<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On Mar 30, 2011, at 2:51 PM, Tristan Seligmann wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>On Wed, Mar 30, 2011 at 7:20 PM, Glyph Lefkowitz<br><<a href="mailto:glyph@twistedmatrix.com">glyph@twistedmatrix.com</a>> wrote:<br><blockquote type="cite">However, in my experience, a novice's understanding of addCallbacks() is<br></blockquote><blockquote type="cite">critically important to understanding other uses of Deferred as well; in<br></blockquote><blockquote type="cite">particular, the "one chain of pairs of callback and errback" concept makes a<br></blockquote><blockquote type="cite">lot of the behavior clear which might not otherwise be. If you just vaguely<br></blockquote><blockquote type="cite">know about chains of callbacks, you can easily get confused.<br></blockquote><br>Anecdotally, I didn't understand Deferred callback chains at all<br>correctly until I discovered that addCallback and addErrback were<br>implemented in terms of addCallbacks, and how they were implemented.<br></div></blockquote><br></div><div>Great, so, my evidence-free claim and another your personal anecdotal experience agree; I believe this gives us what Science calls a "law", and thus the topic bears no further discussion :).</div><div><br></div><div>Seriously though, this is pretty much exactly what I meant. You don't need to call addCallbacks a lot, but (A) sometimes you do and when you do need it it's important, and (B) it's important for people to <i>understand</i> early in the process even if they're not going to use it a lot.</div></body></html>