MVP for higher order functions (#2849)

* MVP for higher order functions

* Add shader subgroup partitioned glsl intrinsics

* Implement parsing and checking for tuple types

Currently there is no way to do anything useful with them from the source language however

* neaten

* Correct precedence of function type parsing

* neaten

* higher order function tests

* function types of any arity

* Inference for higher order functions

* Add second test for unsynchronized params

* regenerate vs projects

* dx11 -> dx12 for saturated cooperations tests

* Disable saturated cooperation tests on vulkan

They fail on release builds in CI, not essential for the higher order function work however

* remove saturated-cooperation tests

* Remove unnecessary assert and clarify control flow in AddDeclRefOverloadCandidates

* Add Tuple type name mangling

* Use functype keyword to introduce function types

* Add more inference tests for hof

---------

Co-authored-by: Yong He <yonghe@outlook.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/tests/language-feature/higher-order-functions/simple.slang b/tests/language-feature/higher-order-functions/simple.slang
new file mode 100644
index 000000000..7c6bf5a26
--- /dev/null
+++ b/tests/language-feature/higher-order-functions/simple.slang
@@ -0,0 +1,31 @@
+//TEST(compute, vulkan):COMPARE_COMPUTE_EX():-vk -compute -shaderobj -output-using-type
+//TEST(compute):COMPARE_COMPUTE_EX():-slang -compute -shaderobj -output-using-type
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name=outputBuffer
+RWStructuredBuffer<uint> outputBuffer;
+
+func twice<A>(f : functype (A) -> A, a : A) -> A
+{
+    return f(f(a));
+}
+
+func apply2<A, B, C>(f : functype (A, B) -> C, a : A, b : B) -> C
+{
+    return f(a, b);
+}
+
+func multiply(x : float, y : float) -> float
+{
+    return x * y;
+}
+
+func square(x : float) -> float
+{
+    return apply2<float, float, float>(multiply, x, x);
+}
+
+[numthreads(4, 1, 1)]
+void computeMain(uint tig : SV_GroupIndex)
+{
+    outputBuffer[tig] = uint(twice(square, -2.f));
+}