erlang: try/catch/of/after, Phase 4 complete (+19 tests)

lib/erlang/tests/eval.sx

@@ -561,6 +561,79 @@
   (nm (ev "P = spawn(fun () -> exit(boom) end), monitor(process, P), receive {'DOWN', _, _, _, _} -> alive end"))
   "alive")
 
+;; ── try / catch / of / after ─────────────────────────────────
+(er-eval-test "try plain"
+  (ev "try 1 + 2 catch _ -> oops end") 3)
+
+(er-eval-test "try throw caught"
+  (nm (ev "try throw(boom) catch throw:X -> X end")) "boom")
+(er-eval-test "try error caught"
+  (nm (ev "try error(crash) catch error:X -> X end")) "crash")
+(er-eval-test "try exit caught"
+  (nm (ev "try exit(quit) catch exit:X -> X end")) "quit")
+
+(er-eval-test "default class is throw"
+  (nm (ev "try throw(bye) catch X -> X end")) "bye")
+(er-eval-test "default class doesn't catch error"
+  (do
+    (ev "P = spawn(fun () -> try error(crash) catch X -> X end end), receive after 0 -> ok end")
+    (nm (er-proc-field (er-mk-pid 1) :exit-reason)))
+  "crash")
+
+;; of clauses
+(er-eval-test "try of single"
+  (ev "try 42 of N -> N * 2 catch _ -> 0 end") 84)
+(er-eval-test "try of multi"
+  (nm (ev "try ok of ok -> matched; _ -> nope catch _ -> oops end"))
+  "matched")
+(er-eval-test "try of fallthrough"
+  (nm (ev "try x of ok -> a; error -> b; _ -> default catch _ -> oops end"))
+  "default")
+(er-eval-test "try of with guard"
+  (nm (ev "try 5 of N when N > 0 -> pos; _ -> nonneg catch _ -> oops end"))
+  "pos")
+
+;; after clause
+(er-eval-test "after on success"
+  (do (er-io-flush!)
+    (ev "try 7 after io:format(\"a\") end")
+    (er-io-buffer-content))
+  "a")
+(er-eval-test "after on caught"
+  (do (er-io-flush!)
+    (ev "try throw(b) catch throw:_ -> caught after io:format(\"x\") end")
+    (er-io-buffer-content))
+  "x")
+(er-eval-test "after returns body value"
+  (ev "try 99 after 0 end") 99)
+(er-eval-test "try preserves catch result"
+  (nm (ev "try throw(x) catch throw:_ -> recovered after 0 end"))
+  "recovered")
+
+;; nested try
+(er-eval-test "try nested catch outer"
+  (nm (ev "try (try throw(inner) catch error:_ -> bad end) catch throw:X -> X end"))
+  "inner")
+(er-eval-test "try nested catch inner"
+  (nm (ev "try (try throw(inner) catch throw:X -> X end) catch _ -> outer end"))
+  "inner")
+
+;; class re-raise on no-match
+(er-eval-test "throw without catch-throw escapes"
+  (do
+    (ev "P = spawn(fun () -> try throw(bye) catch error:_ -> nope end end), receive after 0 -> ok end")
+    (let ((reason (er-proc-field (er-mk-pid 1) :exit-reason)))
+      (and (er-tuple? reason) (nm (nth (get reason :elements) 0)))))
+  "nocatch")
+
+;; multi-clause catch
+(er-eval-test "multi-clause catch picks throw"
+  (nm (ev "try throw(a) catch error:X -> e; throw:X -> t; exit:X -> x end"))
+  "t")
+(er-eval-test "multi-clause catch picks exit"
+  (nm (ev "try exit(a) catch error:X -> e; throw:X -> t; exit:X -> x end"))
+  "x")
+
 (define
   er-eval-test-summary
   (str "eval " er-eval-test-pass "/" er-eval-test-count))