document Backtrace

TODO

@@ -6,17 +6,13 @@ Types:
     Date        # probably possible to steal much from S32::Temporal
     DateTime    # probably possible to steal much from S32::Temporal
 
-    Backtrace
-    Backtrace::Frame
-
     Bag
     Set
     KeyBag
     KeySet
 
     Order (enum)
 
-    Signature
     Parameter
 
     Junction

lib/Backtrace.pod

@@ -0,0 +1,40 @@
+=begin pod
+
+=TITLE class Backtrace
+
+    class Backtrace is List { ... }
+
+A backtrace shows the dynamic call stack, usually leading up to a point
+where an exception was thrown.
+
+It is a List of L<Backtrace::Frame> objects. Its default stringification
+excludes backtrace frames that are deemed unnecessary or confusing, for
+example routines like C<&die> are hidden by default.
+
+=head1 Methods
+
+=head2 new
+
+    proto method new(*@, *%) {*}
+    multi method new()
+
+Creates a new backtrace, using its calling location as the origin of the
+backtrace.
+
+=head2 Str
+
+    multi method Str(Backtrace:D:) returns Str:D:
+
+Returns a concise string representation of the backtrace, omitting
+routines marked as C<is hidden_from_backtrace>, and at the discretion of
+the implementor, also some routines from the setting.
+
+=head2 full
+
+
+    multi method full(Backtrace:D:) returns Str:D:
+
+Returns a full string representation of the backtrace, including hidden
+frames, compiler-specific frames and those from the setting.
+
+=end pod