Forbid (try) and (try BODY)

NEWS

@@ -12,6 +12,7 @@ Changes from 0.12.1
      follow all `except`s, and `finally` must come last). This is only a
      syntactic change; the elements were already run in Python order even when
      defined out of order.
+   * `try` now requires an `except` or `finally` clause, as in Python
    * Importing or executing a Hy file automatically byte-compiles it, or loads
      a byte-compiled version if it exists and is up to date. This brings big
      speed boosts, even for one-liners, because Hy no longer needs to recompile

hy/compiler.py

@@ -819,17 +819,11 @@ class HyASTCompiler(object):
             raise HyTypeError(
                 expr,
                 "`try' cannot have `else' without `except'")
-
-        # (try) or (try BODY)
-        # Generate a default handler for Python >= 3.3 and pypy
-        if not handlers and not finalbody and not orelse:
-            handlers = [ast.ExceptHandler(
-                lineno=expr.start_line,
-                col_offset=expr.start_column,
-                type=None,
-                name=None,
-                body=[ast.Raise(lineno=expr.start_line,
-                                col_offset=expr.start_column)])]
+        # Likewise a bare (try) or (try BODY).
+        if not (handlers or finalbody):
+            raise HyTypeError(
+                expr,
+                "`try' must have an `except' or `finally' clause")
 
         ret = handler_results
 
@@ -838,6 +832,7 @@ class HyASTCompiler(object):
             value=body.force_expr,
             lineno=expr.start_line,
             col_offset=expr.start_column)
+
         body = body.stmts or [ast.Pass(lineno=expr.start_line,
                                        col_offset=expr.start_column)]
 

tests/compilers/test_ast.py

@@ -113,8 +113,6 @@ def test_ast_bad_raise():
 
 def test_ast_good_try():
     "Make sure AST can compile valid try"
-    can_compile("(try)")
-    can_compile("(try 1)")
     can_compile("(try 1 (except) (else 1))")
     can_compile("(try 1 (finally 1))")
     can_compile("(try 1 (except) (finally 1))")
@@ -125,8 +123,11 @@ def test_ast_good_try():
 
 def test_ast_bad_try():
     "Make sure AST can't compile invalid try"
+    cant_compile("(try)")
+    cant_compile("(try 1)")
     cant_compile("(try 1 bla)")
     cant_compile("(try 1 bla bla)")
+    cant_compile("(try (do bla bla))")
     cant_compile("(try (do) (else 1) (else 2))")
     cant_compile("(try 1 (else 1))")
     cant_compile("(try 1 (else 1) (except))")

tests/native_tests/language.hy

@@ -421,21 +421,10 @@
   "NATIVE: test do"
   (do))
 
-(defn test-bare-try [] (try
-    (try (raise ValueError))
-  (except [ValueError])
-  (else (assert False))))
-
 
 (defn test-exceptions []
   "NATIVE: test Exceptions"
 
-  (try)
-
-  (try (do))
-
-  (try (do))
-
   (try (do) (except))
 
   (try (do) (except [IOError]) (except))