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
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
|
$:.unshift File.dirname(__FILE__) + "/../lib"
require 'parslet'
require 'parslet/convenience'
# This example demonstrates tree error reporting in a real life example.
# The parser code has been contributed by John Mettraux.
def prettify(str)
puts " "*3 + " "*4 + "." + " "*4 + "10" + " "*3 + "." + " "*4 + "20"
str.lines.each_with_index do |line, index|
printf "%02d %s\n",
index+1,
line.chomp
end
end
class Parser < Parslet::Parser
# commons
rule(:space) { match('[ \t]').repeat(1) }
rule(:space?) { space.maybe }
rule(:newline) { match('[\r\n]') }
rule(:comment) { str('#') >> match('[^\r\n]').repeat }
rule(:line_separator) {
(space? >> ((comment.maybe >> newline) | str(';')) >> space?).repeat(1)
}
rule(:blank) { line_separator | space }
rule(:blank?) { blank.maybe }
rule(:identifier) { match('[a-zA-Z0-9_]').repeat(1) }
# res_statement
rule(:reference) {
(str('@').repeat(1,2) >> identifier).as(:reference)
}
rule(:res_action_or_link) {
str('.').as(:dot) >> (identifier >> str('?').maybe ).as(:name) >> str('()')
}
rule(:res_actions) {
(
reference
).as(:resources) >>
(
res_action_or_link.as(:res_action)
).repeat(0).as(:res_actions)
}
rule(:res_statement) {
res_actions >>
(str(':') >> identifier.as(:name)).maybe.as(:res_field)
}
# expression
rule(:expression) {
res_statement
}
# body
rule(:body) {
(line_separator >> (block | expression)).repeat(1).as(:body) >>
line_separator
}
# blocks
rule(:begin_block) {
(str('concurrent').as(:type) >> space).maybe.as(:pre) >>
str('begin').as(:begin) >>
body >>
str('end')
}
rule(:define_block) {
str('define').as(:define) >> space >>
identifier.as(:name) >> str('()') >>
body >>
str('end')
}
rule(:block) {
define_block | begin_block
}
# root
rule(:radix) {
line_separator.maybe >> block >> line_separator.maybe
}
root(:radix)
end
ds = [
%{
define f()
@res.name
end
},
%{
define f()
begin
@res.name
end
end
}
]
ds.each do |d|
puts '-' * 80
prettify(d)
parser = Parser.new
begin
parser.parse_with_debug(d)
end
end
puts '-' * 80
|
