Yep, that's fine - C# creates a new array on every params call. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dan Eloff Sent: Saturday, October 11, 2008 2:00 PM To: Discussion of IronPython Subject: Re: [IronPython] Why would you use MakeList over MakeListNoCopy?
On Sat, Oct 11, 2008 at 3:38 PM, Dino Viehland <[EMAIL PROTECTED]> wrote: > The difference is whether or not you're the owner of the array. If you've > accepted the array from some public location, even if it was a params method, > someone else could own the array and continue to modify it. If you've > created the array yourself or can guarantee it won't change then it can > safely be used for the underlying object array for the List object. That's what I figured about 5 minutes after I sent the email :( This stuff is burning my brain. One thing that is unclear to me, if you do l = MakeListNoCopy(x, y), is it legal to do l[0] = z ? It seems a little shaky to me, but if mutating a params array is legal in C#, then I suppose it shouldn't break. Thanks, -Dan > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dan Eloff > Sent: Saturday, October 11, 2008 1:29 PM > To: Discussion of IronPython > Subject: [IronPython] Why would you use MakeList over MakeListNoCopy? > > /// <summary> > /// Python runtime helper to create a populated instance of > Python List object. > /// </summary> > public static List MakeList(params object[] items) { > return new List(items); > } > > /// <summary> > /// Python runtime helper to create a populated instance of > Python List object w/o > /// copying the array contents. > /// </summary> > [NoSideEffects] > public static List MakeListNoCopy(params object[] items) { > return List.FromArrayNoCopy(items); > } > > If the second method "just works" then why would you ever want to use > MakeList? > > I seem to be creating a lot of 1 and 2 item lists here, so I'm looking > to make good use of one of these guys. (I really miss C# 3.0 > collection initializers) > > Work on porting _ast is going well, so far I've had no insurmountable > obstacles. I expect to be done it by Monday. The AST produced is close > (but not identical) to CPython, but that shouldn't matter. Each node > has the same properties with the exact same types so walking the tree > should work equally on both platforms. > > Thanks, > -Dan > _______________________________________________ > Users mailing list > Users@lists.ironpython.com > http://lists.ironpython.com/listinfo.cgi/users-ironpython.com > _______________________________________________ > Users mailing list > Users@lists.ironpython.com > http://lists.ironpython.com/listinfo.cgi/users-ironpython.com > _______________________________________________ Users mailing list Users@lists.ironpython.com http://lists.ironpython.com/listinfo.cgi/users-ironpython.com _______________________________________________ Users mailing list Users@lists.ironpython.com http://lists.ironpython.com/listinfo.cgi/users-ironpython.com
