Exploring and visualising Scala 2.* compilation phases

HelloWorld.scala

object HelloWorld extends App {
	val add2: Int => Int = _ + 2

	println(s"Hello world! This is Scala. ${add2(40)}")
}

phases.sh

#!/usr/bin/env bash
set -e

# Author: Oto Brglez, @otobrglez
# Usage: ./phases.sh What.scala
# Generates final.gif

# Cleanup from previous runs
rm -rf *.scala.html *.scala.pdf *.gif

vimhtml() { [[ -f "$1" ]] || return 1; vim +'syn on | run! syntax/2html.vim | wq | q' "$1";}

SCALAC_FLAGS="-Dfile.encoding=UTF-8"

# Get all phases that scalac compiler has
PHASES=($(scalac -Xshow-phases | tail -n +3 | tr -d ' ' | awk -F '[0-9]+' '{print $1}' | tr '\n' ' '))

# Loop over phases and do magic
for i in "${!PHASES[@]}"; do 
  fi=$(printf "%02d\n" $i)
  phase=${PHASES[$i]}
  output=${fi}-${phase}-$1
  
  echo "Phase: ${phase} - ${fi}"
  scalac -Xprint:${phase} ${SCALAC_FLAGS} $1 2>&1 | tee ${output}
  
  # Scala to HTML
  vimhtml ${output}

  # HTML to PDF
  wkhtmltopdf --disable-smart-shrinking --zoom 1.2 --page-size A4 ${output}.html ${output}.pdf
done

# Convert PDFs to GIF
echo "Converting PDFs to GIF"
convert -verbose -delay 150 -density 150 \
  -page a4  "*.scala.pdf[0]" final.gif

What.scala

// A trivial example; asked by @Krever01 on https://twitter.com/Krever01/status/1419568385134845953
object What extends App {
	
	val y = 2
	var x = 40 

	x += y

	println(x)
}