feat: add WasmTupleChain

Signed-off-by: Henry <mail@henrygressmann.de>

3 files changed, 215 insertions, 53 deletions

diff --git a/crates/tinywasm/src/func.rs b/crates/tinywasm/src/func.rs
index 3c94de2..fa8e755 100644
--- a/crates/tinywasm/src/func.rs
+++ b/crates/tinywasm/src/func.rs
@@ -152,13 +152,13 @@ impl HostFunction {
     /// Create a new typed host function import.
     pub fn from<P, R>(store: &mut Store, func: impl Fn(FuncContext<'_>, P) -> Result<R> + 'static) -> Function
     where
-        P: FromWasmValueTuple + WasmTypesFromTuple,
-        R: IntoWasmValueTuple + WasmTypesFromTuple,
+        P: FromWasmValues + ToWasmTypes,
+        R: IntoWasmValues + ToWasmTypes,
     {
         let inner_func = move |ctx: FuncContext<'_>, args: &[WasmValue]| -> Result<Vec<WasmValue>> {
-            let args = P::from_wasm_value_tuple(args)?;
+            let args = P::from_wasm_values(args)?;
             let result = func(ctx, args)?;
-            Ok(result.into_wasm_value_tuple())
+            Ok(result.into_wasm_values())
         };
 
         let ty = Arc::new(tinywasm_types::FuncType::new(&P::wasm_types(), &R::wasm_types()));
@@ -383,47 +383,45 @@ fn collect_call_results(value_stack: &mut ValueStack, func_ty: &FuncType) -> Res
     Ok(res)
 }
 
-pub trait IntoWasmValueTuple {
-    fn into_wasm_value_tuple(self) -> Vec<WasmValue>;
+pub trait IntoWasmValues {
+    fn into_wasm_values(self) -> Vec<WasmValue>;
 }
 
-pub trait FromWasmValueTuple {
-    fn from_wasm_value_tuple(values: &[WasmValue]) -> Result<Self>
-    where
-        Self: Sized;
+pub trait FromWasmValues: Sized {
+    fn from_wasm_values(values: &[WasmValue]) -> Result<Self>;
 }
 
-impl<P: IntoWasmValueTuple, R: FromWasmValueTuple> FunctionTyped<P, R> {
+impl<P: IntoWasmValues, R: FromWasmValues> FunctionTyped<P, R> {
     /// Call a typed function
     pub fn call(&self, store: &mut Store, params: P) -> Result<R> {
         // Convert params into Vec<WasmValue>
-        let wasm_values = params.into_wasm_value_tuple();
+        let wasm_values = params.into_wasm_values();
 
         // Call the underlying WASM function
         let result = self.func.call(store, &wasm_values)?;
 
         // Convert the Vec<WasmValue> back to R
-        R::from_wasm_value_tuple(&result)
+        R::from_wasm_values(&result)
     }
 
     /// Call a typed function and return a resumable execution handle.
     ///
     /// The handle keeps a mutable borrow of the [`Store`] until completion.
     pub fn call_resumable<'store>(&self, store: &'store mut Store, params: P) -> Result<FuncExecutionTyped<'store, R>> {
-        let wasm_values = params.into_wasm_value_tuple();
+        let wasm_values = params.into_wasm_values();
         let execution = self.func.call_resumable(store, &wasm_values)?;
         Ok(FuncExecutionTyped { execution, marker: core::marker::PhantomData })
     }
 }
 
-impl<'store, R: FromWasmValueTuple> FuncExecutionTyped<'store, R> {
+impl<'store, R: FromWasmValues> FuncExecutionTyped<'store, R> {
     /// Resume typed execution with up to `fuel` units of fuel.
     ///
     /// Fuel is accounted in chunks, so execution may overshoot the requested
     /// fuel before returning [`ExecProgress::Suspended`].
     pub fn resume_with_fuel(&mut self, fuel: u32) -> Result<ExecProgress<R>> {
         match self.execution.resume_with_fuel(fuel)? {
-            ExecProgress::Completed(values) => Ok(ExecProgress::Completed(R::from_wasm_value_tuple(&values)?)),
+            ExecProgress::Completed(values) => Ok(ExecProgress::Completed(R::from_wasm_values(&values)?)),
             ExecProgress::Suspended => Ok(ExecProgress::Suspended),
         }
     }
@@ -435,18 +433,22 @@ impl<'store, R: FromWasmValueTuple> FuncExecutionTyped<'store, R> {
     /// time budget before returning [`ExecProgress::Suspended`].
     pub fn resume_with_time_budget(&mut self, time_budget: crate::std::time::Duration) -> Result<ExecProgress<R>> {
         match self.execution.resume_with_time_budget(time_budget)? {
-            ExecProgress::Completed(values) => Ok(ExecProgress::Completed(R::from_wasm_value_tuple(&values)?)),
+            ExecProgress::Completed(values) => Ok(ExecProgress::Completed(R::from_wasm_values(&values)?)),
             ExecProgress::Suspended => Ok(ExecProgress::Suspended),
         }
     }
 }
 
