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Hmm, I can't see maybe defined in Miranda's stdenv (cs.kent.ac.uk/people/staff/d), but it might have been a datatype commonly in use? That said, idiomatic Miranda and early Haskell leaned much more on partial functions, so it might have seen less use.

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Another Haskell precursor, Orwell, does not define it in its stdenv either: homepages.inf.ed.ac.uk/wadler/papers/

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You might need to go through the early Haskell papers and try to spot where it first appears 🤔

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Tom / Context Free

@contextfreeinfo

Thanks much for the digging you've done.

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As a fun aside, Mercury uses `yes` and `no` mercurylang.org/information/do 😂

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Interesting - I don't think I see a mention of Maybe in v1.0 of the Haskell Report? raw.githubusercontent.com/joyofhaskell/h … unless I'm missing something?

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Great moments in Haskell history

Going through typeclasses.com/timeline, it pops up in 1995 in web.cecs.pdx.edu/~mpj/pubs/spri - along with an Error type which looks very close to Rust's Result type! (unlike the Either type which was eventually added)

typeclasses.com

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Seems like Maybe and Either were then added to the Haskell report in version 1.3: raw.githubusercontent.com/joyofhaskell/h - so it seems like it is a Haskell thing?

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1:04 PM · Mar 19, 2022Twitter Web App

Would love to know more background on it, but it might require trawling through mailing lists, or emailing Mark P. Jones. Now I am curious about where and when Standard ML got option!

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Replying to

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See: smlfamily.github.io/Basis/option.h

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According to dl.acm.org/doi/10.1145/33, section 8.1, the original 1990 definition of Standard ML did not include an option type in its Basis library. This was added later by in Gansner and Reppy's specification of the basis library, but I'd imagine the idea would predate this?

dl.acm.org

The history of Standard ML | Proceedings of the ACM on Programming Languages

The ML family of strict functional languages, which includes F#, OCaml, and Standard ML, evolved from the Meta Language of the LCF theorem proving system developed by Robin Milner and his research...

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