[Jprogramming] singletons with |. and |:

[Dan Bron]

I think you've just got a typo.  The first few lines of each block of your message uses a conjunction and the last uses a verb.

>    !. a
>    |. ''  NB. Ok

>    !: a
>    |: ''  NB. ok

I think you meant to type:

	   a =. 'a'   
	   |. 'a'
	a
	   |. a
	a
	   |: 'a'
	a
	   |: a
	a

Unless I misunderstood why you're comparing  !.  Vs  |.  and  !:  vs  |:  . 

-Dan