Class: Rbexy::Lexer

Inherits:
Object
  • Object
show all
Defined in:
lib/rbexy/lexer.rb

Defined Under Namespace

Classes: SyntaxError

Constant Summary collapse

Patterns = 
HashMash.new(
  open_expression: /{/,
  close_expression: /}/,
  expression_content: /[^}{"'<]+/,
  open_tag_def: /<(?!\/)/,
  open_tag_end: /<\//,
  close_tag: /\s*\/?>/,
  close_self_closing_tag: /\s*\/>/,
  tag_name: /\/?[A-Za-z0-9\-_.]+/,
  text_content: /[^<{#]+/,
  comment: /^\p{Blank}*#.*(\n|\z)/,
  whitespace: /\s+/,
  attr: /[A-Za-z0-9\-_\.:]+/,
  open_attr_splat: /{\*\*/,
  attr_assignment: /=/,
  double_quote: /"/,
  single_quote: /'/,
  double_quoted_text_content: /[^"]+/,
  single_quoted_text_content: /[^']+/,
  expression_internal_tag_prefixes: /(\s+(&&|\?|:|do|do\s*\|[^\|]+\||{|{\s*\|[^\|]+\|)\s+\z|\A\s*\z)/,
  declaration: /<![^>]*>/
)

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(code) ⇒ Lexer

Returns a new instance of Lexer.



40
41
42
43
44
45
46
47
48
49
 
# File 'lib/rbexy/lexer.rb', line 40

def initialize(code)
  @stack = [:default]
  @curr_expr_bracket_levels = 0
  @curr_expr_quote_levels = { single: 0, double: 0 }
  @curr_expr = ""
  @curr_default_text = ""
  @curr_quoted_text = ""
  @tokens = []
  @scanner = StringScanner.new(code)
end

Instance Attribute Details

#curr_default_text ⇒ Object

Returns the value of attribute curr_default_text.



37
38
39
 
# File 'lib/rbexy/lexer.rb', line 37

def curr_default_text
  @curr_default_text
end

#curr_expr ⇒ Object

Returns the value of attribute curr_expr.



37
38
39
 
# File 'lib/rbexy/lexer.rb', line 37

def curr_expr
  @curr_expr
end

#curr_expr_bracket_levels ⇒ Object

Returns the value of attribute curr_expr_bracket_levels.



37
38
39
 
# File 'lib/rbexy/lexer.rb', line 37

def curr_expr_bracket_levels
  @curr_expr_bracket_levels
end

#curr_expr_quote_levels ⇒ Object (readonly)

Returns the value of attribute curr_expr_quote_levels.



36
37
38
 
# File 'lib/rbexy/lexer.rb', line 36

def curr_expr_quote_levels
  @curr_expr_quote_levels
end

#curr_quoted_text ⇒ Object

Returns the value of attribute curr_quoted_text.



37
38
39
 
# File 'lib/rbexy/lexer.rb', line 37

def curr_quoted_text
  @curr_quoted_text
end

#scanner ⇒ Object (readonly)

Returns the value of attribute scanner.



36
37
38
 
# File 'lib/rbexy/lexer.rb', line 36

def scanner
  @scanner
end

#stack ⇒ Object (readonly)

Returns the value of attribute stack.



36
37
38
 
# File 'lib/rbexy/lexer.rb', line 36

def stack
  @stack
end

#tokens ⇒ Object (readonly)

Returns the value of attribute tokens.



