* Add FracturedJson formatting support for DOM serialization
Implements FracturedJson formatting as requested in issue #2576.
FracturedJson produces human-readable yet compact JSON output by
intelligently choosing between different layout strategies based on
content complexity, length, and structure similarity.
Key features:
- Four layout modes: inline, compact multiline, table, and expanded
- Structure analysis pass to compute metrics before formatting
- Table formatting for arrays of similar objects with column alignment
- Configurable options for line length, indentation, padding, etc.
New files:
- fractured_json.h: Public API with fractured_json_options struct
- fractured_json-inl.h: Implementation (~1000 lines)
- json_structure_analyzer.h: Structure analysis for layout decisions
- fractured_formatter.h: Formatter class using CRTP pattern
Usage:
dom::parser parser;
element doc = parser.parse(json_string);
std::cout << fractured_json(doc) << std::endl;
// Or with custom options:
fractured_json_options opts;
opts.indent_spaces = 2;
std::cout << fractured_json(doc, opts) << std::endl;
// Or format any JSON string (useful with reflection API):
auto formatted = fractured_json_string(minified_json);
Resolves#2576
* Add comprehensive tests for FracturedJson formatter
Adds 27 test cases covering all aspects of the FracturedJson formatter:
Core functionality tests (13):
- Roundtrip parsing verification
- Inline formatting for simple arrays and objects
- Expanded formatting for complex nested structures
- Compact multiline arrays with configurable items per line
- Table formatting for uniform arrays of objects
- Empty container handling
- All scalar types (string, int, uint, double, bool, null)
- String escaping (quotes, backslashes, control characters)
- Custom indentation options
- Deep nesting (10+ levels)
- Mixed type arrays
Edge case tests (11):
- Unicode strings (Chinese, emoji, Arabic, Russian, accented chars)
- Boundary numbers (INT64_MIN/MAX, UINT64_MAX, DBL_MIN/MAX)
- Nested arrays (arrays of arrays)
- Empty string values
- Keys with special characters (spaces, quotes, colons, etc.)
- Non-uniform arrays (should not trigger table mode)
- Very long strings (500+ chars)
- Large arrays (100 elements)
- Reflection API workflow simulation
- Control characters (tab, newline, CR, null)
- Single element containers
Option tests (3):
- Disable compact multiline mode
- Disable table format mode
- Disable all padding options
* Add FracturedJson integration with builder/reflection API
Extends FracturedJson to work seamlessly with the builder API, enabling
formatted output directly from C++ structs using static reflection.
New functions:
- to_fractured_json_string(obj, opts) - serialize struct to formatted JSON
- to_fractured_json(obj, output, opts) - same with output parameter
- extract_fractured_json<fields...>(obj, opts) - format only specific fields
These functions combine the builder's reflection-based serialization with
FracturedJson formatting in a single convenient call:
struct User { int id; std::string name; bool active; };
User user{1, "Alice", true};
// Minified output (existing):
auto minified = to_json_string(user);
// {"id":1,"name":"Alice","active":true}
// Formatted output (new):
auto formatted = to_fractured_json_string(user);
// { "id": 1, "name": "Alice", "active": true }
// Partial extraction with formatting:
auto partial = extract_fractured_json<"id", "name">(user);
// { "id": 1, "name": "Alice" }
New files:
- generic/builder/fractured_json_builder.h - builder integration
- tests/builder/static_reflection_fractured_json_tests.cpp - 7 tests
* Fix INT64_MIN overflow and implement table_similarity_threshold
- Fix undefined behavior when negating INT64_MIN in estimate_number_length()
and measure_value_length() by returning 20 (the exact length of the
string representation) directly
- Actually use table_similarity_threshold in check_array_uniformity() by
calling compute_object_similarity() to compare objects against the first
object in the array
* Fix -Werror=effc++ member initialization warnings
Initialize all member variables in member initialization lists to
satisfy GCC's -Werror=effc++ flag:
- element_metrics::common_keys - add {} default initializer
- structure_analyzer - add default constructor with member init list
- fractured_formatter - add column_widths_{} to constructor
- fractured_string_builder - add analyzer_{} to constructor
* Add Rule of Five to structure_analyzer class
The class has a pointer member (current_opts_) which triggers
-Werror=effc++ requiring explicit copy/move operations. Delete
copy operations (class shouldn't be copied due to cache) and
default move operations.
* Fix Windows build: wrap std::max to avoid macro conflict
Windows.h defines max/min macros that interfere with std::max/std::min.
Wrapping in parentheses as (std::max)(...) prevents macro expansion.
* Fix GCC 15 false positive -Wfree-nonheap-object warning
GCC 15 on MINGW64 gives a false positive warning in parser_moving_parser()
when the std::vector<std::string> goes out of scope. Suppress this
specific warning with a pragma for GCC builds.
* Fix metrics cache key bug by passing metrics through recursion
The cache was using element addresses as keys, but dom::element objects
are lightweight wrappers that get copied during iteration, causing
different addresses between analysis and formatting phases. This resulted
in cache misses and fallback to empty metrics.
Solution: Store child metrics in the element_metrics struct and pass
them through recursive calls, eliminating the need for address-based
caching entirely.
Changes:
- Add children vector to element_metrics for hierarchical metrics
- Remove metrics_cache_ and related get_metrics/has_metrics methods
- Update all format functions to accept and pass child metrics
- Add public analyze_array/analyze_object overloads for standalone use
* Add ignore patterns for Node.js, Rust, and generated files
Add entries for node_modules, package-lock.json, Rust target
directories, local ablation artifacts, and generated documentation
files.
