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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::get_ref
template<typename ReferenceType>
ReferenceType get_ref();
template<typename ReferenceType>
const ReferenceType get_ref() const;
Implicit reference access to the internally stored JSON value. No copies are made.
Template parameters
ReferenceType- reference type; must be a reference to
array_t,object_t,string_t,boolean_t,number_integer_t, ornumber_unsigned_t,number_float_t, orbinary_t. Enforced by a static assertion.
Return value
reference to the internally stored JSON value if the requested reference type fits to the JSON value; throws
type_error.303 otherwise
Exception safety
Strong exception safety: if an exception occurs, the original value stays intact.
Exceptions
Throws type_error.303 if the requested reference type does not
match the stored JSON value type; example: "incompatible ReferenceType for get_ref, actual type is binary".
Complexity
Constant.
Notes
!!! danger "Undefined behavior"
The reference becomes invalid if the underlying JSON object changes.
Examples
??? example
The example shows several calls to `get_ref()`.
```cpp
--8<-- "examples/get_ref.cpp"
```
Output:
```json
--8<-- "examples/get_ref.output"
```
See also
get_ptr()- get a pointer valuebasic_json_view::get_string- the closest counterpart on a zero-copy view: a string without a copy, but as a view rather than a reference to a value that must already exist- Converting values - getting values out, with or without copying
Version history
- Added in version 1.1.0.
- Extended to binary types in version 3.8.0.