cl: tagbody + go — 11 new tests (151 eval, 323 total green)

Sentinel-based tagbody: cl-build-tag-map indexes tags by str-normalised key
(handles integer tags); cl-eval-tagbody loops with go-jump restart;
go-tag propagates through cl-eval-body alongside block-return.

lib/common-lisp/eval.sx

@@ -40,6 +40,9 @@
 (define cl-block-return?
   (fn (v) (and (dict? v) (= (get v "cl-type") "block-return"))))
 
+(define cl-go-tag?
+  (fn (v) (and (dict? v) (= (get v "cl-type") "go-tag"))))
+
 (define cl-eval-body
   (fn (forms env)
     (cond
@@ -47,7 +50,7 @@
       ((= (len forms) 1) (cl-eval (nth forms 0) env))
       (:else
         (let ((result (cl-eval (nth forms 0) env)))
-          (if (cl-block-return? result)
+          (if (or (cl-block-return? result) (cl-go-tag? result))
             result
             (cl-eval-body (rest forms) env)))))))
 
@@ -270,6 +273,42 @@
       {:cl-type "function" :builtin-fn (get cl-builtins name)}))
   (keys cl-builtins))
 
+;; ── TAGBODY / GO ─────────────────────────────────────────────────
+
+(define cl-tagbody-tag?
+  (fn (form) (or (string? form) (number? form))))
+
+(define cl-build-tag-map
+  (fn (forms i acc)
+    (if (>= i (len forms))
+      acc
+      (if (cl-tagbody-tag? (nth forms i))
+        (cl-build-tag-map forms (+ i 1)
+          (assoc acc (str (nth forms i)) i))
+        (cl-build-tag-map forms (+ i 1) acc)))))
+
+(define cl-eval-tagbody
+  (fn (args env)
+    (let ((tag-map (cl-build-tag-map args 0 {})))
+      (define run
+        (fn (i)
+          (if (>= i (len args))
+            nil
+            (let ((form (nth args i)))
+              (if (cl-tagbody-tag? form)
+                (run (+ i 1))
+                (let ((result (cl-eval form env)))
+                  (cond
+                    ((cl-go-tag? result)
+                      (let ((target (get result "tag")))
+                        (let ((tkey (str target)))
+                          (if (has-key? tag-map tkey)
+                            (run (get tag-map tkey))
+                            {:cl-type "error" :message (str "No tag: " target)}))))
+                    ((cl-block-return? result) result)
+                    (:else (run (+ i 1))))))))))
+      (run 0))))
+
 ;; ── BLOCK / RETURN-FROM ───────────────────────────────────────────
 
 (define cl-eval-block
@@ -563,6 +602,9 @@
           ((= head "LOCALLY")      (cl-eval-body args env))
           ((= head "EVAL-WHEN")    (cl-eval-eval-when args env))
           ((= head "DEFUN")        (cl-eval-defun args env))
+          ((= head "TAGBODY")      (cl-eval-tagbody args env))
+          ((= head "GO")
+            {:cl-type "go-tag" :tag (nth args 0)})
           ((= head "BLOCK")        (cl-eval-block args env))
           ((= head "RETURN-FROM")  (cl-eval-return-from args env))
           ((= head "RETURN")