YAML support

CHANGELOG.md

@@ -14,6 +14,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 - `LottieReader::parseFile()`, `parseData()`, `parseStream()`, and `parseFromZip()` now return `ResultValue<AnimationComposition::Ptr>` and no longer take a trailing `String* outError` out-parameter; check `wasOk()`/`failed()` and read the message via `getErrorMessage()`.
 - `AnimationFrameExporter` is now an instance-based class bound to a `GraphicsContext` (construct `AnimationFrameExporter exporter (ctx);` then call `exporter.renderFrame(anim, …)` / `exporter.renderAllFrames(…)` / `exporter.exportToGif(anim, …)`), so it can own and reuse the GPU matte-composite pipeline across frames instead of recompiling it per frame. The `exportToGif(frames, frameRate, …)` frame-sequence encoder remains a static helper.
 
+### Core
+
+- Added a `YAML` class: a self-contained YAML parser and writer converting between YAML text and `var` (`parse`, `fromString`, `toString`, `writeToStream`, `FormatOptions`), with core-schema type resolution, block/flow collections, block scalars, and anchors/aliases/merge keys
+
 ### Graphics
 
 - Added a native WebGPU `GraphicsContext` backend for Emscripten via the Emdawnwebgpu port (`RIVE_WEBGPU=2` + `--use-port=emdawnwebgpu`, enabled with the `ENABLE_EMSCRIPTEN_WEBGPU` parameter of `yup_standalone_app`), rendering Rive content through the browser's WebGPU API without Dawn

docs/core/data-interchange.md

@@ -83,6 +83,63 @@ Related helpers:
 `JSON::parse` accepts only a valid JSON object or array at the top level.
 ```
 
+## YAML
+
+The `YAML` class converts between YAML text and `var`, mirroring the `JSON`
+interface: `parse` (with `Result` error detail), `fromString`, `toString` and
+`writeToStream`, plus `FormatOptions` to choose spacing style and number
+precision.
+
+```cpp
+var parsed = YAML::parse (yamlText);        // var() on failure
+Result r = YAML::parse (yamlText, result);  // error detail with line numbers
+String text = YAML::toString (parsed);      // block style by default
+String flow = YAML::toString (parsed, YAML::FormatOptions {}.withSpacing (YAML::Spacing::singleLine));
+String none = YAML::toString (parsed, YAML::FormatOptions {}.withSpacing (YAML::Spacing::none));
+```
+
+### Supported features
+
+**Type resolution** according to the YAML core schema:
+
+- `null`, `~` → void
+- `true`/`false`, `yes`/`no`, `on`/`off`, `y`/`n` (case-insensitive) → bool
+- Integers: decimal, hex (`0x1F`), octal (`0o17`), with `_` separators (`1_000`)
+- Floats: `3.14`, `1e5`, `1.5e-3`, `.5`, `1.`; `.inf`/`-.inf`, `.nan`
+- Strings: plain, single-quoted, double-quoted scalars
+
+**Collections:** block (`key: value`, `- item`) and flow (`{a: 1}`, `[1, 2]`)
+with arbitrary nesting.
+
+**Block scalars:** literal (`|`) and folded (`>`) with chomping indicators
+(`-`/`+`) and explicit indentation (`|2`).
+
+**Anchors, aliases, and merge keys:** `&anchor` defines an anchor on any node,
+`*anchor` dereferences it (deep-copied into the result), and `<<: *anchor`
+merges mapped values in a YAML 1.1-compatible way.
+
+**Quoted string utilities:** `escapeString` escapes a string for double-quoted
+YAML output; `parseQuotedString` parses a quoted YAML scalar from a raw
+character pointer.
+
+### Error handling and safety
+
+`YAML::parse(text, result)` returns a `Result` with line-numbered error messages
+for malformed input. The parser enforces:
+
+- Maximum nesting depth of 512 to prevent stack overflow
+- Cyclic alias detection (`&a [*a]` is rejected)
+- Duplicate anchor detection (`&a 1\n&a 2` is rejected)
+
+```{note}
+`YAML::parse` accepts only a valid YAML mapping or sequence at the top level.
+Use `YAML::fromString` to parse plain scalars, booleans, or numbers. Custom
+tags, multi-document streams (`---`/`...`), and the merge key `<<` in a quoted
+context are not supported. The writer never emits anchors, aliases or merge
+keys; YAML 1.1 boolean spellings (`yes`/`no`/`on`/`off`/`y`/`n`) are
+recognised on input but emitted as quoted strings to ensure unambiguous
+interop.
+
 ## XML
 
 `yup_core` ships a small, self-contained XML DOM: `XmlElement` (a mutable node)

modules/yup_core/javascript/yup_JSON.cpp

@@ -317,8 +317,12 @@ struct JSONParser
                 throwError ("Expected a property name in double-quotes", errorLocation);
 
             errorLocation = currentLocation;
-            Identifier propertyName (parseString ('"'));
 
+            auto propertyString = parseString ('"');
+            if (propertyString.isEmpty())
+                throwError ("Property name cannot be empty", errorLocation);
+
+            auto propertyName = Identifier (propertyString);
             if (! propertyName.isValid())
                 throwError ("Invalid property name", errorLocation);
 
@@ -418,7 +422,7 @@ struct JSONFormatter
                     break;
 
                 default:
-                    if (c >= 32 && c < 127)
+                    if (CharacterFunctions::isAsciiPrintable (c))
                     {
                         out << (char) c;
                     }

modules/yup_core/text/yup_CharacterFunctions.cpp

@@ -433,6 +433,16 @@ bool CharacterFunctions::isPrintable (const yup_wchar character) noexcept
     return iswprint ((wint_t) character) != 0;
 }
 
+bool CharacterFunctions::isAsciiPrintable (const yup_wchar character) noexcept
+{
+    return character >= 32 && character < 127;
+}
+
+bool CharacterFunctions::isControlCharacter (const yup_wchar character) noexcept
+{
+    return character < 0x20 || character == 0x7f;
+}
+
 int CharacterFunctions::getHexDigitValue (const yup_wchar digit) noexcept
 {
     auto d = (unsigned int) (digit - '0');

modules/yup_core/text/yup_CharacterFunctions.h

@@ -183,6 +183,12 @@ class YUP_API CharacterFunctions
     */
     static bool isPrintable (yup_wchar character) noexcept;
 
+    /** Checks whether a character is a printable ASCII character (codes 32–126 inclusive). */
+    static bool isAsciiPrintable (yup_wchar character) noexcept;
+
+    /** Checks whether a character is an ASCII control character (codes 0–31 or 127). */
+    static bool isControlCharacter (yup_wchar character) noexcept;
+
     /** Returns 0 to 16 for '0' to 'F", or -1 for characters that aren't a legal hex digit. */
     static int getHexDigitValue (yup_wchar digit) noexcept;