unisonweb/unison

Add a Lisp-like syntax for Unison

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#1,842 opened on Mar 17, 2021

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Description

We eventually want to make the syntax for Unison pluggable. At the moment there's only one parser and pretty-printer, but in principle we can have as many syntaxes as we want. A good second syntax would be a Lisp-like one, since it should be particularly easy to implement.

The syntax of Clojure is particularly thoughtful and would be good to emulate since it's not just straight S-expressions.

E.g.

(ann mapReduce (Fn [loc -> (Fn [a -> b]) -> (Fn [b -> b -> b]) -> (List a) -> b]))
(defn mapReduce [loc fun ifEmpty reduce data]
  (match [(split data)]
    [Empty] ifEmpty
    [(One a)] (fun a)
    [(Two left right)]
      (let
        [fl (at loc '(mapReduce loc fun ifEmpty reduce !left))]
        [fr (at loc '(mapReduce loc fun ifEmpty reduce !right))]
        (reduce !fl !fr))

Contributor guide

Tech stack
None
Domain
developer experience
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
over 1 week
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
familiarity with Unison's ASTHaskell programmingunderstanding of parsers
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
25
Research direction
Investigate the current parser and pretty printer implementation in the Unison codebase. Study the Clojure syntax example provided in the issue. Explore how syntax pluggability might be designed, referencing the existing syntax structure. Check for any related issues or comments for additional context.