Compiled regular expression is

(?-xism:(?{\%unambiguities})^(ali(?:a(?:s)?)?|all(?:o(?:w)?)?|appe(?:a(?:r)?)?|appl(?:y)?|b(?:e(?:g(?:i(?:n)?)?)?)?|clean|clear|clon(?:e)?|clos(?:e)?|co(?:m(?:p(?:a(?:r(?:e)?)?)?)?)?)$(?{$$rsChoice = $^R->{$1}}))

Choose from following, partial unambiguous entry OK
   alias allow appear apply begin clean clear clone close compare
Please choose (or Ctrl-D to exit) ? a
"a" is ambiguous, could be any one of - alias allow appear apply

Choose from following, partial unambiguous entry OK
   alias allow appear apply begin clean clear clone close compare
Please choose (or Ctrl-D to exit) ? al
"al" is ambiguous, could be any one of - alias allow

Choose from following, partial unambiguous entry OK
   alias allow appear apply begin clean clear clone close compare
Please choose (or Ctrl-D to exit) ? ali
You chose: alias

Choose from following, partial unambiguous entry OK
   alias allow appear apply begin clean clear clone close compare
Please choose (or Ctrl-D to exit) ? b
You chose: begin

Choose from following, partial unambiguous entry OK
   alias allow appear apply begin clean clear clone close compare
Please choose (or Ctrl-D to exit) ? d
"d" not recognised

Choose from following, partial unambiguous entry OK
   alias allow appear apply begin clean clear clone close compare
Please choose (or Ctrl-D to exit) ? ^D