Ok this one took me some time. i never scripted a dash move before, and it was late and i was tired. However I managed to obtain something fundtionnal ^^

Come to think of it I didn't played a lot of games that features a dash, let alone took the time to really analyse the mechanic, so this whole new dash thing is a first to me.
I wished at first I could add a very short "wait" delay before it dashes, as if he was gathering energy to dash for a brief moment, but then I thought that a dash ought to be very responsive like an instant movement. Maybe at the end of the dash, there could be a small "rest" moment. Anyway I prefer moving forward.

At first I had some trouble because the dash would only trigger if the character was running in a way or in an other. At idle, it wouldn't trigger at all. That didn't felt natural, so I had to tinker a bit with my movement system so that the dash would actually override any walk move.
Also it's a forward dash, so I just had to multiply the dash speed by the direction the character is facing. This direction being 1 for right and -1 for left, it was perfect.
I used two timers, one for controlling the dash length, and another one as a short cooldown.

Then I added a maximum dash limit. Set to 1 for now, maybe it will be useful later on to power up the character a little to progressively allow for multiple dashes, allowing more complexity and difficulty to to trap dodging.