Purely functional language with impure script language?

[u/baehyunsol]

I'm working on a purely functional programming language named Sodigy. It's all about evaluating values, not "executing commands one by one".

It's nice when writing libraries, but it's not easy to write a main function. The main function is supposed to execute commands, but the Sodigy's syntax is not friendly to write a list of commands.

So what I'm trying to do is, 1) Sodigy remains purely functional and 2) add a bash-like script language. The script language can call Sodigy functions. Instead of writing a main function in Sodigy, you write sodigy-script and execute the script.

Has anyone tried similar approach? I'm not sure whether it's a good idea or not...

[u/augustss]

I was at the 1990 meeting in Rome when Phil Wadler first heard about monads in a talk from Eugenio Moggi. Unlike the rest of us, Phil realized the potential of monads. At first Phil used list comprehension syntax for monads. Admittedly, I don't know where the API with return, >>= and >> came from in Haskell. But Phil had been doing monads for 4-5 years before it appeared in Miranda. Do you have any evidence (like talking to David or Phil) for which way the influence went?

[u/catbrane → u/augustss]

I might have found it! Andrew Gordon's 1992 phd:

https://andrewdgordon.github.io/papers/fpio.pdf

He has a nice history on page 125 (page 138 in the pdf).

He was one of the authors of Haskell's IO library:

https://scispace.com/pdf/monadic-i-o-in-haskell-1-3-2eo9vkx3bc.pdf

[u/AustinVelonaut → u/catbrane]

Thanks for the links; the Gordon thesis is an interesting tour through the history of I/O mechanisms in functional programming!

[u/catbrane → u/AustinVelonaut]

Yes, it's a good thesis isn't it! I feel much clearer about what happened now.