Add functor syntax support. (#4926)

3 files changed, 47 insertions, 7 deletions

diff --git a/tests/language-feature/ifunc/diff-functor.slang b/tests/language-feature/ifunc/diff-functor.slang
index 04b0be44f..117cce76b 100644
--- a/tests/language-feature/ifunc/diff-functor.slang
+++ b/tests/language-feature/ifunc/diff-functor.slang
@@ -6,7 +6,7 @@
 struct DiffFunctor : IDifferentiableFunc<float, float>
 {
     [Differentiable]
-    float __call(float p)
+    float operator()(float p)
     {
         return p + 1;
     }
@@ -14,19 +14,19 @@ struct DiffFunctor : IDifferentiableFunc<float, float>
 
 float apply(IMutatingFunc<float, float> f, float p)
 {
-    return f.__call(p);
+    return f(p);
 }
 
 [Differentiable]
 float applyDiff(IDifferentiableFunc<float, float> f, float p)
 {
-    return f.__call(p);
+    return f(p);
 }
 
 [Differentiable]
 TR applyDiffGen<TR : IDifferentiable, each TP : IDifferentiable>(IDifferentiableFunc<TR, TP> f, expand each TP p)
 {
-    return f.__call(expand each p);
+    return f(expand each p);
 }
 
 //TEST_INPUT:ubuffer(data=[0 3 2 2], stride=4):out,name=outputBuffer
diff --git a/tests/language-feature/ifunc/functor.slang b/tests/language-feature/ifunc/functor.slang
new file mode 100644
index 000000000..73987cbbf
--- /dev/null
+++ b/tests/language-feature/ifunc/functor.slang
@@ -0,0 +1,40 @@
+//TEST(compute):COMPARE_COMPUTE(filecheck-buffer=CHECK):-shaderobj -output-using-type
+//TEST(compute):COMPARE_COMPUTE(filecheck-buffer=CHECK):-dx12 -use-dxil -shaderobj -output-using-type
+//TEST(compute):COMPARE_COMPUTE(filecheck-buffer=CHECK):-cpu -shaderobj -output-using-type
+//TEST(compute):COMPARE_COMPUTE(filecheck-buffer=CHECK):-vk -shaderobj -output-using-type
+
+struct Functor : IMutatingFunc<float, float>
+{
+    int context;
+
+    [mutating]
+    float operator()(float p)
+    {
+        context += (int)p;
+        return context;
+    }
+}
+
+float apply<T:IMutatingFunc<float,float>>(inout T f, float p)
+{
+    return f(p);
+}
+
+//TEST_INPUT:ubuffer(data=[0 3 2 2], stride=4):out,name=outputBuffer
+RWStructuredBuffer<uint> outputBuffer;
+
+[numthreads(1, 1, 1)]
+void computeMain(uint tid: SV_DispatchThreadID)
+{
+    Functor f;
+    f.context = 0;
+    
+    f(1.0f);
+    f.operator()(1.0f); // explicit operator () call should also work.
+
+    apply(f, 2.0f);
+    apply(f, 3.0f);
+
+    // CHECK: 7
+    outputBuffer[0] = (uint)f.context;
+}
diff --git a/tests/language-feature/ifunc/ifunc.slang b/tests/language-feature/ifunc/ifunc.slang
index f270299b3..6c946f4df 100644
--- a/tests/language-feature/ifunc/ifunc.slang
+++ b/tests/language-feature/ifunc/ifunc.slang
@@ -5,7 +5,7 @@
 
 struct Functor : IFunc<int, int, bool>
 {
-    int __call(int p, bool t)
+    int operator()(int p, bool t)
     {
         return p + 1;
     }
@@ -15,7 +15,7 @@ struct MutatingFunctor : IMutatingFunc<int, int, bool>
 {
     int data = 0;
     [mutating]
-    int __call(int p, bool t)
+    int operator()(int p, bool t)
     {
         data++;
         return p + 1;
@@ -24,7 +24,7 @@ struct MutatingFunctor : IMutatingFunc<int, int, bool>
 
 int apply(IMutatingFunc<int, int, bool> f, int p)
 {
-    return f.__call(p, true);
+    return f(p, true);
 }
 
 //TEST_INPUT:ubuffer(data=[0 3 2 2], stride=4):out,name=outputBuffer