Problem Statement

An animation with the following frames in the following order (if certain characters aren't available or can't be used correctly in the programming language, alternate characters can replace any of these frames) must animate with a delay of 0.25 seconds between each frame, with the previous frame being cleared before the next frame appears:

A stand-alone version that loops and/or a version that doesn't loop can be made. These examples can also be converted into a system used in game development which is called on a HUD or GUI element requiring it to be called each frame to output the text, and advance the frame when the frame delay has passed. You can also use alternate text such as the . animation ( . | .. | ... | .. | repeat from . ) or the logic can be updated to include a ping/pong style where the frames advance forward, reach the end and then play backwards and when they reach the beginning they start over ( technically, you'd stop one frame prior to prevent the first frame playing twice, or write it another way ).

There are many different ways you can incorporate text animations. Here are a few text ideas - each frame is in quotes. If you can think of any, add them to this page! There are 2 examples for several of these; the first is the base animation with only unique sets of characters. The second consists of the primary set from a - n and doubled, minus the first and last element ie: We only want the center. This way an animation can play forwards, and then in reverse ( ping ponging ) without having to code that feature. For the animations with 3 elements, we only add 1, the center. with 4, it becomes 6. with 10, it becomes 18.

We don't need the second option for some of the animations if they connect smoothly, when animated, back to the first element. ... doesn't connect with . cleanly - there is a large leap. The rotating pipe meets the first perfectly so it isn't necessary, etc..

Let's start with the solution:

: rod
  cr
  begin
            [char] \ emit 250 ms
    13 emit [char] | emit 250 ms
    13 emit [char] - emit 250 ms
    13 emit [char] / emit 250 ms
    13 emit
    key?
  until
;
rod


include lib/yield.4th

: spin 8 emit emit sync ;              ( c --)

: spinner                              ( --)
  begin
    [char] | spin yield [char] / spin yield 
    [char] - spin yield [char] \ spin yield
  again
;
                                       ( n -- n+1 f)
: payload 10000000 0 do loop dup 1+ swap 100 < ;
                                       \ dummy task
: test
  ." Wait for it.. " spinner 0         \ start coroutine
  begin payload while yield repeat     \ show spinner while doing it
  drop grab bl spin cr                 \ grab control, finish spinner
  ." Done!" cr                         \ all done
;

test