cl: multiple values — 15 new tests (174 eval, 346 total green)

VALUES wraps 2+ values in {:cl-type "mv"}; cl-mv-primary strips to
primary in IF/AND/OR/COND/cl-call-fn single-value contexts; cl-mv-vals
expands for MULTIPLE-VALUE-BIND, MULTIPLE-VALUE-CALL, NTH-VALUE.

lib/common-lisp/tests/eval.sx

@@ -388,3 +388,51 @@
 (cl-test "unwind-protect: nested, inner cleanup first"
   (ev "(let ((n 0)) (unwind-protect (unwind-protect 1 (setq n (+ n 10))) (setq n (+ n 1))) n)")
   11)
+
+;; ── VALUES / MULTIPLE-VALUE-BIND / NTH-VALUE ────────────────────
+
+(cl-test "values: single returns plain"
+  (ev "(values 42)")
+  42)
+(cl-test "values: zero returns nil"
+  (ev "(values)")
+  nil)
+(cl-test "values: multi — primary via funcall"
+  (ev "(car (list (values 1 2)))")
+  1)
+(cl-test "multiple-value-bind: basic"
+  (ev "(multiple-value-bind (a b) (values 1 2) (+ a b))")
+  3)
+(cl-test "multiple-value-bind: extra vars get nil"
+  (ev "(multiple-value-bind (a b c) (values 10 20) (list a b c))")
+  (list 10 20 nil))
+(cl-test "multiple-value-bind: extra values ignored"
+  (ev "(multiple-value-bind (a) (values 1 2 3) a)")
+  1)
+(cl-test "multiple-value-bind: single value source"
+  (ev "(multiple-value-bind (a b) 42 (list a b))")
+  (list 42 nil))
+(cl-test "nth-value: 0"
+  (ev "(nth-value 0 (values 10 20 30))")
+  10)
+(cl-test "nth-value: 1"
+  (ev "(nth-value 1 (values 10 20 30))")
+  20)
+(cl-test "nth-value: out of range"
+  (ev "(nth-value 5 (values 10 20))")
+  nil)
+(cl-test "multiple-value-call: basic"
+  (ev "(multiple-value-call #'+ (values 1 2) (values 3 4))")
+  10)
+(cl-test "multiple-value-prog1: returns first"
+  (ev "(multiple-value-prog1 1 2 3)")
+  1)
+(cl-test "multiple-value-prog1: side effects run"
+  (ev "(let ((x 0)) (multiple-value-prog1 99 (setq x 7)) x)")
+  7)
+(cl-test "values: nil primary in if"
+  (ev "(if (values nil t) 'yes 'no)")
+  "NO")
+(cl-test "values: truthy primary in if"
+  (ev "(if (values 42 nil) 'yes 'no)")
+  "YES")