1 files changed, 117 insertions, 0 deletions
diff --git a/intl/icu_capi/cpp/docs/source/fallbacker_ffi.rst b/intl/icu_capi/cpp/docs/source/fallbacker_ffi.rst
new file mode 100644
index 0000000000..a4b17b785c
--- /dev/null
+++ b/intl/icu_capi/cpp/docs/source/fallbacker_ffi.rst
@@ -0,0 +1,117 @@
+``fallbacker::ffi``
+===================
+
+.. cpp:struct:: ICU4XLocaleFallbackConfig
+
+    Collection of configurations for the ICU4X fallback algorithm.
+
+    See the `Rust documentation for LocaleFallbackConfig <https://docs.rs/icu/latest/icu/locid_transform/fallback/struct.LocaleFallbackConfig.html>`__ for more information.
+
+
+    .. cpp:member:: ICU4XLocaleFallbackPriority priority
+
+        Choice of priority mode.
+
+
+    .. cpp:member:: std::string_view extension_key
+
+        An empty string is considered ``None``.
+
+
+    .. cpp:member:: ICU4XLocaleFallbackSupplement fallback_supplement
+
+        Fallback supplement data key to customize fallback rules.
+
+
+.. cpp:class:: ICU4XLocaleFallbackIterator
+
+    An iterator over the locale under fallback.
+
+    See the `Rust documentation for LocaleFallbackIterator <https://docs.rs/icu/latest/icu/locid_transform/fallback/struct.LocaleFallbackIterator.html>`__ for more information.
+
+
+    .. cpp:function:: ICU4XLocale get() const
+
+        Gets a snapshot of the current state of the locale.
+
+        See the `Rust documentation for get <https://docs.rs/icu/latest/icu/locid_transform/fallback/struct.LocaleFallbackIterator.html#method.get>`__ for more information.
+
+
+    .. cpp:function:: void step()
+
+        Performs one step of the fallback algorithm, mutating the locale.
+
+        See the `Rust documentation for step <https://docs.rs/icu/latest/icu/locid_transform/fallback/struct.LocaleFallbackIterator.html#method.step>`__ for more information.
+
+
+.. cpp:enum-struct:: ICU4XLocaleFallbackPriority
+
+    Priority mode for the ICU4X fallback algorithm.
+
+    See the `Rust documentation for LocaleFallbackPriority <https://docs.rs/icu/latest/icu/locid_transform/fallback/enum.LocaleFallbackPriority.html>`__ for more information.
+
+
+    .. cpp:enumerator:: Language
+
+    .. cpp:enumerator:: Region
+
+    .. cpp:enumerator:: Collation
+
+.. cpp:enum-struct:: ICU4XLocaleFallbackSupplement
+
+    What additional data is required to load when performing fallback.
+
+    See the `Rust documentation for LocaleFallbackSupplement <https://docs.rs/icu/latest/icu/locid_transform/fallback/enum.LocaleFallbackSupplement.html>`__ for more information.
+
+
+    .. cpp:enumerator:: None
+
+    .. cpp:enumerator:: Collation
+
+.. cpp:class:: ICU4XLocaleFallbacker
+
+    An object that runs the ICU4X locale fallback algorithm.
+
+    See the `Rust documentation for LocaleFallbacker <https://docs.rs/icu/latest/icu/locid_transform/fallback/struct.LocaleFallbacker.html>`__ for more information.
+
+
+    .. cpp:function:: static diplomat::result<ICU4XLocaleFallbacker, ICU4XError> create(const ICU4XDataProvider& provider)
+
+        Creates a new ``ICU4XLocaleFallbacker`` from a data provider.
+
+        See the `Rust documentation for new <https://docs.rs/icu/latest/icu/locid_transform/fallback/struct.LocaleFallbacker.html#method.new>`__ for more information.
+
+
+    .. cpp:function:: static ICU4XLocaleFallbacker create_without_data()
+
+        Creates a new ``ICU4XLocaleFallbacker`` without data for limited functionality.
+
+        See the `Rust documentation for new_without_data <https://docs.rs/icu/latest/icu/locid_transform/fallback/struct.LocaleFallbacker.html#method.new_without_data>`__ for more information.
+
+
+    .. cpp:function:: diplomat::result<ICU4XLocaleFallbackerWithConfig, ICU4XError> for_config(ICU4XLocaleFallbackConfig config) const
+
+        Associates this ``ICU4XLocaleFallbacker`` with configuration options.
+
+        See the `Rust documentation for for_config <https://docs.rs/icu/latest/icu/locid_transform/fallback/struct.LocaleFallbacker.html#method.for_config>`__ for more information.
+
+        Lifetimes: ``this`` must live at least as long as the output.
+
+
+.. cpp:class:: ICU4XLocaleFallbackerWithConfig
+
+    An object that runs the ICU4X locale fallback algorithm with specific configurations.
+
+    See the `Rust documentation for LocaleFallbacker <https://docs.rs/icu/latest/icu/locid_transform/fallback/struct.LocaleFallbacker.html>`__ for more information.
+
+    See the `Rust documentation for LocaleFallbackerWithConfig <https://docs.rs/icu/latest/icu/locid_transform/fallback/struct.LocaleFallbackerWithConfig.html>`__ for more information.
+
+
+    .. cpp:function:: ICU4XLocaleFallbackIterator fallback_for_locale(const ICU4XLocale& locale) const
+
+        Creates an iterator from a locale with each step of fallback.
+
+        See the `Rust documentation for fallback_for <https://docs.rs/icu/latest/icu/locid_transform/fallback/struct.LocaleFallbacker.html#method.fallback_for>`__ for more information.
+
+        Lifetimes: ``this`` must live at least as long as the output.
+