* object.c (sym_to_proc): new method Symbol#to_proc; backported from 1.9. bug#19012

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@15987 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 29 insertions, 0 deletions

diff --git a/object.c b/object.c
index cd21f4efe6..c67381d5ec 100644
--- a/object.c
+++ b/object.c
@@ -1205,6 +1205,34 @@ sym_to_sym(sym)
     return sym;
 }
 
+static VALUE
+sym_call(args, mid)
+    VALUE args, mid;
+{
+    VALUE obj;
+
+    if (RARRAY_LEN(args) < 1) {
+	rb_raise(rb_eArgError, "no receiver given");
+    }
+    obj = rb_ary_shift(args);
+    return rb_apply(obj, (ID)mid, args);
+}
+
+/*
+ * call-seq:
+ *   sym.to_proc
+ *
+ * Returns a _Proc_ object which respond to the given method by _sym_.
+ *
+ *   (1..3).collect(&:to_s)  #=> ["1", "2", "3"]
+ */
+
+static VALUE
+sym_to_proc(VALUE sym)
+{
+    return rb_proc_new(sym_call, (VALUE)SYM2ID(sym));
+}
+
 
 /***********************************************************************
  *
@@ -2749,6 +2777,7 @@ Init_Object()
     rb_define_method(rb_cSymbol, "to_s", sym_to_s, 0);
     rb_define_method(rb_cSymbol, "id2name", sym_to_s, 0);
     rb_define_method(rb_cSymbol, "to_sym", sym_to_sym, 0);
+    rb_define_method(rb_cSymbol, "to_proc", sym_to_proc, 0);
     rb_define_method(rb_cSymbol, "===", rb_obj_equal, 1); 
 
     rb_define_method(rb_cModule, "freeze", rb_mod_freeze, 0);