class="md-footer__inner md-grid" aria-label=Footer> <a href=../merge_patch/ class="md-footer__link md-footer__link--prev" aria-label="Previous: JSON Merge Patch"> <div class="md-footer__button md-icon"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M20 11v2H8l5.5 5.5-1.42 1.42L4.16 12l7.92-7.92L13.5 5.5 8 11z"/></svg> </div> <div class=md-footer__title> <span class=md-footer__direction> Previous </span> <div class=md-ellipsis> JSON Merge Patch </div> </div> </a> <a href=../json_pointer/ class="md-footer__link md-footer__link--next" aria-label="Next: JSON Pointer"> <div class=md-footer__title> <span class=md-footer__direction> Next </span> <div class=md-ellipsis> JSON Pointer </div> </div> <div class="md-footer__button md-icon"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M4 11v2h12l-5.5 5.5 1.42 1.42L19.84 12l-7.92-7.92L10.5 5.5 16 11z"/></svg> </div> </a> </nav> <div class="md-footer-meta md-typeset"> <div class="md-footer-meta__inner md-grid"> <div class=md-copyright> <div class=md-copyright__highlight> Copyright &copy; 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features/json_patch/index.md

@@ -105,7 +105,7 @@ source.patch(diff(source, target)) == target;
 The equality holds up to [`operator==`](https://json.nlohmann.me/api/basic_json/operator_eq/index.md), with these exceptions:
 
 - `NaN` and [discarded](https://json.nlohmann.me/api/basic_json/is_discarded/index.md) values are not equal to themselves, so the invariant cannot hold for them. `diff` emits a `replace` operation for such a value, and a `NaN` in a patch is serialized as `null`.
-- Numbers that compare equal produce no operation even if their types differ: `diff(1, 1.0)`, `diff(1u, 1)`, and `diff(0.0, -0.0)` return `[]`, so the patched value keeps the number type of *source*.
+- Numbers that compare equal produce no operation even if their types differ or if one is zero and the other is negative zero: `diff(1, 1.0)`, `diff(1u, 1)`, and `diff(0.0, -0.0)` return `[]`, so the patched value keeps the number type and sign of *source*.
 - A [binary value](https://json.nlohmann.me/features/binary_values/index.md) in a patch is serialized as an object (`{"bytes":[...],"subtype":null}`), so a patch that was dumped and parsed again no longer holds a binary value.
 
 Example: create a JSON Patch from the difference of two values