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>
2.7 KiB
nlohmann::basic_json_view::materialize
BasicJsonType materialize() const;
Builds the BasicJsonType value of this subtree: the value BasicJsonType::parse() would
have produced for the same source text, allocated for the first time by this call.
Return value
The BasicJsonType value of this subtree, or a discarded BasicJsonType value (#!cpp BasicJsonType(value_t::discarded))
if the view is discarded.
Exception safety
Strong guarantee: there are no changes to the view or the document it refers to (nothing about either is mutated by this function).
Exceptions
May throw #!cpp std::bad_alloc (via BasicJsonType's allocator) if constructing the result fails.
Complexity
Linear in the size of the subtree.
Notes
materialize() replays the subtree through the same SAX builder BasicJsonType::parse()
uses, so the result matches it exactly — including, for an object, that a repeated key keeps only its
last value. The replay is iterative, so it is not limited by the call stack the way a naive recursive conversion
would be; the JSON nesting depth is limited only by available memory, as for BasicJsonType::parse() itself.
Unlike parsing with JSON_DIAGNOSTIC_POSITIONS enabled, the values
produced by materialize() do not carry source positions. The index has the start offset of every value, but not the
end of arrays, objects, and escaped strings, which the positions also need.
Calling materialize() on the same view repeatedly builds a new, independent BasicJsonType value each time; it
never caches the result.
Examples
??? example
The example below skips messages that are not useful — a discarded value, or an empty array — using only
[`is_array()`](is_array.md) and [`empty()`](empty.md), and calls `materialize()` only for the messages that are
actually used, so no `BasicJsonType` value (and none of its per-element allocations) is ever built for the
skipped ones.
```cpp
--8<-- "examples/basic_json_view__materialize.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__materialize.output"
```
See also
root- the view of a document's root valueBasicJsonType::parse- build aBasicJsonTypevalue directly from a JSON textJSON_DIAGNOSTIC_POSITIONS- source positions on parsed values (not produced bymaterialize())- Zero-copy JSON views - when to build a basic_json value from a view
Version history
- Added in version 3.13.0.