Files
json/docs/mkdocs/docs/examples/basic_json_document__insert.cpp
T
Niels Lohmann 330fbead59 Document clang-tidy exclusions, drop unneeded ones, and clean up doc examples (#5909)
* Document clang-tidy exclusions and drop unneeded ones

Re-enable every excluded check in a run of clang-tidy 22 over all tests
and remove the seven that never fire (cert-err58-cpp,
clang-analyzer-webkit.NoUncountedMemberChecker,
cppcoreguidelines-virtual-class-destructor, google-readability-function-size,
hicpp-function-size, hicpp-no-assembler, readability-function-size).

Document the reason for every remaining exclusion at the top of the file.

Exclude in advance the checks that only exist in clang-tidy 23 and are
noise here (bugprone-signed-bitwise, *-explicit-constructor,
readability-trailing-comma, modernize-use-string-view), plus
modernize-use-integer-sign-comparison, which needs C++20 std::cmp_less
and flags deliberate casts.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix clang-tidy findings in documentation examples and replace redundant aliases

Apply clang-tidy fixes to the documentation examples:
- performance-avoid-endl: std::endl -> '\n'
- readability-qualified-auto: auto -> auto* / const auto*
- performance-for-range-copy: copy -> const reference
- google-readability-casting: C-style cast -> static_cast

Replace redundant aliases (readability-redundant-qualified-alias) such as
"using json = nlohmann::json;" with "using nlohmann::json;" in the
documentation, README, examples, tests, and benchmarks. Aliases at class
scope and aliases of other types (with_base_class_t etc.) are kept.

No changes to the library or its public API. All changed examples were
compiled and run; their output matches the stored .output files (except
max_size and meta, which depend on the platform and compiler).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Format doc examples with the pinned astyle

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-25 12:07:51 +01:00

39 lines
1.4 KiB
C++

#include <iostream>
#include <nlohmann/json_view.hpp>
using nlohmann::json;
using nlohmann::json_editable_document;
using nlohmann::json_editable_view;
int main()
{
// a deployment plan -- "budget" is written with a trailing zero that has
// no effect on its value
const std::string text = R"({
"release": "2026.09",
"steps": ["build", "test", "deploy"],
"budget": 19.90
})";
json_editable_document doc = json_editable_document::parse(text);
const std::size_t deploy_index = 2;
const auto deploy = doc.root()["steps"][deploy_index]; // held across the insert
doc.insert(doc.root()["steps"], deploy_index, "smoke-test"); // insert before "deploy"
// the held view still refers to "deploy", even though its index moved
// from 2 to 3, and nothing else in the document was touched
std::cout << deploy.dump() << '\n';
std::cout << doc.root().dump(2, ' ', false, json_editable_view::number_format::source) << "\n\n";
// the same edit on a plain json value: an index held from before the
// insert now refers to whatever moved into that slot, and dump()
// rewrites "budget" to its shortest form even though it was never
// touched
json plain = json::parse(text);
plain["steps"].insert(plain["steps"].begin() + static_cast<std::ptrdiff_t>(deploy_index), "smoke-test");
std::cout << plain["steps"][deploy_index].dump() << '\n';
std::cout << plain.dump(2) << '\n';
}