[isabelle-dev] Update of Haskell Stack

[Makarius]

Here are some notable changes concerning the Haskell Stack, which is a
build tool with a package repository behind it:

changeset:   69526:5574d504cf36
tag:         tip
user:        wenzelm
date:        Fri Dec 28 19:01:35 2018 +0100
files:       etc/settings
description:
more conservative update of Haskell stack (amending 04e54f57a869): 13.0
still lacks notable packages like "Agda" or "darcs";


changeset:   69512:04e54f57a869
parent:      69506:7d59af98af29
user:        Lars Hupel <lars.hupel at mytum.de>
date:        Thu Dec 27 17:36:19 2018 +0100
files:       etc/settings src/Pure/General/path.ML
description:
update LTS Haskell version


I am myself still in the process of learning how the Stack community and
release process works. Spending 5 min with the announcement of lts-13.0
from Isabelle/04e54f57a869 leaves the impression that a new major
release is merely the factual start for package maintainers to become
serious about updating and publishing their stuff.

Haskell Stack LTS versions should appear every 3-6 months -- according
to the official statement
https://github.com/commercialhaskell/lts-haskell#readme

So it looks like it is better to stay one major release version behind
the frontier of ongoing LTS development. Moreover, I have so far
refrained from updating minor versions without particular reasons: it
always causes a lot of network traffic and disk usage increase for local
.stack directories.


Here is also a concrete project that refers to Isabelle/Haskell from
isabelle-dev and is in sync with its Stack version:


https://github.com/Naproche/Naproche-SAD/commit/2af938e09a61c14f57af40679bb340a92b521331

This proves the use and usability of the emerging Isabelle/Haskell
infrastructure. In the longer term it might help more users out there to
develop Haskell-based projects for Isabelle; or just use other ITP
systems like Agda -- when OPAM gets into better shape we could also
apply this principle to Coq.


Overall, the general approach of the Isabelle distribution is to deliver
canonical versions of add-on tools that just work without manual tinkering.

Thus "latest" things require more than one close look before adopting them.


	Makarius