lex start
{
	ignore /[\t\n ]+/
	literal '^', '|', '-', ',', ':', '!', '?', '.'
	literal '(', ')', '{', '}', '*', '&', '+'

	literal '--', ':>', ':>>', '<:', '->', '**'

	token word /[a-zA-Z_][a-zA-Z0-9_]*/
	token uint /[0-9]+/
}


def start 
	[expression]

def expression [term expression_op*]

def expression_op
	['|' term]
|	['&' term]
|	['-' term]
|	['--' term]

def term [factor_rep term_rest]

# This list is done manually to get shortest match.
def term_rest
	[]
|	[term_op term_rest]

def term_op
	[factor_rep]
|	['.' factor_rep]
|	[':>' factor_rep]
|	[':>>' factor_rep]
|	['<:' factor_rep]

def factor_rep 
	[factor_neg factor_rep_op*]

def factor_rep_op
	['*']
|	['**']
|	['?']
|	['+']
|	['{' factor_rep_num '}']
|	['{' ',' factor_rep_num '}']
|	['{' factor_rep_num ',' '}']
|	['{' factor_rep_num ',' factor_rep_num '}']

def factor_rep_num [uint]

def factor_neg 
	['!' factor_neg]
|	['^' factor_neg]
|	[factor]

def factor 
	[alphabet_num]
|	[word]
|	['(' expression ')']

def alphabet_num 
	[uint]

start S = parse start(stdin)

#
# Fixed point iteration
#

bool this_iter_modified()
	{ return true }

iter fixed_point( ref any T )
{
	bool modified = true
	while modified {
		modified = false
		for S:any in T {
			yield S

			if this_iter_modified() {
				modified = true
				break
			}
		}
	}
}


for T: any in fixed_point( S ) 
{
	print( T '\n' )
}

print( S '\n' )