Running Oils as build shell

This document describes issues and notes on running Oils as Shell replacement in package building (either as /bin/bash or /bin/sh)

Nixpkgs

Oily Nixpkgs is an attempt at replacing bash with Oils in the stdenv.

Bugs/incompatibilities found with nixpkgs

• zulip, PR - "${a[@]+default}" doesn't properly expand as bash
• zulip, commit - ${mystr[@]} errors (e.g. it's a string) are often silent in bash
• zulip, commit - :& and ;;& in a case statement are missing in Oils
• zulip, commit - export x; x=(a b c) fails as only strings can be exported
• zulip - let is not implemented
  • Workaround (( EXPR )) | true
• zulip, [zulip thread](https://oilshell.zulipchat.com/#narrow/channel/307442-nix/topic/Assoc.20Array.20Quoting] - Oils requires quotes in certain assoc array expansions, e.g. ${myarr[a]-} needs to be ${myarr['a']} in Osh. See also blog post
  • nixpkgs patch underway
• [[ -v assoc[arr] ]] failed silently. Fixed but need to find link in zulip
• zulip, gh issue, certain [[ ... =~ ... ]] are a syntax err in Oils
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