Auto-generate C# ModuleDef bindings from Rust (#1680)

Author: RReverser

.gitattributes

@@ -1,2 +1,3 @@
 **/module_bindings/** linguist-generated=true eol=lf
 *.verified.cs linguist-generated=true eol=lf
+/crates/bindings-csharp/Runtime/Internal/Autogen/*.cs linguist-generated=true

Cargo.lock

@@ -27,14 +27,10 @@ IEnumerable<MemberDeclaration> members
     }
 
     public static string GenerateDefs(IEnumerable<MemberDeclaration> members) =>
-        $$"""
-        new SpacetimeDB.BSATN.AggregateElement[] {
-            {{string.Join(
-                ",\n",
-                members.Select(m => $"new(nameof({m.Name}), {m.Name}.GetAlgebraicType(registrar))")
-            )}}
-        }
-        """;
+        string.Join(
+            ",\n",
+            members.Select(m => $"new(nameof({m.Name}), {m.Name}.GetAlgebraicType(registrar))")
+        );
 }
 
 public enum TypeKind
@@ -230,9 +226,9 @@ public void Write(System.IO.BinaryWriter writer, {{ShortName}} value) {
                 }
 
                 public SpacetimeDB.BSATN.AlgebraicType GetAlgebraicType(SpacetimeDB.BSATN.ITypeRegistrar registrar) =>
-                    registrar.RegisterType<{{ShortName}}>(_ => new SpacetimeDB.BSATN.AlgebraicType.{{Kind}}(
+                    registrar.RegisterType<{{ShortName}}>(_ => new SpacetimeDB.BSATN.AlgebraicType.{{Kind}}(new SpacetimeDB.BSATN.AggregateElement[] {
                         {{MemberDeclaration.GenerateDefs(Members)}}
-                    ));
+                    }));
             }
             """
         );

crates/bindings-csharp/BSATN.Codegen/Type.cs

@@ -23,16 +23,17 @@ public static void Initialize()
                     unformattedCode,
                     new() { IncludeGenerated = true, EndOfLine = CSharpier.EndOfLine.LF }
                 );
+                sb.Append(result.Code);
+                // Print errors in the end so that their line numbers are still meaningful.
                 if (result.CompilationErrors.Any())
                 {
+                    sb.AppendLine();
                     sb.AppendLine("// Generated code produced compilation errors:");
                     foreach (var diag in result.CompilationErrors)
                     {
                         sb.Append("// ").AppendLine(diag.ToString());
                     }
-                    sb.AppendLine();
                 }
-                sb.Append(result.Code);
             },
             ScrubberLocation.Last
         );