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• Continuation Passing Style
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• Iterator Blocks Part Seven: Why no anonymous iterators?

  This annotation to a comment in part five I think deserves to be promoted to a post of its own. Why do we disallow anonymous iterators? I would love to have anonymous iterator blocks. I want to say something like: IEnumerable<int> twoints = ()=>{ Read More... Posted Monday, August 24, 2009 6:23 AM by Eric Lippert | 21 Comments Filed under: C#, Lambda Expressions, Language Design, Iterators

• Iterator Blocks, Part Six: Why no unsafe code?

  There are three good reasons to disallow unsafe blocks inside an iterator block. First, it is an incredibly unlikely scenario. The purpose of iterator blocks is to make it easy to write an iterator that walks over some abstract data type. This is highly Read More... Posted Monday, July 27, 2009 7:07 AM by Eric Lippert | 5 Comments Filed under: C#, Memory Management, Language Design, Iterators, unsafe code

• Iterator Blocks, Part Five: Push vs Pull

  A while back I posted some commentary I did for the Scripting Summer Games where I noted that there is an isomorphism between "pull" sequences and "push" events. Normally you think of events as something that "calls you", pushing the event arguments at Read More... Posted Thursday, July 23, 2009 7:05 AM by Eric Lippert | 13 Comments Filed under: C#, Language Design, Iterators, exception handling

• Iterator blocks Part Four: Why no yield in catch?

  Now that you know why we disallow yielding in a finally, it’s pretty straightforward to see why we also disallow yielding in a catch. First off, we still have the problem that it is illegal to “goto” into the middle of the handler of a try-protected region. Read More... Posted Monday, July 20, 2009 6:44 AM by Eric Lippert | 14 Comments Filed under: C#, Language Design, Iterators, exception handling

• Iterator Blocks, Part Three: Why no yield in finally?

  There are three scenarios in which code could be executing in a finally in an iterator block. In none of them is it a good idea to yield a value from inside the finally, so this is illegal across the board. The three scenarios are (1) normal cleanup, Read More... Posted Thursday, July 16, 2009 6:18 AM by Eric Lippert | 10 Comments Filed under: C#, Language Design, Iterators, exception handling

• Iterator Blocks, Part Two: Why no ref or out parameters?

  A long and detailed discussion of how exactly we implement iterator blocks would take me quite a while, and would duplicate work that has been done well by others already. I encourage you to start with Raymond’s series, which is a pretty gentle introduction: Read More... Posted Monday, July 13, 2009 6:35 AM by Eric Lippert | 7 Comments Filed under: C#, Memory Management, Language Design, Iterators

• Iterator Blocks, Part One

  There is a constant tension in language design between solving general problems and solving specific problems; finding the right spot on the general-to-specific spectrum can be quite tricky. The design of iterator blocks yields (ha ha) a germane example. Read More... Posted Thursday, July 09, 2009 7:11 AM by Eric Lippert | 8 Comments Filed under: C#, Continuation Passing Style, Language Design, Iterators