Mention NDJSON support on src/core/jsonl

src/core/jsonl/include/sourcemeta/core/jsonl.h

@@ -18,11 +18,21 @@
 /// @defgroup jsonl JSONL
 /// @brief A JSON Lines (https://jsonlines.org) implementation with iterator
 /// support. Every non-empty line in a JSONL stream is a complete, valid JSON
-/// value, and lines are separated by newline characters (U+000A). Multi-line
-/// JSON values are not supported, as per the JSONL specification. Blank and
-/// whitespace-only lines are skipped rather than treated as errors. JSON Lines
-/// is a convention rather than a formal specification, so tolerating stray
-/// blank lines is friendlier to real-world input.
+/// value of any type, and lines are separated by newline characters (U+000A),
+/// optionally preceded by a carriage return (U+000D). Multi-line JSON values
+/// are not supported, as per the JSONL specification.
+///
+/// JSON Lines and NDJSON (https://github.com/ndjson/ndjson-spec) describe the
+/// same format with minor differences, and this implementation accepts a
+/// superset of both:
+///
+/// - Blank and whitespace-only lines are skipped rather than treated as
+///   errors. JSON Lines considers them invalid, while NDJSON 3.2 permits
+///   ignoring them as long as the behavior is documented
+/// - A newline after the last value is optional. JSON Lines makes it a
+///   recommendation, while NDJSON 3.1 requires it when serializing
+/// - Whitespace is tolerated anywhere around a value, including carriage
+///   returns that NDJSON 3.1 only allows right before a newline
 ///
 /// This functionality is included as follows:
 ///

src/core/jsonl/include/sourcemeta/core/jsonl_iterator.h

@@ -17,9 +17,7 @@ namespace sourcemeta::core {
 
 /// @ingroup jsonl
 /// A forward iterator to parse JSON documents out of a JSON Lines stream. Blank
-/// and whitespace-only lines are skipped rather than treated as errors, as JSON
-/// Lines is a convention rather than a formal specification and tolerating
-/// stray blank lines is friendlier to real-world input.
+/// and whitespace-only lines are skipped rather than treated as errors.
 class SOURCEMETA_CORE_JSONL_EXPORT ConstJSONLIterator {
 public:
   /// Construct an iterator over the JSON documents in a stream.

src/core/jsonl/iterator.cc

@@ -34,7 +34,7 @@ auto ConstJSONLIterator::parse_next() -> JSON {
       row.pop_back();
     }
 
-    // Skip whitespace-only lines
+    // NDJSON 3.2 states that "The parser MAY silently ignore empty lines"
     bool has_content{false};
     for (const auto character : row) {
       if (character != internal::TOKEN_JSONL_WHITESPACE_SPACE<JSON::Char> &&