[glic3rinu]

By "state" I think OP is referring to an style of programming heavily based on global variables (global state). Function calls set global variables that the caller can read after. Functions and imports (sourcing) are all riddle with "side-effects", making the execution of the program very difficult to follow (spaghetti code).

Because "return values" in bash are implemented by echoing (printing to stdout):

  return=$(my_function arg1)

I believe OP has the point that echoing friendly-parsable output is a way of implementing "data-structures" in shells.

  result=$(my_function arg1)
  result_a=$(echo "$result" | grep A)
  result_b=$(echo "$result" | grep B)