Rustom Mody
As for APL, it failed for various reasons eg - mixing up assembly language (straight line code with gotos) with functional idioms - the character set was a major hurdle in the 60s. Thats not an issue today when most OSes/editors are unicode compliant
I know it's bikeshedding, but I think Agda and Idris are more relevant to Haskell than APL, since their semantics are closer (and they're both implemented in Haskell). Agda makes extensive (ab)use of Unicode identifiers, eg. https://github.com/agda/agda-stdlib/blob/master/src/Algebra.agda Idris specifically avoids Unicode identifiers, for reasons outlined at https://github.com/idris-lang/Idris-dev/wiki/Unofficial-FAQ Personally I prefer working in Idris to Agda, since the Unicode puts me off. I usually resort to copy/pasting symbols, which is tedious compared to typing names. Cheers, Chris