As Felix says, a promise is just another value to be yielded. However, there is a style of writing asynchronous code which makes use of yielded promises in a particular way. This involves a surrounding piece of code which invokes the generator, then waits for the yielded promise to resolve, and then and only then … Read more
You could use rest parameters … and check the length of the rest array for another calling of the generator function* flat(a, …r) { if (Array.isArray(a)) { yield* flat(…a); } else { yield ‘foo’ + a; } if (r.length) { yield* flat(…r); } } var obj = [1, 2, 3, [4, 5, [6, 7, 8], … Read more
You can’t pass multiple blocks, per se, but you can pass multiple procs or lambdas: Using 1.9 syntax: opportunity ->{ @some_array.empty? }, ->{ @some_other_array.empty? } and in the method itself: def opportunity(lambda1, lambda2) if lambda1.() @opportunities += 1 end if lambda2.() @performances += 1 end end
Ruby’s yield is not an iterator like in C# and Python. yield itself is actually a really simple concept once you understand how blocks work in Ruby. Yes, blocks are a functional programming feature, even though Ruby is not properly a functional language. In fact, Ruby uses the method lambda to create block objects, which … Read more
I think the first one is actually a syntactic sugar of the other. In other words there is no behavioural difference. What the second form allows though is to “save” the block in a variable. Then the block can be called at some other point in time – callback. Ok. This time I went and … Read more
This is happening because resources caching is enabled on the Server. Three possible solutions I know about: 1.Disable resources caching on the server. Instructions are different for every web server. Usually done in .htaccess. 2.Make each request with unique timestamp. The time should in Unix format. This method will not work on iOS. You are … Read more
tl;dr <update>: As of Python 3.5 (currently in beta) just use os.scandir </update> As I’ve written earlier, since “iglob” is just a facade for a real iterator, you will have to call low level system functions in order to get one at a time like you want. Fortunately, calling low level functions is doable from … Read more
Summarizing the comments: you can’t use yield inside a regular function, so you can’t use yield with forEach. Here an example of “generatorized” foreach: function * foreach (arr, fn) { var i for (i = 0; i < arr.length; i++) { yield * fn(arr[i]) } } function * gen (number) { yield number + 1 … Read more
It’s feasible but it is a bad idea. Iterator blocks were created to help you write custom iterators for collections, not for solving the general-purpose problem of implementing state machines. If you want to write a state machine, just write a state machine. It’s not hard. If you want to write a lot of state … Read more
Eric Lippert recently wrote a series of blog posts about why yield is not allowed in some cases. Part 1 Part 2 Part 3 Part 4 Part 5 Part 6 EDIT2: Part 7 (this one was posted later and specifically addresses this question) You will probably find the answer there… EDIT1: this is explained in … Read more