HT="$(printf '\t.')";   HT="${HT%.}"
LF="$(printf '\n.')";   LF="${LF%.}"
RS="$(printf '\036.')"; RS="${RS%.}"
US="$(printf '\037.')"; US="${US%.}"

. ./tokens.sh
. ./lexer.sh

complete_command()
{
	if list; then
		separator
		return 0
	fi
	return 1
}

list()
{
	if and_or; then
		while separator_op; do
			if ! and_or; then
				return 1
			fi
		done
		return 0
	fi
	return 1
}
and_or()
{
	if pipeline; then
		while accept T_AND_IF || accept T_OR_IF; do
			if ! linebreak || ! pipeline; then
				return 1
			fi
		done
		return 0
	fi
	return 1
}
pipeline()
{
	accept T_BANG
	if pipe_sequence; then
		return 0
	fi
	return 1
}

pipe_sequence()
{
	if command; then
		while accept T_PIPE; do
			if ! linebreak || ! command; then
				return 1
			fi
		done
		return 0
	fi
	return 1
}

command()
{
	# XXX: Unfinished
	accept T_WORD
}



newline_list()
{
	if accept T_NEWLINE; then
		while accept T_NEWLINE; do
			:
		done
		return 0
	fi
	return 1
}
linebreak()
{
	newline_list
	return 0
}

separator_op()
{
	if accept T_AND || accept T_SEMI; then
		return 0
	fi
	return 1
}

separator()
{
	if separator_op && linebreak; then
		return 0
	elif newline_list; then
		return 0
	fi
	return 1
}

parse()
{
	local fn="${1}"
	shift 1

	init_lexer "${fn}"
	while complete_command; do :; done
	if :; then  # TODO: Test for EOF or errors
		get_tokens
		return 0
	fi
	return 1
}

if tokens="$(printf '%s\n' '"foo bar" && $baz || qux' '${quux%uux } quuux' | \
		parse -)"; then
	IFS="${RS}"
	for t in ${tokens}; do
		printf 'Token: %s\n' "$(tokname "${t}")"
		case "${t%${US}*}" in T_WORD)
			printf '       "%s"\n' "${t#T_WORD${US}}"
			;;
		esac
	done
	unset IFS
else
	echo FAIL
fi