Compiler selector for macOS

compiler.sh

compiler() {
	# After installing compilers in macOS:
	#   brew install gcc gcc@4.9 gcc@5 gcc@6 llvm@3.9 llvm@4 llvm@5
	# Use compiler <compiler> to select it. Ex.:
	#   compiler llvm@5

	compiler=$1

	if [ -z "$compiler" ]; then
		if [ -z "$COMPILER" ]; then
			echo "* default"
			ls -1 "/usr/local/opt/" | grep -E "gcc|llvm" | sed -e "s#^#  #"
		else
			echo "  default"
			ls -1 "/usr/local/opt/" | grep -E "gcc|llvm" | sed -e "s#^#  #" | sed -e "s#  $COMPILER\$#* $COMPILER#"
		fi
		return 1
	fi

	case $1 in
		gcc*)
			if [ -d "/usr/local/opt/$compiler" ]; then
				export COMPILER=$compiler
				export COMPILER_PATH="/usr/local/opt/$compiler"
				export PATH="$COMPILER_PATH/bin:$(echo "$PATH" | sed -e 's#:/usr/local/opt/[^/]*/bin##')"
				export CC="$(ls $COMPILER_PATH/bin/gcc* | head -1)"
				export CXX="$(ls $COMPILER_PATH/bin/g++* | head -1)"
				export CPP="$(ls $COMPILER_PATH/bin/cpp* | head -1)"
				export AR="$(ls $COMPILER_PATH/bin/gcc-ar* | head -1)"
				export NM="$(ls $COMPILER_PATH/bin/gcc-nm* | head -1)"
				export RANLIB="$(ls $COMPILER_PATH/bin/gcc-ranlib* | head -1)"
				export CFLAGS="-I$COMPILER_PATH/include"
				export CXXFLAGS="-I$COMPILER_PATH/include"
				export CPPFLAGS="-I$COMPILER_PATH/include"
				export LDFLAGS="-L$COMPILER_PATH/lib -Wl,-rpath,/usr/local/opt/$compiler/lib"
				unset ASAN_SYMBOLIZER_PATH
				unset MSAN_SYMBOLIZER_PATH
				unset TSAN_SYMBOLIZER_PATH
				unset UBSAN_SYMBOLIZER_PATH
				alias CC=$CC
				alias CXX=$CXX
				alias CPP=$CPP
				alias AR=$AR
				alias NM=$NM
				alias RANLIB=$RANLIB
			else
				echo "/usr/local/opt/$compiler not found!"
				return 1
			fi
			;;
		llvm*)
			if [ -d "/usr/local/opt/$compiler" ]; then
				export COMPILER=$compiler
				export COMPILER_PATH="/usr/local/opt/$compiler"
				export PATH="$COMPILER_PATH/bin:$(echo "$PATH" | sed -e 's#:/usr/local/opt/[^/]*/bin##')"
				export CC="$(ls $COMPILER_PATH/bin/clang* | head -1)"
				export CXX="$(ls $COMPILER_PATH/bin/clang++* | head -1)"
				export CPP="$(ls $COMPILER_PATH/bin/clang-cpp* | head -1)"
				export AR="$(ls $COMPILER_PATH/bin/llvm-ar* | head -1)"
				export NM="$(ls $COMPILER_PATH/bin/llvm-nm* | head -1)"
				export RANLIB="$(ls $COMPILER_PATH/bin/llvm-ranlib* | head -1)"
				export CFLAGS="-I$COMPILER_PATH/include"
				export CXXFLAGS="-I$COMPILER_PATH/include"
				export CPPFLAGS="-I$COMPILER_PATH/include"
				export LDFLAGS="-L$COMPILER_PATH/lib -Wl,-rpath,$COMPILER_PATH/lib"
				export ASAN_SYMBOLIZER_PATH="$(ls $COMPILER_PATH/bin/llvm-symbolizer* | head -1)"
				export MSAN_SYMBOLIZER_PATH="$(ls $COMPILER_PATH/bin/llvm-symbolizer* | head -1)"
				export TSAN_SYMBOLIZER_PATH="$(ls $COMPILER_PATH/bin/llvm-symbolizer* | head -1)"
				export UBSAN_SYMBOLIZER_PATH="$(ls $COMPILER_PATH/bin/llvm-symbolizer* | head -1)"
				alias CC=$CC
				alias CXX=$CXX
				alias CPP=$CPP
				alias AR=$AR
				alias NM=$NM
				alias RANLIB=$RANLIB
			else
				echo "/usr/local/opt/$compiler not found!"
				return 1
			fi
			;;
		default)
			export PATH="$(echo "$PATH" | sed -e 's#:/usr/local/opt/[^/]*/bin##')"
			unset COMPILER
			unset COMPILER_PATH
			unset CC
			unset CXX
			unset CPP
			unset AR
			unset NM
			unset RANLIB
			unset CFLAGS
			unset CXXFLAGS
			unset CPPFLAGS
			unset LDFLAGS
			unset ASAN_SYMBOLIZER_PATH
			unset MSAN_SYMBOLIZER_PATH
			unset TSAN_SYMBOLIZER_PATH
			unset UBSAN_SYMBOLIZER_PATH
			unalias CC
			unalias CXX
			unalias CPP
			unalias AR
			unalias NM
			unalias RANLIB
			;;
	esac
	if [ -z "$COMPILER" ]; then
		echo "Using default compiler"
	else
		echo "Using $COMPILER compiler"
	fi
}