typed exception for returning outside of a routine

rakudo · May 15, 2012 · 38ea7c2 · 38ea7c2
1 parent 4687e02
commit 38ea7c2
Show file tree

Hide file tree

Showing 2 changed files with 23 additions and 4 deletions.
diff --git a/src/core/Exception.pm b/src/core/Exception.pm
@@ -608,6 +608,18 @@ my class X::Sequence::Deduction is Exception {
     method message() { 'Unable to deduce sequence' }
 }
 
+my class X::ControlFlow is Exception {
+    has $.illegal;   # something like 'next'
+    has $.enclosing; # ....  outside a loop
+
+    method message() { "$.illegal without $.enclosing" }
+}
+my class X::ControlFlow::Return is X::ControlFlow {
+    method illegal()   { 'return'  }
+    method enclosing() { 'Routine' }
+    method message()   { 'Attempt to return outside of any Routine' }
+}
+
 my class X::TypeCheck is Exception {
     has $.operation;
     has $.got;
@@ -630,12 +642,15 @@ my class X::TypeCheck::Return is X::TypeCheck {
 
 {
     my %c_ex;
-    %c_ex{'X::TypeCheck::Binding'} := sub ($got, $expected) {
+    %c_ex{'X::TypeCheck::Binding'} := sub ($got, $expected) is hidden_from_backtrace {
             X::TypeCheck::Binding.new(:$got, :$expected).throw;
         };
-    %c_ex{'X::TypeCheck::Return'} := sub ($got, $expected) {
+    %c_ex{'X::TypeCheck::Return'} := sub ($got, $expected) is hidden_from_backtrace {
             X::TypeCheck::Return.new(:$got, :$expected).throw;
         };
+    %c_ex{'X::ControlFlow::Return'} := sub () is hidden_from_backtrace {
+            X::ControlFlow::Return.new().throw;
+        };
     my Mu $parrot_c_ex := nqp::getattr(%c_ex, EnumMap, '$!storage');
     pir::set_hll_global__vsP('P6EX', $parrot_c_ex);
     0;

diff --git a/src/ops/perl6.ops b/src/ops/perl6.ops
@@ -1828,8 +1828,12 @@ inline op perl6_return_from_routine(in PMC) :flow {
         }
     }
     if (PMC_IS_NULL(cont)) {
-        Parrot_ex_throw_from_c_args(interp, NULL, EXCEPTION_INVALID_OPERATION,
-                "Attempt to return outside of any Routine");
+        PMC * const thrower = get_thrower(interp, "X::ControlFlow::Return");
+        if (PMC_IS_NULL(thrower))
+            Parrot_ex_throw_from_c_args(interp, NULL, EXCEPTION_INVALID_OPERATION,
+                    "Attempt to return outside of any Routine");
+        else
+            Parrot_pcc_invoke_sub_from_c_args(interp, thrower, "->");
     }
     ctx = CURRENT_CONTEXT(interp);
     GETATTR_Continuation_to_ctx(interp, cont, cctx);