Has operator

Has operator checks if an argument has a given method declared. There is the callback method ``_has(methodName)´´ for classes. If the expression is given on the right side, it is evaluated to string.

If ``has´´ is followed by ``!´´ then the meaning of expression is negated. Read as "x has NOT y".

  has-expr := expr "has" ["!"] symbolname 
  has-expr := expr "has" ["!"] "(" expr ")" 

Add a note