Comparison with smart-pipelines proposal

[js-choi]

Hi, I’m the author of a smart pipelines proposal. It has already been formally specified, it has a Babylon plugin under development, and it will be presented to the TC39 by @littledan next week alongside the original pipelines proposal and an alternative pipeline proposal.

The smart pipelines proposal has a “topic style” that is very similar to your proposal. (N-ary expressions are deferred to an “additional feature”.)

Right now I’m hurrying to help prepare the presentation and the Babel plugin for TC39, so I don’t have free time to examine your proposal in detail right now. But I will definitely take a close look at it sometime. In the meantime, I would love to hear your response to the similarity between our proposals. 👍

[trustedtomato]

I rewrited some of your "topic style" examples using this proposal & the original pipeline proposal.

Your example...	...could be rewritten as
promise |> await # |> # || throw new TypeError( `Invalid value from ${#}`) |> doubleSay(#, ', ') |> capitalize(#) |> # + '!' |> new User.Message(#) |> await stream.write(#)	promise |> #await ? // diff1: the syntactic marker is needed |> #?0 || throw new TypeError( `Invalid value from ${?0}`) // diff2: 0 is needed in ?0 |> #doubleSay(?, ', ') |> capitalize // note1: there is no need to invoke the function |> #? + '!' |> #new User.Message(?) |> #await stream.write(?)
5 |> # - 3 |> -# |> # * 2 |> Math.max(#, 0)	5 |> #? - 3 |> #-? |> #? * 2 |> #Math.max(?, 0)

To remove those differences, some addition rules are needed.

Solution1

• to resolve diff1: The pipeline automatically creates an #… expression if the pipeline includes a ?.
• to resolve diff2: In this expression, all of the ?s point to the same argument.

Using these rules, my rewritten examples could be:

Your example...	...could be rewritten as
promise |> await # |> # || throw new TypeError( `Invalid value from ${#}`) |> doubleSay(#, ', ') |> capitalize(#) |> # + '!' |> new User.Message(#) |> await stream.write(#)	promise |> await ? |> ? || throw new TypeError( `Invalid value from ${?}`) |> doubleSay(?, ', ') |> capitalize |> ? + '!' |> new User.Message(?) |> await stream.write(?)
5 |> # - 3 |> -# |> # * 2 |> Math.max(#, 0)	5 |> ? - 3 |> -? |> ? * 2 |> Math.max(?, 0)

Problems

• I don't think its a good idea to remove the syntactic marker though due to the garden path problem.

Solution2

• to resolve diff2: recognize the |># pattern and point all of the ?s to the same argument.

Problems

• diff1 is not resolved.

Solution3

Same as Solution2, but the |> is interpreted as |>#.
This would resolve all differences.

Problems

• note1 would be "destroyed": 'hello' |> capitalize would be translated to 'hello' |> x => capitalize instead of 'hello |> x => capitalize(x)'.

Conclusion

Afterall, I don't think the original translations are too different, so keeping it as is would not be too bad.
But if you do, I think Solution3 is the most versatile one.
Let me know what you think!