36
37
38
 
# File 'lib/rbexy/lexer.rb', line 36

def tokens
  @tokens
end

Instance Method Details

#expression_content? ⇒ Boolean

Returns:

  • (Boolean) 


279
280
281
282
283
284
285
286
287
288
 
# File 'lib/rbexy/lexer.rb', line 279

def expression_content?
  # Patterns.expression_content ends at `<` characters, because we need to
  # separately scan for allowed open_tag_defs within expressions. We should
  # support any found open_tag_ends as expression content, as that means the
  # open_tag_def was not considered allowed (or stack would be inside
  # :tag_def instead of :expression) so we should thus also consider the
  # open_tag_end to just be a part of the expression (maybe its in a string,
  # etc).
  scanner.scan(Patterns.expression_content) || scanner.scan(Patterns.open_tag_end)
end

#expression_inner_bracket ⇒ Object 



259
260
261
262
 
# File 'lib/rbexy/lexer.rb', line 259

def expression_inner_bracket
  self.curr_expr += scanner.matched
  stack.push(:expression_inner_bracket)
end

#expression_inner_double_quote ⇒ Object 



264
265
266
267
 
# File 'lib/rbexy/lexer.rb', line 264

def expression_inner_double_quote
  self.curr_expr += scanner.matched
  stack.push(:expression_inner_double_quote)
end

#expression_inner_single_quote ⇒ Object 



269
270
271
272
 
# File 'lib/rbexy/lexer.rb', line 269

def expression_inner_single_quote
  self.curr_expr += scanner.matched
  stack.push(:expression_inner_single_quote)
end

#expression_quoted_string_content ⇒ Object 



274
275
276
277
 
# File 'lib/rbexy/lexer.rb', line 274

def expression_quoted_string_content
  self.curr_expr += scanner.getch
  stack.pop unless curr_expr.end_with?('\\')
end

#open_expression ⇒ Object 



254
255
256
257
 
# File 'lib/rbexy/lexer.rb', line 254

def open_expression
  tokens << [:OPEN_EXPRESSION]
  stack.push(:expression)
end

#open_tag_def ⇒ Object 



249
250
251
252
 
# File 'lib/rbexy/lexer.rb', line 249

def open_tag_def
  tokens << [:OPEN_TAG_DEF]
  stack.push(:tag, :tag_def)
end

#potential_expression_inner_tag ⇒ Object 



239
240
241
242
243
244
245
246
247
 
# File 'lib/rbexy/lexer.rb', line 239

def potential_expression_inner_tag
  if self.curr_expr =~ Patterns.expression_internal_tag_prefixes
    tokens << [:EXPRESSION_BODY, curr_expr]
    self.curr_expr = ""
    open_tag_def
  else
    self.curr_expr += scanner.matched
  end
end

#tokenize ⇒ Object 



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
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
 
