* vm_eval.c (rb_f_caller): caller() method accepts second optional

  argument `n' which specify how many frames should return.
  For example, `caller(0, 1)' returns only one frame information
  which calls caller() method.  If there are less than n frame
  information, then all frame information are returned.  If n is 0,
  then always return [].
  This fix is part of [ruby-dev:42345] [Ruby 1.9-Feature#3917].
  However, performance and features are not enough.
  RDoc is also not available.
* test/ruby/test_backtrace.rb: add a test for above.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@35792 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 21 insertions, 9 deletions

diff --git a/vm_eval.c b/vm_eval.c
index cd83d42847..0160b66af6 100644
--- a/vm_eval.c
+++ b/vm_eval.c
@@ -1609,19 +1609,31 @@ rb_catch_obj(VALUE tag, VALUE (*func)(), VALUE data)
 static VALUE
 rb_f_caller(int argc, VALUE *argv)
 {
-    VALUE level;
-    int lev;
+    VALUE level, vn;
+    int lev, n;
 
-    rb_scan_args(argc, argv, "01", &level);
+    rb_scan_args(argc, argv, "02", &level, &vn);
 
-    if (NIL_P(level))
-	lev = 1;
-    else
-	lev = NUM2INT(level);
-    if (lev < 0)
+    lev = NIL_P(level) ? 1 : NUM2INT(level);
+
+    if (NIL_P(vn)) {
+	n = 0;
+    }
+    else {
+	n = NUM2INT(vn);
+	if (n == 0) {
+	    return rb_ary_new();
+	}
+    }
+
+    if (lev < 0) {
 	rb_raise(rb_eArgError, "negative level (%d)", lev);
+    }
+    if (n < 0) {
+	rb_raise(rb_eArgError, "negative n (%d)", n);
+    }
 
-    return vm_backtrace_str_ary(GET_THREAD(), lev+1, 0);
+    return vm_backtrace_str_ary(GET_THREAD(), lev+1, n);
 }
 
 void