Minimise imports #16

	on:
	pull_request:

	jobs:
	style_lint:
	name: Lint style
	runs-on: ubuntu-latest
	steps:
	# Check for long lines in .lean files and report if any lines exceed 100 characters
	- name: Check for long lines
	if: always()
	run: \|
	! (find Polya -name "*.lean" -type f -exec grep -E -H -n '^.{101,}$' {} \; \| grep -v -E 'https?://')

	- name: Don't 'import Mathlib', use precise imports
	if: always()
	run: \|
	! (find Polya -name "*.lean" -type f -print0 \| xargs -0 grep -E -n '^import Mathlib$')

	build_project:
	runs-on: ubuntu-latest
	name: Build project
	concurrency:
	group: ${{ github.workflow }}-${{ github.ref }}
	cancel-in-progress: true
	steps:
	- name: Checkout project
	uses: actions/checkout@v2
	with:
	fetch-depth: 0

	- name: Install elan
	run: curl https://raw.githubusercontent.com/leanprover/elan/master/elan-init.sh -sSf \| sh -s -- -y --default-toolchain leanprover/lean4:4.0.0

	- name: Get cache
	run: ~/.elan/bin/lake exe cache get \|\| true

	- name: Build project
	run: ~/.elan/bin/lake build Polya

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