Readme #42

	name: Readme

	on:
	# Run once a month, to detect unexpected regressions
	schedule:
	- cron: '0 0 1 * *'

	# To test this GitHub Action, uncomment this block and open a PR; then comment
	# it out again before merging the PR.
	#pull_request:
	# types: [opened, synchronize]

	jobs:
	readme:
	name: Run code from README.md
	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v2

	- uses: actions/cache@v2
	name: Cache Stack Artifacts
	with:
	path: \|
	~/.stack
	.stack-work
	key: ${{ runner.os }}-stack-${{ hashFiles('stack-8.10.7.yaml') }}

	- uses: haskell/actions/setup@v1
	id: setup-haskell-stack
	name: Setup Stack
	with:
	enable-stack: true
	stack-setup-ghc: true
	stack-no-global: true

	- name: Extract and run code
	run: \|
	TEST_FILE="TEST_Readme.hs"
	README="$(cat README.md)"
	CODE="$(echo "$README" \| grep '^ ' \| sed 's/^ //g')"

	echo "module T where" > "$TEST_FILE"
	echo "$CODE" >> "$TEST_FILE"

	# {-# LANGUAGE LambdaCase, ScopedTypeVariables #-}
	EXTS_LINE="$(echo "$CODE" \| head -n 1)"

	# LambdaCase
	# ScopedTypeVariables
	EXTS="$(echo "$EXTS_LINE" \| tr ' ' '\n' \| grep -v '#' \| grep -v "LANGUAGE" \| tr -d ',')"

	# -XLambdaCase
	# -XScopedTypeVariables
	DOCTEST_FLAGS="$(echo "$EXTS" \| sed 's/^/-X/g')"


	stack --stack-yaml="stack-8.10.7.yaml" install doctest
	stack exec -- doctest $DOCTEST_FLAGS $TEST_FILE

Provide feedback