Vocabulary/lcapdot

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L. y Level Of

Rank Infinity -- operates on x and y as a whole -- WHY IS THIS IMPORTANT?



The greatest level of nesting of a boxed noun, or 0 if unboxed.

   L. 0$a:
0
   L. 1 2 3
0
   L. <,1
1
   L. (<,1),(<<,2)
2
   L. (<,1),(<<,2),(<<<,3)
3

Common Uses

Use boxopen to detect whether argument y is already boxed

boxopen=: <^:(L. = 0:)   NB. box y-arg if it is open or empty, but not otherwise

boxopen is a

  • Standard Library word(s) residing in the 'z'-locale.
  • Defined in the factory script stdlib.ijs.
  • View definition(s) by entering in the J session:  open'stdlib'


Related Primitives

Level At (u L: n), Spread (u S: n)