I'd like to post results of my small experiment to evaluate how awesome the reuse of binaries between snapshots is. 

I did the following:

1. Clean the C:\Users\<username>\AppData\Roaming\stack
2. Build my project for LTS-3.3
- 6 minutes
3. Switch to LTS-3.4 and build
- 20 seconds!

The reason? Here it is:

cmdargs-0.10.13: copying precompiled package
dlist-0.7.1.2: copying precompiled package
executable-path-0.0.3: copying precompiled package
nats-1: copying precompiled package
mtl-2.2.1: copying precompiled package
network-2.6.2.1: copying precompiled package
old-locale-1.0.0.7: copying precompiled package
base-orphans-0.4.4: copying precompiled package
parallel-3.2.0.6: copying precompiled package
prelude-extras-0.4: copying precompiled package
primitive-0.6: copying precompiled package
reflection-2: copying precompiled package
mtl-compat-0.2.1.3: copying precompiled package
split-0.2.2: copying precompiled package
old-time-1.1.0.3: copying precompiled package
stm-2.4.4: copying precompiled package
syb-0.5.1: copying precompiled package
tagged-0.8.1: copying precompiled package
text-1.2.1.3: copying precompiled package
transformers-compat-0.4.0.4: copying precompiled package
utf8-string-1.0.1.1: copying precompiled package
vector-0.10.12.3: copying precompiled package
StateVar-1.1.0.1: copying precompiled package
blaze-builder-0.4.0.1: copying precompiled package
hashable-1.2.3.3: copying precompiled package
parsec-3.1.9: copying precompiled package
distributive-0.4.4: copying precompiled package
exceptions-0.8.0.2: copying precompiled package
string-conversions-0.4: copying precompiled package
blaze-textual-0.2.1.0: copying precompiled package
unordered-containers-0.2.5.1: copying precompiled package
scientific-0.3.3.8: copying precompiled package
network-uri-2.6.0.3: copying precompiled package
semigroups-0.16.2.2: copying precompiled package
json-builder-0.3: copying precompiled package
attoparsec-0.12.1.6: copying precompiled package
HTTP-4000.2.20: copying precompiled package
bifunctors-5: copying precompiled package
void-0.7: copying precompiled package
aeson-0.8.0.2: copying precompiled package
contravariant-1.3.2: copying precompiled package
comonad-4.2.7.2: copying precompiled package
profunctors-5.1.1: copying precompiled package
semigroupoids-5.0.0.4: copying precompiled package
free-4.12.1: copying precompiled package
adjunctions-4.2.1: copying precompiled package
kan-extensions-4.2.2: copying precompiled package
lens-4.12.3: copying precompiled package
lens-aeson-1.0.0.4: copying precompiled package

Not a single of my dependencies was actually rebuilt! How awesome is that!

Thanks,
Michał 

On Fri, Sep 4, 2015 at 1:41 PM, Michal Antkiewicz <mantkiew@gsd.uwaterloo.ca> wrote:
what a great release! Esp. the reuse of binaries between snapshots!

  • Support added for compiling with GHCJS
I presume that stack does not assist in installing GHCJS itself as it does for ghc. Are there any plans of improving the ghcjs situation? What are the current blockers?

Thanks,
Michal