-pub trait WasmTypesFromTuple {
+/// Describes the WebAssembly value types produced by a Rust value or tuple shape.
+pub trait ToWasmTypes {
+    /// Return the flattened WebAssembly value types for this tuple shape.
     fn wasm_types() -> Box<[WasmType]>;
 }
 
+/// Describes the WebAssembly value types produced by a scalar Rust type.
 pub trait ToWasmType {
-    fn to_wasm_type() -> WasmType;
+    /// Return the single WebAssembly value type for this scalar type.
+    fn wasm_type() -> WasmType;
 }
 
 macro_rules! impl_scalar_wasm_traits {
@@ -454,34 +456,34 @@ macro_rules! impl_scalar_wasm_traits {
         $(
             impl ToWasmType for $T {
                 #[inline]
-                fn to_wasm_type() -> WasmType {
+                fn wasm_type() -> WasmType {
                     WasmType::$val_ty
                 }
             }
 
-            impl WasmTypesFromTuple for $T {
+            impl ToWasmTypes for $T {
                 #[inline]
                 fn wasm_types() -> Box<[WasmType]> {
                     Box::new([WasmType::$val_ty])
                 }
             }
 
-            impl IntoWasmValueTuple for $T {
+            impl IntoWasmValues for $T {
                 #[inline]
-                fn into_wasm_value_tuple(self) -> Vec<WasmValue> {
+                fn into_wasm_values(self) -> Vec<WasmValue> {
                     vec![self.into()]
                 }
             }
 
-            impl FromWasmValueTuple for $T {
+            impl FromWasmValues for $T {
                 #[inline]
-                fn from_wasm_value_tuple(values: &[WasmValue]) -> Result<Self> {
+                fn from_wasm_values(values: &[WasmValue]) -> Result<Self> {
                     let value = *values
                         .first()
                         .ok_or(Error::Other("Not enough values in WasmValue vector".to_string()))?;
                     <$T>::try_from(value).map_err(|e| {
                         Error::Other(format!(
-                            "FromWasmValueTuple: Could not convert WasmValue to expected type: {:?}",
+                            "FromWasmValues: Could not convert WasmValue to expected type: {:?}",
                             e
                         ))
                     })
@@ -493,34 +495,34 @@ macro_rules! impl_scalar_wasm_traits {
 
 macro_rules! impl_tuple_traits {
     ($($T:ident),+) => {
-        impl<$($T),+> WasmTypesFromTuple for ($($T,)+)
+        impl<$($T),+> ToWasmTypes for ($($T,)+)
         where
             $($T: ToWasmType,)+
         {
             #[inline]
             fn wasm_types() -> Box<[WasmType]> {
-                Box::new([$($T::to_wasm_type(),)+])
+                Box::new([$($T::wasm_type(),)+])
             }
         }
 
-        impl<$($T),+> IntoWasmValueTuple for ($($T,)+)
+        impl<$($T),+> IntoWasmValues for ($($T,)+)
         where
             $($T: Into<WasmValue>,)+
         {
             #[allow(non_snake_case)]
             #[inline]
-            fn into_wasm_value_tuple(self) -> Vec<WasmValue> {
+            fn into_wasm_values(self) -> Vec<WasmValue> {
                 let ($($T,)+) = self;
                 vec![$($T.into(),)+]
             }
         }
 
-        impl<$($T),+> FromWasmValueTuple for ($($T,)+)
+        impl<$($T),+> FromWasmValues for ($($T,)+)
         where
             $($T: TryFrom<WasmValue, Error = ()>,)+
         {
             #[inline]
-            fn from_wasm_value_tuple(values: &[WasmValue]) -> Result<Self> {
+            fn from_wasm_values(values: &[WasmValue]) -> Result<Self> {
                 let mut iter = values.iter();
 
