1+ require 'set'
2+
3+ module CodeRay
4+ module Scanners
5+ module RougeScannerDSL
6+ NoStatesError = Class . new StandardError
7+
8+ State = Struct . new :name , :rules do
9+ def initialize ( name , &block )
10+ super name , [ ]
11+
12+ instance_eval ( &block )
13+ end
14+
15+ def code scanner
16+ <<-RUBY
17+ when #{ name . inspect }
18+ #{ rules_code ( scanner ) . chomp . gsub ( /^/ , ' ' ) }
19+ else
20+ encoder.text_token getch, :error
21+ end
22+ RUBY
23+ end
24+
25+ def rules_code scanner , first : true
26+ raise 'no rules defined for %p' % [ self ] if rules . empty?
27+
28+ [
29+ rules . first . code ( scanner , first : first ) ,
30+ *rules . drop ( 1 ) . map { |rule | rule . code ( scanner ) }
31+ ] . join
32+ end
33+
34+ protected
35+
36+ # DSL
37+
38+ def rule pattern , token = nil , next_state = nil , &block
39+ unless token || block
40+ raise 'please pass `rule` a token to yield or a callback'
41+ end
42+
43+ case token
44+ when Class
45+ unless token < Rouge ::Token
46+ raise "invalid token: #{ token . inspect }
47+ end
48+
49+ case next_state
50+ when Symbol
51+ rules << Rule . new ( pattern , token , next_state )
52+ when nil
53+ rules << Rule . new ( pattern , token )
54+ else
55+ raise "invalid next state: #{ next_state . inspect }
56+ end
57+ when nil
58+ rules << CallbackRule . new ( pattern , block )
59+ else
60+ raise "invalid token: #{ token . inspect }
61+ end
62+ end
63+
64+ def mixin state_name
65+ rules << Mixin . new ( state_name )
66+ end
67+ end
68+
69+ Rule = Struct . new :pattern , :token , :action do
70+ def initialize ( pattern , token , action = nil )
71+ super
72+ end
73+
74+ def code scanner , first : false
75+ <<-RUBY + action_code . to_s
76+ #{ 'els' unless first } #{ pattern . inspect }
77+ encoder.text_token match, #{ token . token_chain . map ( &:name ) . join ( '::' ) }
78+ RUBY
79+ end
80+
81+ def action_code
82+ case action
83+ when :pop!
84+ <<-RUBY
85+ states.pop
86+ state = states.last
87+ RUBY
88+ when Symbol
89+ <<-RUBY
90+ state = #{ action . inspect }
91+ states << state
92+ RUBY
93+ end
94+ end
95+ end
96+
97+ CallbackRule = Struct . new :pattern , :callback do
98+ def code scanner , first : false
99+ <<-RUBY
100+ #{ 'els' unless first } #{ pattern . inspect }
101+ @match = match
102+ #{ scanner . add_callback ( callback ) }
103+ RUBY
104+ end
105+ end
106+
107+ Mixin = Struct . new ( :state_name ) do
108+ def code scanner , first : false
109+ scanner . states [ state_name ] . rules_code ( scanner , first : first )
110+ end
111+ end
112+
113+ attr_accessor :states
114+
115+ def state name , &block
116+ @states ||= { }
117+ @states [ name ] = State . new ( name , &block )
118+ end
119+
120+ def add_callback block
121+ base_name = "__callback_line_#{ block . source_location . last }
122+ callback_name = base_name
123+ counter = 'a'
124+ while callbacks . key? ( callback_name )
125+ callback_name = "#{ base_name } #{ counter }
126+ counter = counter . succ
127+ end
128+
129+ callbacks [ callback_name ] = define_method ( callback_name , &block )
130+
131+ parameters = block . parameters
132+
133+ if parameters . empty?
134+ callback_name
135+ else
136+ parameter_names = parameters . map do |type , name |
137+ raise "callbacks don't allow rest parameters: %p" % [ parameters ] unless type == :req || type == :opt
138+ name = :match if name == :m
139+ name
140+ end
141+
142+ parameter_names . each { |name | variables << name }
143+ "#{ callback_name } #{ parameter_names . join ( ', ' ) }
144+ end
145+ end
146+
147+ def add_variable name
148+ variables << name
149+ end
150+
151+ protected
152+
153+ def callbacks
154+ @callbacks ||= { }
155+ end
156+
157+ def variables
158+ @variables ||= Set . new
159+ end
160+
161+ def additional_variables
162+ variables - %i( encoder options state states match kind )
163+ end
164+
165+ def scan_tokens_code
166+ <<-"RUBY"
167+ state = options[:state] || @state
168+ states = [state]
169+ #{ restore_local_variables_code }
170+ until eos?
171+ case state
172+ #{ states_code . chomp . gsub ( /^/ , ' ' ) }
173+ else
174+ raise_inspect 'Unknown state: %p' % [state], encoder
175+ end
176+ end
177+
178+ @state = state if options[:keep_state]
179+
180+ close_groups(encoder, states)
181+
182+ encoder
183+ RUBY
184+ end
185+
186+ def restore_local_variables_code
187+ additional_variables . sort . map { |name | "#{ name } #{ name } } . join ( "\n " )
188+ end
189+
190+ def states_code
191+ unless defined? ( @states ) && !@states . empty?
192+ raise NoStatesError , 'no states defined for %p' % [ self . class ]
193+ end
194+
195+ @states . values . map { |state | state . code ( self ) } . join
196+ end
197+ end
198+ end
199+ end
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