* Add element access, iteration, values, and JSON pointers to json_view
Give basic_json_view the read-only access functions of basic_json:
operator[] and at() with keys and indices, front()/back(), find(),
contains(), count(), begin()/end() and cbegin()/cend(), items()
with structured bindings from C++17 on, and type_name().
Exceptions have the ids and messages of the const functions of
basic_json. Where basic_json has undefined behavior the view
answers safely: operator[] with a missing key or an out-of-range
index returns a discarded view, and front()/back() of an empty
container throw invalid_iterator.214. Objects are iterated in
document order, and all members are visited; duplicate-key lookups
find the first member (as yyjson and simdjson do), while parse(),
materialize(), and the map conversions keep the last value, as
parse() does. Keys of up to 16 bytes are compared with two
overlapping loads.
Add value conversions: get<T>()/get_to() for arithmetic types,
bool, nullptr_t, strings (std::basic_string copied,
string_view_t without a copy), BasicJsonType, views, std::vector,
and maps with string keys; get_string() for the string without a
copy; number_token() for the number exactly as written in the
source; value() with keys and JSON pointers; and operator[]/at()/
contains() with JSON pointers. Everything else, including types
with from_json(), goes through materialize() of that subtree.
get<T>() of arithmetic types is inlined down to the conversion, so
reading an integer needs no call.
detail::json_pointer_access exposes a pointer's reference tokens
to code outside basic_json.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Make view lookups last-wins and chained access safe
* Lookups (operator[], at, find, contains, count, value, JSON pointers)
return the last member of a duplicate key, as materialize() and
parse() keep it.
* operator[] on a discarded view returns a discarded view instead of
throwing, so v["a"]["b"] is safe for a missing "a".
* operator[] and at() take any integer type (not only int and size_t),
fixing ambiguous calls with unsigned, long, std::int64_t, ...
* Fix the operator[] documentation, which claimed a discarded view for
a type mismatch where type_error.305 is thrown.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Replace the removed operator bool of basic_json_view in the header and its tests
A view is tested with is_discarded(); the lookups in at(), value() and
contains(json_pointer) and the unit tests no longer rely on the explicit
conversion to bool.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Use named documents in the json_view tests that called root() on a temporary
root() of an rvalue document is deleted, because the views would dangle.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Test discarded views with is_discarded() in the operator[] docs and examples
The explicit conversion to bool of basic_json_view is gone.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Return the first member of duplicate keys from lookups again
Looking up the last member of a duplicate key cannot stop at a match, so
every lookup scanned the whole object (1.6 to 3.4 times slower for small
objects). operator[](key), at, find, value, contains, count, and JSON
pointer resolution return the first member again, as yyjson and simdjson
do; materialize() and get<map>() keep the last value, as parse().
The documentation says so in the feature page and on each lookup page,
and explains how to get the value parse() would give. The integer index
templates and the discarded chaining of operator[] stay.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Do not force-inline the view's functions on MSVC
__forceinline makes MSVC report C4714 for function templates it cannot
inline (get<std::string>), an error under /WX. The forced inlining is
only a performance hint, so use plain inline there.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Make json_view.hpp pass include-what-you-use
Mark the includes that are needed by design (json.hpp, the macro
unscope, <tuple> for the tuple_size specialization), take size_t from
<cstring>, and drop the forward declaration of basic_json_document that
the friend declaration makes redundant.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Avoid GCC useless-cast warnings in the integer index tests
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Make json_view.hpp pass include-what-you-use
ci_single_binaries runs IWYU with --error on every header. For json_view.hpp
it suggested adding <array> (std::array is used), the headers that json.hpp
already provides (abi_config, abi_macros, input_adapters, json_pointer,
cpp_future, string_concat, value_t, json_fwd), and <version> for
std::nullptr_t, and removing <cstddef>.
- include <array>
- keep <cstddef> (nullptr_t, size_t; IWYU attributes them to <version> and <cstring>)
- tell IWYU not to suggest the headers that json.hpp provides: the amalgamated
json_view.hpp only includes json.hpp, so including them here would duplicate
their definitions
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Fix the clang-tidy 22 findings in json_view and its tests
The same changes as on the dump branch, where they were first made, so
that this branch passes clang-tidy on its own.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Regenerate the amalgamated headers
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Report one-character non-numeric array indices like basic_json in the view
Develop's #5800 made basic_json report a JSON pointer array index such as
"/a" as parse_error.109 instead of out_of_range.404, as longer ones were;
the view's array_index() follows, with "-" and the empty token still
unresolved.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Address the review of json_view element access
From gregmarr's review of #5622:
- count() counts every member with the key, so count(key) > 1 detects
duplicate keys; it was contains() as 0/1 before.
- get_to() passes types that get<T>() does not convert directly to
from_json with the existing value, as basic_json::get_to() does, so that
a from_json which sets only the fields present keeps the others.
- array_index() checks the empty token and "-" first; the results are
unchanged.
- Docs: no "if an exception is thrown" where a view never changes
anything; the borrowed source must also stay unmodified; items() on a
temporary view is safe; back()/front() notes shortened; the basic_json
see-also entries say how the view's results can differ.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Regenerate the amalgamated headers
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Count matching keys as unsigned in the json_view access test
The conditional added 1 or 0 as int to a std::size_t, which GCC rejects
with -Werror=sign-conversion (ci_test_standards_gcc).
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Address the second review round of json_view element access
From gregmarr's review of #5622:
- begin()/end(): "a null value or a discarded view iterates as an empty
range", singular like the primitive case before it.
- The class page's list of function groups has no trailing commas.
- document_data::key_equals() compares a key node with a string, for the
key comparisons that were spelled out in each lookup.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Regenerate the amalgamated headers
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Write the negated enable_if conditions of json_view with negation<>
With a ! or && in the condition, astyle spaces the whole template
header (template < ... >); detail::negation and a named trait keep it
compact, as the library writes such conditions elsewhere. From gregmarr's
review of #5630.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Regenerate the amalgamated headers
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Keep detail::negation out of json_view.hpp's enable_ifs
include-what-you-use asks json_view.hpp to include
detail/meta/type_traits.hpp for it, which the single header must not do
(the amalgamation would duplicate json's internals). The two conditions of
value() go through a trait in value.hpp, like the others.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Regenerate the amalgamated headers
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
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Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Niels Lohmann
43e97b629b