                 Ok((
@@ -530,7 +532,7 @@ macro_rules! impl_tuple_traits {
                             .ok_or(Error::Other("Not enough values in WasmValue vector".to_string()))?
                         )
                         .map_err(|e| Error::Other(format!(
-                            "FromWasmValueTuple: Could not convert WasmValue to expected type: {:?}",
+                            "FromWasmValues: Could not convert WasmValue to expected type: {:?}",
                             e,
                         )))?,
                     )+
@@ -554,10 +556,6 @@ macro_rules! impl_tuple {
         $macro!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10);
         $macro!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11);
         $macro!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12);
-        $macro!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13);
-        $macro!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14);
-        $macro!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15);
-        $macro!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16);
     };
 }
 
@@ -571,23 +569,125 @@ impl_scalar_wasm_traits!(
 );
 impl_tuple!(impl_tuple_traits);
 
-impl WasmTypesFromTuple for () {
+/// A helper type for using tuples of arbitrary number of elements as function parameters or results,
+/// by concatenating the Wasm types of each element.
+///
+/// This is useful when a function signature exceeds tuple arity 12. `tinywasm` only implements
+/// direct tuple conversions up to arity 12, but `WasmTupleChain` lets you describe longer
+/// signatures by combining smaller tuples at the type level.
+///
+/// ## Example
+/// ```rust
+/// # fn main() -> tinywasm::Result<()> {
+/// # use tinywasm::{ModuleInstance, Store, WasmTupleChain};
+/// # let wasm = wat::parse_str(r#"
+/// #     (module
+/// #       (func (export "echo13")
+/// #         (param i32 i32 i32 i32 i32 i32 i32 i32 i32 i32 i32 i32 i32)
+/// #         (result i32 i32 i32 i32 i32 i32 i32 i32 i32 i32 i32 i32 i32)
+/// #         local.get 0
+/// #         local.get 1
+/// #         local.get 2
+/// #         local.get 3
+/// #         local.get 4
+/// #         local.get 5
+/// #         local.get 6
+/// #         local.get 7
+/// #         local.get 8
+/// #         local.get 9
+/// #         local.get 10
+/// #         local.get 11
+/// #         local.get 12)
+/// #     )
+/// # "#).expect("valid wat");
+/// # let module = tinywasm::parse_bytes(&wasm)?;
+/// # let mut store = Store::default();
+/// # let instance = ModuleInstance::instantiate(&mut store, &module, None)?;
+///
+/// type Params = WasmTupleChain<
+///     (i32, i32, i32, i32, i32, i32),
+///     (i32, i32, i32, i32, i32, i32, i32),
+/// >;
+/// type Results = WasmTupleChain<
+///     (i32, i32, i32, i32, i32, i32),
+///     (i32, i32, i32, i32, i32, i32, i32),
+/// >;
+///
+/// let echo13 = instance.func::<Params, Results>(&store, "echo13")?;
+/// let result = echo13.call(&mut store, ((1, 2, 3, 4, 5, 6), (7, 8, 9, 10, 11, 12, 13)).into())?;
+/// assert_eq!(result.into_inner(), ((1, 2, 3, 4, 5, 6), (7, 8, 9, 10, 11, 12, 13)));
+/// # Ok(())
+/// # }
+/// ```
+#[derive(Default)]
+pub struct WasmTupleChain<T1, T2>(T1, T2);
+
+impl<T1, T2> WasmTupleChain<T1, T2> {
+    /// Create a new concatenated tuple wrapper.
+    pub const fn new(left: T1, right: T2) -> Self {
+        Self(left, right)
+    }
+
+    /// Split the wrapper back into its two component values.
+    pub fn into_inner(self) -> (T1, T2) {
+        (self.0, self.1)
+    }
+}
+
+impl<T1, T2> From<(T1, T2)> for WasmTupleChain<T1, T2> {
+    fn from((left, right): (T1, T2)) -> Self {
+        Self::new(left, right)
+    }
+}
+
+impl<T1: ToWasmTypes, T2: ToWasmTypes> ToWasmTypes for WasmTupleChain<T1, T2> {
+    #[inline]
+    fn wasm_types() -> Box<[WasmType]> {
+        let mut types = Vec::new();
+        types.extend_from_slice(&T1::wasm_types());
+        types.extend_from_slice(&T2::wasm_types());
+        types.into_boxed_slice()
+    }
+}
+
+impl<T1: IntoWasmValues, T2: IntoWasmValues> IntoWasmValues for WasmTupleChain<T1, T2> {
+    #[inline]
+    fn into_wasm_values(self) -> Vec<WasmValue> {
+        let (left, right) = self.into_inner();
+        let mut values = Vec::new();
+        values.extend(left.into_wasm_values());
+        values.extend(right.into_wasm_values());
+        values
+    }
+}
+
+impl<T1: FromWasmValues + ToWasmTypes, T2: FromWasmValues> FromWasmValues for WasmTupleChain<T1, T2> {
+    #[inline]
+    fn from_wasm_values(values: &[WasmValue]) -> Result<Self> {
+        let left_len = T1::wasm_types().len();
+        let left = T1::from_wasm_values(&values[..values.len().min(left_len)])?;
+        let right = T2::from_wasm_values(values.get(left_len..).unwrap_or(&[]))?;
+        Ok(Self::new(left, right))
+    }
+}
+
+impl ToWasmTypes for () {
     #[inline]
     fn wasm_types() -> Box<[WasmType]> {
         Box::new([])
     }
 }
 
