to starts.with? :sub :thing
  if empty? :sub [output "true]
  if empty? :thing [output "false]
  if not equal? first :sub first :thing [output "false]
  output starts.with? butfirst :sub butfirst :thing
end

to ends.with? :sub :thing
  if empty? :sub [output "true]
  if empty? :thing [output "false]
  if not equal? last :sub last :thing [output "false]
  output ends.with? butlast :sub butlast :thing
end

show starts.with? "dog "doghouse    ; true
show ends.with? "house "doghouse    ; true
show substring? "gho "doghouse       ; true  (built-in)