Changing type of a variable from \Z to \N

Stream: new members

[Michael Wahlberg]

Is there a way to change the variable type inside a function from \Z to \N?

  if x < 0 then
    (x + b)
  else
    x

[Alex J. Best]

im not 100% sure what you are asking, but maybe tactic#lift

[Kyle Miller]

Maybe docs#int.to_nat would be helpful