replace i31 stack result fun with exception variant

executor/invoker/src/commonMain/kotlin/io/github/charlietap/chasm/executor/invoker/instruction/aggregate/I31GetSignedExecutor.kt

@@ -1,13 +1,11 @@
 package io.github.charlietap.chasm.executor.invoker.instruction.aggregate
 
-import io.github.charlietap.chasm.executor.invoker.ext.bind
 import io.github.charlietap.chasm.executor.runtime.execution.ExecutionContext
 import io.github.charlietap.chasm.executor.runtime.ext.extendSigned
 import io.github.charlietap.chasm.executor.runtime.ext.extendUnsigned
 import io.github.charlietap.chasm.executor.runtime.ext.popI31Reference
 import io.github.charlietap.chasm.executor.runtime.instruction.AggregateInstruction
 import io.github.charlietap.chasm.executor.runtime.value.NumberValue
-import io.github.charlietap.chasm.executor.runtime.value.ReferenceValue
 
 internal fun I31GetSignedExecutor(
     context: ExecutionContext,
@@ -16,19 +14,19 @@ internal fun I31GetSignedExecutor(
     I31GetExecutor(
         context = context,
         signedExtension = true,
-        i31SignedExtender = ReferenceValue.I31::extendSigned,
-        i31UnsignedExtender = ReferenceValue.I31::extendUnsigned,
+        i31SignedExtender = UInt::extendSigned,
+        i31UnsignedExtender = UInt::extendUnsigned,
     )
 
 internal inline fun I31GetExecutor(
     context: ExecutionContext,
     signedExtension: Boolean,
-    crossinline i31SignedExtender: (ReferenceValue.I31) -> Int,
-    crossinline i31UnsignedExtender: (ReferenceValue.I31) -> Int,
+    crossinline i31SignedExtender: (UInt) -> Int,
+    crossinline i31UnsignedExtender: (UInt) -> Int,
 ) {
 
     val (stack) = context
-    val value = stack.popI31Reference().bind()
+    val value = stack.popI31Reference()
 
     val extended = if (signedExtension) {
         i31SignedExtender(value)

executor/invoker/src/commonMain/kotlin/io/github/charlietap/chasm/executor/invoker/instruction/aggregate/I31GetUnsignedExecutor.kt

@@ -4,7 +4,6 @@ import io.github.charlietap.chasm.executor.runtime.execution.ExecutionContext
 import io.github.charlietap.chasm.executor.runtime.ext.extendSigned
 import io.github.charlietap.chasm.executor.runtime.ext.extendUnsigned
 import io.github.charlietap.chasm.executor.runtime.instruction.AggregateInstruction
-import io.github.charlietap.chasm.executor.runtime.value.ReferenceValue
 
 internal fun I31GetUnsignedExecutor(
     context: ExecutionContext,
@@ -13,6 +12,6 @@ internal fun I31GetUnsignedExecutor(
     I31GetExecutor(
         context = context,
         signedExtension = false,
-        i31SignedExtender = ReferenceValue.I31::extendSigned,
-        i31UnsignedExtender = ReferenceValue.I31::extendUnsigned,
+        i31SignedExtender = UInt::extendSigned,
+        i31UnsignedExtender = UInt::extendUnsigned,
     )

executor/invoker/src/commonTest/kotlin/io/github/charlietap/chasm/executor/invoker/instruction/aggregate/I31GetExecutorTest.kt

@@ -1,7 +1,6 @@
 package io.github.charlietap.chasm.executor.invoker.instruction.aggregate
 
 import io.github.charlietap.chasm.executor.invoker.fixture.executionContext
-import io.github.charlietap.chasm.executor.runtime.value.ReferenceValue
 import io.github.charlietap.chasm.fixture.executor.runtime.stack
 import io.github.charlietap.chasm.fixture.executor.runtime.value.i31ReferenceValue
 import io.github.charlietap.chasm.fixture.executor.runtime.value.i32
@@ -22,12 +21,12 @@ class I31GetExecutorTest {
 
         stack.push(i31)
 
-        val i31SignedExtender: (ReferenceValue.I31) -> Int = { input ->
-            assertEquals(i31, input)
+        val i31SignedExtender: (UInt) -> Int = { input ->
+            assertEquals(i31.value, input)
             i32
         }
 
-        val i31UnsignedExtender: (ReferenceValue.I31) -> Int = { _ ->
+        val i31UnsignedExtender: (UInt) -> Int = { _ ->
             fail("Unsigned extender should not be called in this scenario")
         }
 
@@ -48,12 +47,12 @@ class I31GetExecutorTest {
 
         stack.push(i31)
 
-        val i31SignedExtender: (ReferenceValue.I31) -> Int = { _ ->
+        val i31SignedExtender: (UInt) -> Int = { _ ->
             fail("Unsigned extender should not be called in this scenario")
         }
 
-        val i31UnsignedExtender: (ReferenceValue.I31) -> Int = { input ->
-            assertEquals(i31, input)
+        val i31UnsignedExtender: (UInt) -> Int = { input ->
+            assertEquals(i31.value, input)
             i32
         }
 

executor/runtime-internal/src/commonMain/kotlin/io/github/charlietap/chasm/executor/runtime/error/InvocationError.kt

@@ -101,6 +101,8 @@ sealed interface InvocationError : ModuleTrapError {
 
     data object ArrayReferenceExpected : InvocationError
 
+    data object I31ReferenceExpected : InvocationError
+
     data object UnexpectedReferenceValue : InvocationError
 
     data object UndefinedDefaultBottomType : InvocationError

executor/runtime-internal/src/commonMain/kotlin/io/github/charlietap/chasm/executor/runtime/ext/StackExt.kt

@@ -101,10 +101,12 @@ inline fun Stack.peekReference(): ReferenceValue {
     }
 }
 
-inline fun Stack.popI31Reference(): Result<ReferenceValue.I31, InvocationError.MissingStackValue> {
-    return (popValue() as? ReferenceValue.I31)?.let {
-        Ok(it)
-    } ?: Err(InvocationError.MissingStackValue)
+inline fun Stack.popI31Reference(): UInt {
+    return try {
+        (popValue() as ReferenceValue.I31).value
+    } catch (_: ClassCastException) {
+        throw InvocationException(InvocationError.I31ReferenceExpected)
+    }
 }
 
 inline fun Stack.popArrayReference(): ArrayInstance {

executor/runtime-internal/src/commonMain/kotlin/io/github/charlietap/chasm/executor/runtime/ext/UIntExt.kt

@@ -0,0 +1,12 @@
+package io.github.charlietap.chasm.executor.runtime.ext
+
+inline fun UInt.extendSigned(): Int {
+    val signBit = 1 shl 30
+    return if ((this and signBit.toUInt()) != 0u) {
+        this.toInt() or (Int.MIN_VALUE)
+    } else {
+        this.toInt()
+    }
+}
+
+inline fun UInt.extendUnsigned(): Int = this.toInt()