Ryan Williams ryan-williams

NE Scala 2020: "online-only" post-mortem

2020-03-20

On Saturday we wrapped up the Northeast Scala Symposium: a community-run conference related to the Scala programming language.

Going "online-only" at the last minute

On Tuesday, having sold 170 tickets to a conference starting Thursday at a venue in DUMBO, we decided to go "online only".

It's possible we should have made the call earlier. As is, some ppl were able to cancel their travel plans, others had already traveled, and (seemingly most) others had canceled on their own (or their employers had done it on their behalf).

Col1 is the field that will be the "rows" index
Col2 is the column whose values will become the new columns
Col3 is any other column (assuming that other columns are always filled; .count() will only count cells where Col3 has a value)

df \
.groupby(['Col1', 'Col2']) \
[['Col3']] \
.count() \
.reset_index() \
.pivot('Col1', 'Col2', 'Col3')

First, install pyenv:

curl https://pyenv.run | bash

(docs)

Follow its parting instructions to make sure you have pyenv in your $PATH:

# Load pyenv automatically by adding
# the following to ~/.bashrc:

Install libpcre2

In some situations, I've observed make below to fail for lack of a locatable libpcre2:

v=10.36
wget https://downloads.sourceforge.net/pcre/pcre2-$v.tar.bz2
tar -xvjf pcre2-$v.tar.bz2
pushd pcre2-$v
./configure --prefix="$HOME"
make
make install

wget https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/portable/openssh-8.0p1.tar.gz
tar -xvzf openssh-8.0p1.tar.gz
cd openssh-8.0p1
./configure --prefix=$HOME --with-privsep-path=$HOME/var/empty
make
make install

The --with-privsep-path=$HOME/var/empty is necessary to avoid an error like:

Run Kubeflow Pipelines on Minikube on macOS

Supplemental to Kubeflow Pipelines' docs about using Minikube.

Set up `minikube`

See Minikube docs.

Install `minikube`

The repro in shapeless#902 above is very simplified from my real use-case; perhaps I should just do something different upstream to avoid this, but nevertheless that behavior seems unexpected.

More context on my real use-case, fwiw:

A is actually OHList ("Options HList"), where each element in the underlying HList is wrapped in Option[_], and some relevant functionality is exposed.
TC is actually a comparator type-class Cmp, which defines logic for determining whether two instances of type T are equal:
- If they are not equal, it returns a customizable output-type Δ representing the computed diff.
```
trait Cmp[T] { type Δ; def apply(l: T, r: T): Option[Δ] }
```
In truth, [it is an alias](https://github.com/ryan-williams/test-utils/blob/lazy/cmp/shared/src/main/scala/org/hammer

	from os import chdir, getcwd
	from pathlib import Path


	class cd:
	"""Context manager for changing the current working directory"""
	def __init__(self, path):
	path = Path(path)
	self.path = path.expanduser()

	#!/usr/bin/env bash
	python3 gist_dir.py "$@"