wolfram-mathematica Evaluation Order Application of `ReplaceAll` and `ReplaceRepeated`

Example

Example of how ReplaceAll only applies a rule at most once, while ReplaceRepeated will do so in a loop but always restart application from the first rule.

x + a /. {
  a_ + z :> (Print[0]; DoneA),
   a_ + x :> (Print[1]; y + z), 
   a_ + y :> (Print[2]; DoneB)}

(* Prints "1", yields "y+z" *)

x + a //. {
  a_ + z :> (Print[0]; DoneA),
   a_ + x :> (Print[1]; y + z), 
   a_ + y :> (Print[2]; DoneB)}

(* Prints "1", then prints "0", yields "DoneA" *)