inverse of a function with some indexing

[justin2004]

should april throw a domain error like dyalog does or should it be able to handle this?

CL-USER> (april "{'ABC'[⍵]}2")
#\B
CL-USER> (april "({'ABC'[⍵]}⍣¯1)'B'")
NIL

      ({'ABC'[⍵]}⍣¯1)'B'
DOMAIN ERROR
      ({'ABC'[⍵]}⍣¯1)'B'
      ∧

[phantomics]

Interesting, it's a unique case for dfn inversion. You'll get a domain error when attempting to use ⌷⍣¯1 so perhaps that's what should happen in this case.

[phantomics]

This now returns an error, indexing is not possible in an inverted dfn.