Niels Lohmann
a47170346a
* docs: new design for the documentation site Apply the brand to the Material for MkDocs site: Inter and JetBrains Mono served by the site (upright and real italic), brand colours, blue header band with the syntax pattern, wordmark in the header, new home page (hero, cards, animated feature tour), 404 page, polish for tabs, search, footer, focus rings, tables and code blocks, and theme features (code copy, previous/next footer, TOC follow, search suggestions). Draw the number railroad diagram, the parser callback events and the iterator illustrations as inline SVGs that follow the light and dark scheme. The generator scripts are in docs/mkdocs/scripts/figures; the feature slideshow (json-light.svg, json-dark.svg, replacing json.gif on the home page) is built by docs/mkdocs/scripts/slideshow. Decision nodes in five flowcharts become hexagons, which need far less room. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * docs: add figures, table captions and a macro chooser - Figures with numbered captions: SAX stepper, json_view layout and edit stepper, exception map, JSON pointer and patch walkers, QA pipeline, scaling and binary size charts, roadmap lanes, release timeline, integration decision tree and namespace builder - Table captions (nj-table-caption) on 9 pages - Compile times: modules and PCH charts, filesystem section, re-measured Figure 1, links between features/modules.md and compile_times.md - Interactive macro chooser for features/arbitrary_types.md - Link check: exclude URLs that answer the plugin with 400/401/419 or are dead (customers.md) Signed-off-by: Niels Lohmann <mail@nlohmann.me> * docs: macro chooser generates adl_serializer for non-default-constructible types Signed-off-by: Niels Lohmann <mail@nlohmann.me> * docs: cross-link concept pages and API pages in See also sections Add See also links in both directions between the concept pages (features, home, integration) and the API pages, write API links in code font, give every entry a comment after a dash, and show the callback event figure on the parser callbacks page. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * docs: address review comments on the new design - Home: add a "Latest release" button - Sponsors: update the list and group it by tier - Features: list all feature pages on the index page - Releases: add highlights per release, link the 4.0 roadmap, add the first commit to the timeline - Exceptions: prefix all example messages with the exception name - API: no code font for format names in the See also links of the to_/from_ pages - Merge Patch: show the document before, the patch, and the result - Replace "--" with typographic dashes, mark external links with an icon, center Mermaid diagrams Signed-off-by: Niels Lohmann <mail@nlohmann.me> --------- Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2.0 KiB
2.0 KiB
nlohmann::basic_json::emplace_back
template<class... Args>
reference emplace_back(Args&& ... args);
Creates a JSON value from the passed parameters args to the end of the JSON value. If the function is called on a JSON
#!json null value, an empty array is created before appending the value created from args.
Template parameters
Args- compatible types to create a
basic_jsonobject
Iterator invalidation
By adding an element to the end of the array, a reallocation can happen, in which case all iterators (including the
end() iterator) and all references to the elements are invalidated. Otherwise, only the end()
iterator is invalidated.
Parameters
args(in)- arguments to forward to a constructor of
basic_json
Return value
reference to the inserted element
Exception safety
Strong guarantee: if an exception is thrown, there are no changes to any JSON value. As an exception, a #!json null
value is converted to an empty array before the element is added and keeps that type if adding the element throws.
Exceptions
Throws type_error.311 when called on a type other than JSON
array or #!json null; example: "cannot use emplace_back() with number"
Complexity
Amortized constant.
Examples
??? example
The example shows how `emplace_back()` can be used to add elements to a JSON array. Note how the `null` value was
silently converted to a JSON array.
```cpp
--8<-- "examples/emplace_back.cpp"
```
Output:
```json
--8<-- "examples/emplace_back.output"
```
See also
operator+=- add a value to an array/objectpush_back- add a value to an array/object- Modifying values - the article on modifying values
Version history
- Added in version 2.0.8.
- Returns reference since 3.7.0.