Start investigating swigless csharp

.gitignore

@@ -22,4 +22,5 @@ inc/blst_aux.h*
 *bindings/python/*_wrap.c
 *bindings/C#/*_wrap.c
 *bindings/C#/*.exe
+*bindings/C#/*.dll
 __pycache__

min-bindings/C#/Makefile

@@ -1,11 +1,8 @@
 INCLUDE_DIRS = .. ../../min-src ../../inc
 
-test: tests.cs libckzg.so ckzg_swig.cs
-	mcs -langversion:5 -optimize+ tests.cs ckzg_swig.cs -r:System.Numerics.dll
-	mono tests.exe
+test: tests.cs ckzg.dll
+	mcs tests.cs
+	./tests.exe
 
-libckzg.so: c_kzg_4844_wrap.c ../../min-src/c_kzg_4844.o ../../lib/libblst.a
-	clang -O -Wall -shared -fPIC -Wl,-Bsymbolic -I${INCLUDE_PY} ${addprefix -I,${INCLUDE_DIRS}} -o $@ $^
-
-c_kzg_4844_wrap.c ckzg_swig.cs: ../c_kzg_4844.swg
-	swig -DSWIGWORDSIZE64 -O -Wall -csharp -outcurrentdir -namespace ckzg -outfile ckzg_swig.cs $<
+ckzg.dll: ckzg.c ../../min-src/c_kzg_4844.o ../../lib/libblst.a
+	clang -O -Wall -shared ${addprefix -I,${INCLUDE_DIRS}} -o $@ $^

min-bindings/C#/ckzg.c

@@ -0,0 +1,8 @@
+#include <inttypes.h>
+#include <stdio.h>
+#include "c_kzg_4844.h"
+
+uint64_t hello(uint64_t a) {
+  printf("Hello World! %lu\n", a);
+  return 42;
+}

min-bindings/C#/tests.cs

@@ -1,10 +1,17 @@
 using System;
 using System.Text;
-using ckzg;
 
-class PoC {
+class ckzg {
+  [global::System.Runtime.InteropServices.DllImport("ckzg.dll", EntryPoint="hello")]
+  public static extern uint hello(uint a);
+  [global::System.Runtime.InteropServices.DllImport("ckzg.dll", EntryPoint="bytes_to_bls_field_wrap")]
+  public static extern void bytes_to_bls_field(byte[] b);
+}
+
+class tests {
   private static void Main(string[] args)
   {
     Console.WriteLine("OK");
+    Console.WriteLine(ckzg.hello(32));
   }
 }