$regsubex is a charm smile
sucky example:
Code:
alias hangman { 
  set %word carbon-oxide
  echo -a $regsubex(%word,/([a-z])/g,$+($chr(32),_,$chr(32)))
  ;simulate a guess for C
  set %word $replace(%word,c,C)
  echo -a $regsubex(%word,/([a-z])/g,$+($chr(32),_,$chr(32)))
  ;simulate a guess for O
  set %word $replace(%word,o,O)
  echo -a $regsubex(%word,/([a-z])/g,$+($chr(32),_,$chr(32)))
}