[Maxima-discuss] is(equal(op(f(x,y)), 'del)) -> unknown

[Eduardo O. <edu...@gm...>]

Hi list,

if I run these expressions in the REPL

  is(equal(op(del(w)), 'del));
  is(equal(op(f(x,y)), 'del));
  if is(equal(op(del(w)), 'del)) then "yes" else "no";
  if is(equal(op(f(x,y)), 'del)) then "yes" else "no";

I get this:

  (%i1) is(equal(op(del(w)), 'del));
  (%o1)                                true
  (%i2) is(equal(op(f(x,y)), 'del));
  (%o2)                               unknown
  (%i3) if is(equal(op(del(w)), 'del)) then "yes" else "no";
  (%o3)                                 yes
  (%i4) if is(equal(op(f(x,y)), 'del)) then "yes" else "no";
  (%o4)                     if unknown then yes else no
  (%i5)

The is(equal(op(o),'del)) returns "true", "false", or "unknown". How
do I replace it by something that converts the "unknown"s to "false"s?

  Thanks in advance!
    Eduardo Ochs
    http://anggtwu.net/eev-maxima.html