-impl IntoWasmValueTuple for () {
+impl IntoWasmValues for () {
     #[inline]
-    fn into_wasm_value_tuple(self) -> Vec<WasmValue> {
+    fn into_wasm_values(self) -> Vec<WasmValue> {
         vec![]
     }
 }
 
-impl FromWasmValueTuple for () {
+impl FromWasmValues for () {
     #[inline]
-    fn from_wasm_value_tuple(_values: &[WasmValue]) -> Result<Self> {
+    fn from_wasm_values(_values: &[WasmValue]) -> Result<Self> {
         Ok(())
     }
 }
diff --git a/crates/tinywasm/src/instance.rs b/crates/tinywasm/src/instance.rs
index e5a2d88..b050f0b 100644
--- a/crates/tinywasm/src/instance.rs
+++ b/crates/tinywasm/src/instance.rs
@@ -5,7 +5,7 @@ use alloc::sync::Arc;
 use alloc::{format, rc::Rc};
 use tinywasm_types::*;
 
-use crate::func::{FromWasmValueTuple, IntoWasmValueTuple, WasmTypesFromTuple};
+use crate::func::{FromWasmValues, IntoWasmValues, ToWasmTypes};
 use crate::{Error, Function, FunctionTyped, Global, Imports, Memory, Result, Store, Table, Trap};
 
 /// A typed view over an exported extern value.
@@ -22,6 +22,22 @@ pub enum ExternItem {
 
 /// An instantiated WebAssembly module
 ///
+/// Create a `ModuleInstance` by parsing a module, creating a [`Store`], and then calling
+/// [`ModuleInstance::instantiate`].
+///
+/// ## Example
+/// ```rust
+/// # fn main() -> tinywasm::Result<()> {
+/// # use tinywasm::{ModuleInstance, Store};
+/// # let wasm = wat::parse_str("(module)").expect("valid wat");
+/// let module = tinywasm::parse_bytes(&wasm)?;
+/// let mut store = Store::default();
+/// let instance = ModuleInstance::instantiate(&mut store, &module, None)?;
+/// # let _ = instance;
+/// # Ok(())
+/// # }
+/// ```
+///
 /// Backed by an Rc, so cloning is cheap
 ///
 /// See <https://webassembly.github.io/spec/core/exec/runtime.html#module-instances>
@@ -305,6 +321,30 @@ impl ModuleInstance {
     }
 
     /// Get a function export by name.
+    ///
+    /// ## Example
+    /// ```rust
+    /// # fn main() -> tinywasm::Result<()> {
+    /// # use tinywasm::{ModuleInstance, Store};
+    /// # use tinywasm::types::WasmValue;
+    /// # let wasm = wat::parse_str(r#"
+    /// #     (module
+    /// #       (func (export "add") (param i32 i32) (result i32)
+    /// #         local.get 0
+    /// #         local.get 1
+    /// #         i32.add))
+    /// # "#).expect("valid wat");
+    /// # let module = tinywasm::parse_bytes(&wasm)?;
+    /// # let mut store = Store::default();
+    /// let instance = ModuleInstance::instantiate(&mut store, &module, None)?;
+    /// let add = instance.func_untyped(&store, "add")?;
+    /// let result = add.call(&mut store, &[WasmValue::I32(20), WasmValue::I32(22)])?;
+    /// assert_eq!(result, vec![WasmValue::I32(42)]);
+    /// # Ok(())
+    /// # }
+    /// ```
+    ///
+    /// For typed access, see [`Self::func`].
     pub fn func_untyped(&self, store: &Store, name: &str) -> Result<Function> {
         self.validate_store(store)?;
 
