1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
|
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]
parse S: start(stdin)
#
# Fixed point iteration
#
bool this_iter_modified()
{ return true }
iter fixed_point( T: ref any )
{
modified: bool = 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' )
|
