* array.c (rb_ary_s_try_convert): a new class method to convert

  object or nil if it's not target-type.  this mechanism is used
  to convert types in the C implemented methods.

* hash.c (rb_hash_s_try_convert): ditto.

* io.c (rb_io_s_try_convert): ditto.

* re.c (rb_reg_s_try_convert): ditto.

* string.c (rb_str_s_try_convert): ditto.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@13251 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 17 insertions, 0 deletions

diff --git a/re.c b/re.c
index 608e43dda9..6f2f3c0e23 100644
--- a/re.c
+++ b/re.c
@@ -2034,6 +2034,22 @@ rb_check_regexp_type(VALUE re)
     return rb_check_convert_type(re, T_REGEXP, "Regexp", "to_regexp");
 }
 
+/*
+ *  call-seq:
+ *     Regexp.try_convert(obj) -> re or nil
+ *
+ *  Try to convert <i>obj</i> into a Regexp, using to_regexp method.
+ *  Returns converted regexp or nil if <i>obj</i> cannot be converted
+ *  for any reason.
+ *
+ *     IO.try_convert(/re/)      # => /re/
+ *     IO.try_convert("re")      # => nil
+ */
+static VALUE
+rb_reg_s_try_convert(VALUE dummy, VALUE re)
+{
+    return rb_check_regexp_type(re);
+}
 
 /*
  *  call-seq:
@@ -2422,6 +2438,7 @@ Init_Regexp(void)
     rb_define_singleton_method(rb_cRegexp, "escape", rb_reg_s_quote, -1);
     rb_define_singleton_method(rb_cRegexp, "union", rb_reg_s_union, -1);
     rb_define_singleton_method(rb_cRegexp, "last_match", rb_reg_s_last_match, -1);
+    rb_define_singleton_method(rb_cRegexp, "try_convert", rb_reg_s_try_convert, 1);
 
     rb_define_method(rb_cRegexp, "initialize", rb_reg_initialize_m, -1);
     rb_define_method(rb_cRegexp, "initialize_copy", rb_reg_init_copy, 1);