* Refactor: extract analyze_scalar helper to reduce code duplication
Extract common scalar type handling (STRING, INT64, UINT64, DOUBLE,
BOOL, NULL_VALUE) into a dedicated analyze_scalar method. Each scalar
type shares the same initialization pattern for complexity, child_count,
can_inline, and recommended_layout.
Also simplify boolean formatting in format_scalar to use ternary operator.
* Fix formatting and duplicate error message in amalgamate.py
Reformat cramped is_amalgamator condition to multi-line for readability.
Fix duplicate error message text in _included_filename_root and use
correct variable name (relative_root instead of root).
* Refactor: add count_newlines helper in fractured_json tests
Extract repeated newline counting loop into a reusable static helper
function, used by inline_array_test, inline_object_test, and
expanded_test.
* Revert "Add ignore patterns for Node.js, Rust, and generated files"
This reverts commit 4760ea7cd0.
* various minor changes
---------
Co-authored-by: Daniel Lemire <daniel@lemire.me>
* Initial work on JSON builder
* moving the files back to ondemand for now.
* tweak
* more later
* update
* minor edits
* dropping vs arm (missing support)
* adding tests. we still specialized write_string_escaped
* tweaking
* fix typo
* tweaking the approach
* minor fix
* missing store
* another missing store
* Attempt at fixing failing serialization tests. (#2292)
* Fixing appeand_float typo (#2294)
* applying a couple of fixes
* updating single header
* fix for pre C++17 if constexpr
* Fixing unused argument problem and updating the singleheader file
* various pedantic fixes
* Sketch of builder
* reordering.
* simplify
* Adding draft of static reflection based deserialization
* Updating simdjson singleheader
* patching the automated deserialization.
* automated
* Adding support for smart pointers of user defined types.
* Adding specialization for smart pointers for basic types. I think it is highly likely that this can be done in a more generic way.
* Referncing a later version of rapidjson that fixed the issue related with assignment attempt of a const variable for GenericStringRef class.
* guarding the tests
* adding documentation for string_builder
* saving
* rename to 'append'
* saving
* non-functional benchmarks (#2342)
* non-functional benchmarks
* Fix typo
* various fixes
* tweaking
---------
Co-authored-by: Daniel Lemire <dlemire@lemire.me>
Co-authored-by: Francisco Geiman Thiesen <franciscogthiesen@gmail.com>
* tuning
* various minor fixes
* minor tweak
* minor simplification
* updating amal
* adding a cast
* update
* fancy casting
* removing dead code
* Pushing latest changes. CITM benchmark is still not working.
* Still not working, but now I am getting only 10 errors.
* add static reflection benchmark to 'large random' benchmark and allows (#2349)
deserialization (with static reflection) from objects and arrays.
Co-authored-by: Daniel Lemire <dlemire@lemire.me>
* Removing std::map from CitmCatalog definition, since that is not currently supported.
* Added free to rust bench, segfault is still happening..
* The syntax changed: ^E became ^^E. (#2350)
* The syntax changed: ^E became ^^E.
* guarding
---------
Co-authored-by: Daniel Lemire <dlemire@lemire.me>
* Adding support for string_view_keyed_map types.
* Adding concepts as a conditional include.
* updating single-header
* Adding concepts to ondemand deps
* rust benchmark is finally working
* Fixing small typo in docs.
* adding docker config and instructions so that our users can test the static reflection (#2358)
* adding docker config and instructions so that our users can test the
static reflection
* completing the instructions
* pruning white spaces
---------
Co-authored-by: Daniel Lemire <dlemire@lemire.me>
* minor optimizations on the JSON builder branch
* avoiding undef behaviour
* saving
* somewhat nicer builder
* make it possible to run just one benchmark
* adding linux perf
* fixing minor issue
* updating swar
* Adding real world compilation benchmark (#2379)
* Adding compilation benchmark for json parsing with and without reflection
* Moving it to the benchmark folder, also reducing a bit the number of iterations.
* Removing script from root folder.
* Reducing number of iterations
* Update benchmark/benchmark_reflection_usage_compilation.sh
Co-authored-by: Daniel Lemire <daniel@lemire.me>
* Update benchmark/benchmark_reflection_usage_compilation.sh
Co-authored-by: Daniel Lemire <daniel@lemire.me>
* Update benchmark/benchmark_reflection_usage_compilation.sh
Co-authored-by: Daniel Lemire <daniel@lemire.me>
* Making the script more customizable and also test whether the compiler being used supports reflection before actually running the benchmark
---------
Co-authored-by: Daniel Lemire <daniel@lemire.me>
* Using define_static_string from https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2025/p3491r2.html (#2389)
* Applying changes needed after latest reflection paper updates.
* Working, but no template for yet.
* Updating single-header to incldue the use of define_static_string.
* copying over master
---------
Co-authored-by: Daniel Lemire <dlemire@lemire.me>
Co-authored-by: Francisco Geiman Thiesen <franciscogthiesen@gmail.com>
* Let us time minify
* Making AVX-512 available by default.
* Silencing some maybe-uninitialized warning under GCC (warning appears in the standard library).
* Making the Python amalgamation script a bit more Windows friendly.
* We do not try to silence -Wmaybe-uninitialized under clang.
This eliminates the possibility of inlining target failures for ondemand
Also makes it so we always compile common architectures needed by simdjson.cpp in simdjson.h, since amalgamation has no way to reason about whether to include / exclude it.
Daniel Lemire