Immutability and strip the / off the path

x) Better path substring
x) Add some interfaces for immutability

imm/FSM.cs

@@ -10,15 +10,17 @@ namespace imm;
 
 
 
-public record class Context : imm.Recorded<Context>
+public record class Context : imm.Recorded<Context>, Imm
 {
-
+	Meta Imm.Meta => base.Meta;
 }
 
-public record class State<TSUB, CTX>( CTX Context ) : imm.Recorded<TSUB>
+public record class State<TSUB, CTX>( CTX Context ) : imm.Recorded<TSUB>, Imm
 	where TSUB : State<TSUB, CTX>
 	where CTX : Context
 {
+	Meta Imm.Meta => base.Meta;
+
 	virtual public (CTX, TSUB) onEnter(CTX ctx, State<TSUB, CTX> oldState)
 	{
 		return (ctx, (TSUB)this);
@@ -32,11 +34,13 @@ public record class State<TSUB, CTX>( CTX Context ) : imm.Recorded<TSUB>
 
 
 
-public record class FSM<TSUB, ST, CTX> : imm.Recorded<TSUB>
+public record class FSM<TSUB, ST, CTX> : imm.Recorded<TSUB>, Imm
 	where TSUB : FSM<TSUB, ST, CTX>
 	where ST : State<ST, CTX>
 	where CTX : Context
 {
+	Meta Imm.Meta => base.Meta;
+
 	public CTX Context { get; init; }
 	public ST State { get; init; }
 

imm/Imm.cs

@@ -49,13 +49,32 @@ static public class Util
 	}
 }
 
+public interface Meta
+{
+		public uint   Version => 0;
+		public string Reason => "";
+		public string Expression => "";
+		public string MemberName => "";
+		public string FilePath => "";
+		public int    LineNumber => -1;
+		public DateTime CreatedAt => DateTime.MinValue;
+		public DateTime TouchedAt => DateTime.MinValue;
+
+}
+
+
+public interface Imm
+{
+	public Meta Meta { get; }
+}
+
 //[lib.Ser( Types = lib.Types.None )]
-public record class Versioned<T>
+public record class Versioned<T> : Imm
 	where T : Versioned<T>
 {
 	public delegate void ChangeDelegate( T ZZOld, T next );
 
-	public record class MetaData
+	public record class MetaData : Meta
 	{
 		public uint Version { get; internal set; } = 0;
 		public string Reason { get; internal set; } = "";
@@ -78,6 +97,8 @@ public record class Versioned<T>
 	[DebuggerBrowsable(DebuggerBrowsableState.Never)]
 	public MetaData Meta => MetaStorage;
 
+	Meta Imm.Meta => MetaStorage;
+
 	[lib.Dont]
 	[DebuggerBrowsable(DebuggerBrowsableState.Never)]
 	public ChangeDelegate OnChange = (x, y) => {};

imm/iu.cs

@@ -21,7 +21,7 @@ static public class iu
 													[CallerLineNumber] int lineNumber = 0,
 													[CallerArgumentExpression("fn")]
 													string expression = default )
-		where T : Recorded<T>
+		where T : Recorded<T>, Imm
 	{
 		obj = obj.Process( fn, reason, memberName, filePath, lineNumber, expression );
 		return obj;
@@ -34,7 +34,7 @@ static public class iu
 													[CallerLineNumber] int lineNumber = 0,
 													[CallerArgumentExpression("fn")]
 													string expression = default )
-		where T : Recorded<T>
+		where T : Recorded<T>, Imm
 	{
 		obj = obj.Process( fn, reason, memberName, filePath, lineNumber, expression );
 		return obj;
@@ -48,7 +48,7 @@ static public class iu
 													[CallerLineNumber] int lineNumber = 0,
 													[CallerArgumentExpression("fn")]
 													string expression = default )
-		where T : Versioned<T>
+		where T : Versioned<T>, Imm
 	{
 		obj = obj.Process( fn, reason );
 		return obj;

logging/Log.cs

@@ -176,11 +176,16 @@ static public class log
 	{
 		var cwd = Directory.GetCurrentDirectory();
 
-		var rel = fullPath.Substring( cwd.Length );
+		var rel = fullPath.Substring( cwd.Length + 1 );
 
 		return rel;
 	}
 
+	static public string thisFilePath( [CallerFilePath] string path = "" )
+	{
+		return relativePath( path );
+	}
+
 	// Forwards.
 	static public void fatal( string msg, string cat = "", object obj = null, [CallerFilePath] string path = "", [CallerLineNumber] int line = -1, [CallerMemberName] string member = "" )
 	{