[fields] Accept public fields.

Close #191

Author: pfusik

GenC.fu

@@ -3936,6 +3936,16 @@ public class GenC : GenCCpp
 		WriteLine("extern \"C\" {");
 		WriteLine("#endif");
 		WriteTypedefs(program, true);
+		foreach (FuClass klass in program.Classes) {
+			if (!klass.IsPublic)
+				continue;
+			for (FuSymbol? member = klass.First; member != null; member = member.Next) {
+				if (member is FuField field && field.Visibility == FuVisibility.Public) {
+					WriteClass(klass, program);
+					break;
+				}
+			}
+		}
 		CloseStringWriter();
 		WriteNewLine();
 		WriteLine("#ifdef __cplusplus");

Parser.fu

@@ -1069,8 +1069,6 @@ public class FuParser : FuLexer
 			}
 
 			// field
-			if (visibility == FuVisibility.Public)
-				ReportFormerError(line, column, "public".Length, "Field cannot be public");
 			if (callType != FuCallType.Normal)
 				ReportCallTypeError(callTypeLine, callTypeColumn, "Field", callType);
 			if (type == this.Host.Program.System.VoidType)

doc/reference.md

@@ -636,20 +636,6 @@ class Point
 }
 ```
 
-Fields _cannot be_ public. Instead, define _getter/setter_ methods:
-
-```csharp
-public class Image
-{
-    int Width;
-    public int GetWidth() { return Width; }
-    public int SetWidth!(int value) { Width = value; }
-
-    int Height;
-    public int GetHeight() => Height; // syntax sugar
-}
-```
-
 Fields _cannot be_ static. Shared state poses problems with lifetime
 and multithreading.
 

libfut.cpp

@@ -4390,8 +4390,6 @@ void FuParser::parseClass(std::shared_ptr<FuCodeDoc> doc, int line, int column,
 				this->foundName = method.get();
 			continue;
 		}
-		if (visibility == FuVisibility::public_)
-			reportFormerError(line, column, 6, "Field cannot be public");
 		if (callType != FuCallType::normal)
 			reportCallTypeError(callTypeLine, callTypeColumn, "Field", callType);
 		if (type == this->host->program->system->voidType)
@@ -13471,6 +13469,17 @@ void GenC::writeProgram(const FuProgram * program, std::string_view outputFile,
 	writeLine("extern \"C\" {");
 	writeLine("#endif");
 	writeTypedefs(program, true);
+	for (const FuClass * klass : program->classes) {
+		if (!klass->isPublic)
+			continue;
+		for (const FuSymbol * member = klass->first; member != nullptr; member = member->next) {
+			const FuField * field;
+			if ((field = dynamic_cast<const FuField *>(member)) && field->visibility == FuVisibility::public_) {
+				writeClass(klass, program);
+				break;
+			}
+		}
+	}
 	closeStringWriter();
 	writeNewLine();
 	writeLine("#ifdef __cplusplus");

libfut.cs

@@ -4654,8 +4654,6 @@ void ParseClass(FuCodeDoc doc, int line, int column, bool isPublic, FuCallType c
 						this.FoundName = method;
 					continue;
 				}
-				if (visibility == FuVisibility.Public)
-					ReportFormerError(line, column, 6, "Field cannot be public");
 				if (callType != FuCallType.Normal)
 					ReportCallTypeError(callTypeLine, callTypeColumn, "Field", callType);
 				if (type == this.Host.Program.System.VoidType)
@@ -13686,6 +13684,16 @@ public override void WriteProgram(FuProgram program, string outputFile, string n
 			WriteLine("extern \"C\" {");
 			WriteLine("#endif");
 			WriteTypedefs(program, true);
+			foreach (FuClass klass in program.Classes) {
+				if (!klass.IsPublic)
+					continue;
+				for (FuSymbol member = klass.First; member != null; member = member.Next) {
+					if (member is FuField field && field.Visibility == FuVisibility.Public) {
+						WriteClass(klass, program);
+						break;
+					}
+				}
+			}
 			CloseStringWriter();
 			WriteNewLine();
 			WriteLine("#ifdef __cplusplus");

libfut.js

@@ -4878,8 +4878,6 @@ export class FuParser extends FuLexer
 					this.#foundName = method;
 				continue;
 			}
-			if (visibility == FuVisibility.PUBLIC)
-				this.#reportFormerError(line, column, 6, "Field cannot be public");
 			if (callType != FuCallType.NORMAL)
 				this.#reportCallTypeError(callTypeLine, callTypeColumn, "Field", callType);
 			if (type == this.host.program.system.voidType)
@@ -14181,6 +14179,17 @@ export class GenC extends GenCCpp
 		this.writeLine("extern \"C\" {");
 		this.writeLine("#endif");
 		this.writeTypedefs(program, true);
+		for (const klass of program.classes) {
+			if (!klass.isPublic)
+				continue;
+			for (let member = klass.first; member != null; member = member.next) {
+				let field;
+				if ((field = member) instanceof FuField && field.visibility == FuVisibility.PUBLIC) {
+					this.writeClass(klass, program);
+					break;
+				}
+			}
+		}
 		this.closeStringWriter();
 		this.writeNewLine();
 		this.writeLine("#ifdef __cplusplus");

test/ObjectFieldPublic.fu

@@ -0,0 +1,14 @@
+public class Foo
+{
+	public int Bar;
+}
+
+public static class Test
+{
+	public static bool Run()
+	{
+		Foo() o;
+		o.Bar = 42;
+		return o.Bar == 42;
+	}
+}