Stair-climbing puzzle: Difference between revisions

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 '''Solution (Tacit):'''
 <lang j>step         =: 0.6 > ?@0:
-attemptClimb =: [: <:`>:@.step #@(''"_)
+attemptClimb =: [: <:`>:@.step 0:
 isNotUpOne   =: -.@(+/@])
-step_up=: (] , attemptClimb)^:isNotUpOne^:_     NB. no variables or numbers</lang>
+step_up=: (] , attemptClimb)^:isNotUpOne^:_</lang>
-Note that J's verbs (functions) must always take an argument i.e. there is no such thing as a niladic verb. Verbs that ignore their arguments (e.g. <code>step</code>) achieve the same effect.
+Note that <code>0:</code> is not a number but a verb (function) that returns the number zero irrespective of its argument(s). Therefore the above solution for <code>step_up</code> meets the restrictions of no variables or numbers.
+J's verbs (functions) always take an argument i.e. there is no such thing as a niladic verb. Verbs that ignore their arguments (e.g. <code>step</code> and <code>attemptClimb</code>) achieve the same effect.
 '''Solution (Explicit):'''