accept pub enum, and enums used as types

Implement pub support for enums, and also anonymous enums declared
in-place.

Also give the cdr of a `pub' form the form's own location, so a
error about what follows `pub' can say where it was written

tests/codegen.scm

@@ -141,6 +141,28 @@ compiles."
     (test-assert "a comment in a body stays in the body"
       (emits? (in-fn "(while (< a b) ;; inside\n (g 1))")
               "while (a < b) {")))
+
+  (test-group "pub enum"
+    (test-assert "is emitted"
+      (emits? "(pub enum color (red green blue))" "enum color"))
+    (test-assert "with its values"
+      (emits? "(pub enum color (red green blue))" "red"))
+    (test-assert "and a non-pub enum still is too"
+      (emits? "(enum color (red green blue))" "enum color"))
+    ;; Naming an enum as a type, rather than defining it, had no
+    ;; walk-enum clause and died with `(match) no matching pattern'
+    (test-assert "and it can then be used as a type"
+      (emits? "(enum color (red green blue)) (fn f () void (var m (enum color) red))"
+              "enum color m = red"))
+    (test-assert "a malformed enum is rejected with its location"
+      (reports? "(enum)" "codegen.sex:1:"))
+    ;; c-type handed the declarator's name to c-enum as the enum tag,
+    ;; so this emitted `enum m { up, down }' with no variable at all
+    (test-assert "an anonymous enum keeps the variable"
+      (emits? "(fn f () void (var e (enum (up down)) up))" "} e = up"))
+    (test-assert "and a named definition keeps both"
+      (emits? "(fn f () void (var n (enum named (a b)) a))" "enum named{")))
+
   ;; `|', `||' and `|=' read as ordinary symbols -- our own reader has
   ;; no |symbol| syntax for them to collide with -- but fmt-c cannot
   ;; dispatch on a symbol whose name it cannot write in Scheme source,

tests/modules/Makefile

@@ -14,7 +14,7 @@
 
 SEXC ?= ../../sexc
 
-EXPECTED = hello, world\nhello, sex\n2 greetings\ntext times 
+EXPECTED = hello, world\nhello, sex\n2 greetings\ntext times \nmood 1
 
 check:
 	@$(SEXC) greet.sex -c -o greet.o

tests/modules/greet-app.sex

@@ -21,4 +21,6 @@
   (printf "%d greetings\n" greet-count)
   (describe-fields greeting)
   (printf "\n")
+  (var m (enum mood) grumpy)
+  (printf "mood %d\n" m)
   (return 0))

tests/modules/greet.sex

@@ -11,6 +11,8 @@
 
 (pub struct greeting ((text (* const char)) (times int)))
 
+(pub enum mood (cheerful grumpy))
+
 ;;; Compile-time reflection across the module boundary: both the macro
 ;;; and the struct it asks about are exported, and the importing unit
 ;;; has to know the struct's fields to expand this.