[Jprogramming] Linking boxed strings with intervening spaces

[Ian Clark]

Suppose z is boxed strings, eg  z=: ;: 'alpha bravo charlie'

I half-recall there's a neater (single-primitive) way to recover the
string 'alpha bravo charlie' from z than:

   b2o=: [: }. [: ; ' ' ,&.> ]
   b2o z
alpha bravo charlie

but I've forgotten what it is and can't seem to find it in Voc or Dic.

On the page for "Raze" (;) the Dictionary says archly:
   The fit conjunction (;!.f) provides fill specified by the atom f
but AFAICS (;!.' ')z is the same as ;z , viz: 'alphabravocharlie' .

Nor incidentally is (;) listed as such on the page for "Fit" (!.) .

I observe however that:
   ;:inv z
alpha bravo charlie

But what's in my mind is a way of interleaving some other letter, or 2
spaces, or comma-space, etc.

BTW timer (6!:2) tells me that ;:inv is slower than b2o .