@@ -346,7 +386,32 @@ impl ModuleInstance {
     }
 
     /// Get a typed function export by name.
-    pub fn func<P: IntoWasmValueTuple + WasmTypesFromTuple, R: FromWasmValueTuple + WasmTypesFromTuple>(
+    ///
+    /// ## Example
+    /// ```rust
+    /// # fn main() -> tinywasm::Result<()> {
+    /// # use tinywasm::{ModuleInstance, Store};
+    /// # let wasm = wat::parse_str(r#"
+    /// #     (module
+    /// #       (func (export "add") (param i32 i32) (result i32)
+    /// #         local.get 0
+    /// #         local.get 1
+    /// #         i32.add))
+    /// # "#).expect("valid wat");
+    /// # let module = tinywasm::parse_bytes(&wasm)?;
+    /// # let mut store = Store::default();
+    /// let instance = ModuleInstance::instantiate(&mut store, &module, None)?;
+    /// let add = instance.func::<(i32, i32), i32>(&store, "add")?;
+    /// assert_eq!(add.call(&mut store, (20, 22))?, 42);
+    /// # Ok(())
+    /// # }
+    /// ```
+    ///
+    /// For untyped access, see [`Self::func_untyped`] and [`Self::extern_item`].
+    ///
+    /// For signatures that exceed tuple arity 12, see [`crate::WasmTupleChain`], which can be used
+    /// directly as `instance.func::<crate::WasmTupleChain<_, _>, _>(...)`.
+    pub fn func<P: IntoWasmValues + ToWasmTypes, R: FromWasmValues + ToWasmTypes>(
         &self,
         store: &Store,
         name: &str,
@@ -359,10 +424,7 @@ impl ModuleInstance {
     /// Get a typed function by its module-local index.
     #[cfg_attr(docsrs, doc(cfg(feature = "guest-debug")))]
     #[cfg(feature = "guest-debug")]
-    pub fn func_typed_by_index<
-        P: IntoWasmValueTuple + WasmTypesFromTuple,
-        R: FromWasmValueTuple + WasmTypesFromTuple,
-    >(
+    pub fn func_typed_by_index<P: IntoWasmValues + ToWasmTypes, R: FromWasmValues + ToWasmTypes>(
         &self,
         store: &Store,
         func_index: FuncAddr,
@@ -372,10 +434,7 @@ impl ModuleInstance {
         Ok(FunctionTyped { func, marker: core::marker::PhantomData })
     }
 
-    fn validate_typed_func<P: WasmTypesFromTuple, R: WasmTypesFromTuple>(
-        func: &Function,
-        func_name: &str,
-    ) -> Result<()> {
+    fn validate_typed_func<P: ToWasmTypes, R: ToWasmTypes>(func: &Function, func_name: &str) -> Result<()> {
         if *func.ty.params() != *P::wasm_types() || *func.ty.results() != *R::wasm_types() {
             cold_path();
 
diff --git a/crates/tinywasm/src/lib.rs b/crates/tinywasm/src/lib.rs
index 4b6b360..4e9f828 100644
--- a/crates/tinywasm/src/lib.rs
+++ b/crates/tinywasm/src/lib.rs
@@ -107,7 +107,10 @@ pub(crate) mod log {
 
 mod error;
 pub use error::*;
-pub use func::{ExecProgress, FuncContext, FuncExecution, FuncExecutionTyped, Function, FunctionTyped, HostFunction};
+pub use func::{
+    ExecProgress, FuncContext, FuncExecution, FuncExecutionTyped, Function, FunctionTyped, HostFunction, ToWasmTypes,
+    WasmTupleChain,
+};
 pub use imports::*;
 pub use instance::{ExternItem, ModuleInstance};
 pub use reference::*;