[Bug-apl] user defined functions using Unicode math chars

[Ala'a Mohammad]

Hi,

I'm trying to define user functions using some unicode characters, but
gnu-apl complains about the characters used not being from the defined
acceptable set:

√ ← {⍵ ⋆ ÷2}
Unknown APL character: √ (U+221A)
Non-APL character
      ∛  ← {⍵ ⋆ ÷3}

Unknown APL character: ∛ (U+221B)
Non-APL character

Is this a requirement by the standard?

Regards,

Ala'a