Fix lexical jump errors

lisp/kernel.gl

@@ -1,6 +1,6 @@
 ;; -*- mode: lisp-data -*-
 
-(prin1 (let ((l (block 'c (lambda () (return-from 'c 3)))))
+(prin1 (let ((l (block 'c (lambda () (return-from 'd 3)))))
          (block 'c
                 (funcall l))))
 (write-byte ?\n)

src/stack.c

@@ -419,9 +419,12 @@ DEFSPECIAL(return_from, "return-from", (LispVal * name, LispVal *value),
                 longjmp(*frame->block.target, 1);
             }
         }
+        // block went out of scope
+        lisp_signal(Qblock_out_of_scope_error, LIST(name));
+    } else {
+        // block never existed
+        lisp_signal(Qno_such_block_error, LIST(name));
     }
-    // block went out of scope
-    lisp_signal(Qno_such_block_error, LIST(name));
 }
 
 DEFUN(backtrace, "backtrace", (void), "()", "") {
@@ -442,5 +445,7 @@ DEFUN(backtrace, "backtrace", (void), "()", "") {
 
 DEFINE_SYMBOL(no_such_block_error, "no-such-block-error");
 DEFINE_CONDITION_CLASS(no_such_block_error, error);
+DEFINE_SYMBOL(block_out_of_scope_error, "block-out-of-scope-error");
+DEFINE_CONDITION_CLASS(block_out_of_scope_error, error);
 DEFINE_SYMBOL(excessive_lisp_nesting_error, "excessive-lisp-nesting-error");
 DEFINE_CONDITION_CLASS(excessive_lisp_nesting_error, error);

src/stack.h

@@ -157,6 +157,8 @@ DECLARE_FUNCTION(backtrace, (void) );
 
 DECLARE_SYMBOL(no_such_block_error);
 MAKE_CONDITION_CLASS(no_such_block_error);
+DECLARE_SYMBOL(block_out_of_scope_error);
+MAKE_CONDITION_CLASS(block_out_of_scope_error);
 DECLARE_SYMBOL(excessive_lisp_nesting_error);
 MAKE_CONDITION_CLASS(excessive_lisp_nesting_error);