#
# Regular Definitions
#

rl rl_ws /[ \t\n\r\v]+/
rl rl_id /[a-zA-Z_][a-zA-Z0-9_]*/
rl rl_num /[0-9]+/

#
# Tokens
#

lex
	# Ignore whitespace.
	ignore /rl_ws/

	# Tokens. 
	token id /rl_id/
	token number /rl_num/
end

#
# Productions
#

# Arbitrary item.
def item
	[id]
|	[number]

# List production one. The condition stops the 
# greedy list when it has gone too far.
def count_items
	target: int
	count: int

	[count_items item]
	{
		# Pass up the data
		lhs.target = r1.target
		lhs.count = r1.count + 1

		if lhs.count > lhs.target {
			reject
		}
	}

	# List production two, the base.
|	[number]
	{
		match lhs [Number: number]
		lhs.target = Number.data.atoi()
		lhs.count = 0
	}
		

# Wrapper which prevents short lists from getting through if the parser
# encounters an error and needs to backtrack over counted list.
def counted_list
	[count_items]
	{
		if r1.count < r1.target {
			reject
		}
	}

def start 
	[counted_list*]
	{
		for List: counted_list in lhs {
			match List [CountItems:count_items]
			print( 'num items: ' CountItems.target '\n' )

			i: int = 1
			for Item:item in CountItems {
				print( '  item ' i ': ' ^Item '\n' )
				i = i + 1
			}
		}
	}

parse start[ stdin ]
##### IN #####
3 1 b c 1 1 0 3 a b c
##### EXP #####
num items: 3
  item 1: 1
  item 2: b
  item 3: c
num items: 1
  item 1: 1
num items: 0
num items: 3
  item 1: a
  item 2: b
  item 3: c