enums and match (in the compiler written in Finch)

enum Color { Red, Green, Blue }   enum Status { Ok = 200, NotFound = 404 }

Color.Red, Color(n) (checked), int(c), == and != only, printed by name, usable as
map keys and struct fields, with methods (fn Color.next()).

match value { Red, Green -> ... Blue -> ... else -> ... } as a statement, or as an
expression that gives a value. Works on enums, whole numbers, chars, text and bools;
a match on an enum has to handle every variant or end with else, and says which are
missing. A bare variant name (Red) is enough inside a match on an enum.

Only the self-hosted compiler has them; tests/new holds their tests, tests/run stays what
the C++ compiler also runs. boot.sh: 31 passed.

boot/ast.fch

@@ -40,7 +40,7 @@ fn same(Type a, Type b) -> bool {
     if a.kind != b.kind {
         return false
     }
-    if a.kind == "struct" || a.kind == "named" {
+    if a.kind == "struct" || a.kind == "named" || a.kind == "enum" {
         return a.name == b.name && a.module == b.module
     }
     if a.kind == "fixed" && a.count != b.count {
@@ -76,7 +76,7 @@ fn show(Type t) -> str {
         }
         return "ptr[" + show(t.elem[0]) + "]"
     }
-    if t.kind == "struct" || t.kind == "named" {
+    if t.kind == "struct" || t.kind == "named" || t.kind == "enum" {
         if t.module.len > 0 {
             return t.module + "." + t.name
         }
@@ -91,7 +91,8 @@ fn show(Type t) -> str {
 // One node of the tree, for expressions, statements, functions and structs alike.
 //   expressions: int float str char bool null var unary binary call member index array method
 //   statements:  decl assign expr if while for each return break continue block
-//   top level:   fn param struct field
+//   top level:   fn param struct field enum variant
+//   match:       match (kids: subject, arms...), arm (kids: patterns node, body; flag: the else arm), patterns
 struct Node {
     str kind
     str name      // identifier, operator, callee, field or method name
@@ -115,5 +116,6 @@ struct Program {
     []str cwhere    // where each was written, for error messages
     []str links     // link "glfw", link "mine.c"
     []Node structs
+    []Node enums
     []Node fns
 }