Re: How do you implement a recursive walker of a tree with a lazy range?

Chris Cain: InputRange!Tree walk() { return inputRangeObject(chain( [this], children.map!(a=a.walk())().joiner())); } I have used your nice idea to create another partial D solution for this task: http://rosettacode.org/wiki/Tree_traversal#D

Re: How do you implement a recursive walker of a tree with a lazy range?

On 10/30/13, Chris Cain clc...@uncg.edu wrote: I'm not confident that this is the most efficient way, but it works. It allocates, I'm looking for a lazy range. I would be surprised that such a common task as iterating a tree is not possible without using classes and workarounds.

Re: How do you implement a recursive walker of a tree with a lazy range?

Am 30.10.2013 15:58, schrieb Andrej Mitrovic: On 10/30/13, Chris Cain clc...@uncg.edu wrote: I'm not confident that this is the most efficient way, but it works. It allocates, I'm looking for a lazy range. I would be surprised that such a common task as iterating a tree is not possible

Re: How do you implement a recursive walker of a tree with a lazy range?

On Wednesday, 30 October 2013 at 14:58:21 UTC, Andrej Mitrovic wrote: It allocates, I'm looking for a lazy range. I would be surprised that such a common task as iterating a tree is not possible without using classes and workarounds. It allocates, but it's still a lazy range. It only

Re: How do you implement a recursive walker of a tree with a lazy range?

On Wednesday, 30 October 2013 at 12:55:41 UTC, bearophile wrote: I have used your nice idea to create another partial D solution for this task: http://rosettacode.org/wiki/Tree_traversal#D ... snip ... Very cool! It's pretty close to being done. I'd have to give some real thought to how a

Re: How do you implement a recursive walker of a tree with a lazy range?

On Wednesday, 30 October 2013 at 16:50:33 UTC, Chris Cain wrote: you would avoid allocations. Actually, let me clarify. You'd avoid *those* allocations. inputRangeObject allocates a class. Unfortunately, I'm not certain it's possible to do this cleanly without such a thing using

Re: How do you implement a recursive walker of a tree with a lazy range?

On Wed, Oct 30, 2013 at 1:55 PM, bearophile bearophileh...@lycos.comwrote: alias VisitRange(T) = InputRange!(const Tree!T); Does that syntax come with DMD 2.064? The (T) part, I mean.

Re: How do you implement a recursive walker of a tree with a lazy range?

On Wednesday, 30 October 2013 at 17:31:10 UTC, Philippe Sigaud wrote: On Wed, Oct 30, 2013 at 1:55 PM, bearophile bearophileh...@lycos.comwrote: alias VisitRange(T) = InputRange!(const Tree!T); Does that syntax come with DMD 2.064? The (T) part, I mean. Yes.

Re: How do you implement a recursive walker of a tree with a lazy range?

On 10/30/13, Philippe Sigaud philippe.sig...@gmail.com wrote: Does that syntax come with DMD 2.064? The (T) part, I mean. Yes. Glad to see you here btw, do you have your own solution to the problem?

Re: How do you implement a recursive walker of a tree with a lazy range?

On Wed, Oct 30, 2013 at 7:09 PM, Andrej Mitrovic andrej.mitrov...@gmail.com wrote: On 10/30/13, Philippe Sigaud philippe.sig...@gmail.com wrote: Does that syntax come with DMD 2.064? The (T) part, I mean. Yes. Ah, that's cool! I've been waiting for that one for years. Glad to see you

How do you implement a recursive walker of a tree with a lazy range?

Instead of the usual opApply approach, how would you implement an auto return walker function *without* defining a special external struct that holds all the logic? In other words, using existing Phobos functionality only, composing functions like map and chain. Example code which isn't correct:

Re: How do you implement a recursive walker of a tree with a lazy range?

Here's the code: InputRange!Tree walk() { return inputRangeObject(chain( [this], children.map!(a=a.walk())().joiner())); } Result: --- [root, root.1, root.1.1, root.1.2, root.2, root.2.1, root.2.2] --- It's a bit confusing to explain how I