blob: b9c1522afff327d22decdcf946d139c7f4c19fb1 (
plain)
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
|
module Lrama
class Parser
class TokenScanner
def initialize(tokens)
@tokens = tokens
@index = 0
end
def current_token
@tokens[@index]
end
def current_type
current_token && current_token.type
end
def next
token = current_token
@index += 1
return token
end
def consume(*token_types)
if token_types.include?(current_type)
token = current_token
self.next
return token
end
return nil
end
def consume!(*token_types)
consume(*token_types) || (raise "#{token_types} is expected but #{current_type}. #{current_token}")
end
def consume_multi(*token_types)
a = []
while token_types.include?(current_type)
a << current_token
self.next
end
raise "No token is consumed. #{token_types}" if a.empty?
return a
end
def eots?
current_token.nil?
end
end
end
end
|
