feat: add 'directly head/tail recursion' optimized syntax '+' #211

	#
	# american fuzzy lop++ - grammar mutator
	# --------------------------------------
	#
	# Written by Shengtuo Hu
	#
	# Copyright 2020 AFLplusplus Project. All rights reserved.
	#
	# Licensed under the Apache License, Version 2.0 (the "License");
	# you may not use this file except in compliance with the License.
	# You may obtain a copy of the License at:
	#
	# http://www.apache.org/licenses/LICENSE-2.0
	#
	# A grammar-based custom mutator written for GSoC '20.
	#

	name: Grammar Mutator CI

	on: [push, pull_request]

	jobs:
	cmake-build:
	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v2
	- name: Install dependencies
	run: \|
	bash .github/workflows/setup-deps.sh
	- name: Create build directory
	run: \|
	mkdir build
	- name: CMake
	run: \|
	cd ./build
	cmake -DENABLE_TESTING=ON -DANTLR_JAR_LOCATION=$(realpath ../antlr-4.8-complete.jar) -DGRAMMAR_FILE=$(realpath ../grammars/ruby.json) ../
	- name: Compile
	run: cmake --build build --parallel $(nproc)
	- name: Unit testing
	run: \|
	cd ./build
	make test
	- name: Valgrind memcheck on unit testing
	run: \|
	cd ./build
	make test_memcheck

	make-build:
	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v2
	- name: Install dependencies
	run: \|
	bash .github/workflows/setup-deps.sh
	- name: Compile
	run: \|
	make -f GNUmakefile ENABLE_TESTING=1 GRAMMAR_FILE=grammars/ruby.json ANTLR_JAR_LOCATION=./antlr-4.8-complete.jar -j$(nproc)
	- name: Unit testing
	run: \|
	make -f GNUmakefile test
	- name: Valgrind memcheck on unit testing
	run: \|
	make -f GNUmakefile test_memcheck

Provide feedback