# File 'lib/rbexy/lexer.rb', line 51

def tokenize
  until scanner.eos?
    case stack.last
    when :default
      if scanner.scan(Patterns.declaration)
        tokens << [:DECLARATION, scanner.matched]
      elsif scanner.scan(Patterns.open_tag_def)
        open_tag_def
      elsif scanner.scan(Patterns.open_expression)
        open_expression
      elsif scanner.scan(Patterns.comment)
        tokens << [:SILENT_NEWLINE]
      elsif scanner.check(Patterns.text_content)
        stack.push(:default_text)
      else
        raise SyntaxError, self
      end
    when :tag
      if scanner.scan(Patterns.open_tag_def)
        open_tag_def
      elsif scanner.scan(Patterns.open_tag_end)
        tokens << [:OPEN_TAG_END]
        stack.push(:tag_end)
      elsif scanner.scan(Patterns.open_expression)
        open_expression
      elsif scanner.scan(Patterns.comment)
        tokens << [:SILENT_NEWLINE]
      elsif scanner.check(Patterns.text_content)
        stack.push(:default_text)
      else
        raise SyntaxError, self
      end
    when :default_text
      if scanner.scan(Patterns.text_content)
        self.curr_default_text += scanner.matched
        if scanner.matched.end_with?('\\') && scanner.peek(1) == "{"
          self.curr_default_text += scanner.getch
        elsif scanner.matched.end_with?('\\') && scanner.peek(1) == "#"
          self.curr_default_text += scanner.getch
        else
          if scanner.peek(1) == "#"
            # If the next token is a comment, trim trailing whitespace from
            # the text value so we don't add to the indentation of the next
            # value that is output after the comment
            self.curr_default_text = curr_default_text.gsub(/^\p{Blank}*\z/, "")
          end
          tokens << [:TEXT, curr_default_text]
          self.curr_default_text = ""
          stack.pop
        end
      else
        raise SyntaxError, self
      end
    when :expression
      if scanner.scan(Patterns.close_expression)
        tokens << [:EXPRESSION_BODY, curr_expr]
        tokens << [:CLOSE_EXPRESSION]
        self.curr_expr = ""
        stack.pop
      elsif scanner.scan(Patterns.open_expression)
        expression_inner_bracket
      elsif scanner.scan(Patterns.double_quote)
        expression_inner_double_quote
      elsif scanner.scan(Patterns.single_quote)
        expression_inner_single_quote
      elsif scanner.scan(Patterns.open_tag_def)
        potential_expression_inner_tag
      elsif expression_content?
        self.curr_expr += scanner.matched
      else
        raise SyntaxError, self
      end
    when :expression_inner_bracket
      if scanner.scan(Patterns.close_expression)
        self.curr_expr += scanner.matched
        stack.pop
      elsif scanner.scan(Patterns.open_expression)
        expression_inner_bracket
      elsif scanner.scan(Patterns.double_quote)
        expression_inner_double_quote
      elsif scanner.scan(Patterns.single_quote)
        expression_inner_single_quote
      elsif scanner.scan(Patterns.open_tag_def)
        potential_expression_inner_tag
      elsif expression_content?
        self.curr_expr += scanner.matched
      else
        raise SyntaxError, self
      end
    when :expression_inner_double_quote
      if scanner.check(Patterns.double_quote)
        expression_quoted_string_content
      elsif scanner.scan(Patterns.double_quoted_text_content)
        self.curr_expr += scanner.matched
      else
        raise SyntaxError, self
      end
    when :expression_inner_single_quote
      if scanner.check(Patterns.single_quote)
        expression_quoted_string_content
      elsif scanner.scan(Patterns.single_quoted_text_content)
        self.curr_expr += scanner.matched
      else
        raise SyntaxError, self
      end
    when :tag_def
      if scanner.scan(Patterns.close_self_closing_tag)
        tokens << [:CLOSE_TAG_DEF]
        tokens << [:OPEN_TAG_END]
        tokens << [:CLOSE_TAG_END]
        stack.pop(2)
      elsif scanner.scan(Patterns.close_tag)
        tokens << [:CLOSE_TAG_DEF]
        stack.pop
      elsif scanner.scan(Patterns.tag_name)
        tokens << [:TAG_NAME, scanner.matched]
      elsif scanner.scan(Patterns.whitespace)
        scanner.matched.count("\n").times { tokens << [:SILENT_NEWLINE] }
        tokens << [:OPEN_ATTRS]
        stack.push(:tag_attrs)
      else
        raise SyntaxError, self
      end
    when :tag_end
      if scanner.scan(Patterns.close_tag)
        tokens << [:CLOSE_TAG_END]
        stack.pop(2)
      elsif scanner.scan(Patterns.tag_name)
        tokens << [:TAG_NAME, scanner.matched]
      else
        raise SyntaxError, self
      end
    when :tag_attrs
      if scanner.scan(Patterns.whitespace)
        scanner.matched.count("\n").times { tokens << [:SILENT_NEWLINE] }
      elsif scanner.check(Patterns.close_tag)
        tokens << [:CLOSE_ATTRS]
        stack.pop
      elsif scanner.scan(Patterns.attr_assignment)
        tokens << [:OPEN_ATTR_VALUE]
        stack.push(:tag_attr_value)
      elsif scanner.scan(Patterns.attr)
        tokens << [:ATTR_NAME, scanner.matched.strip]
      elsif scanner.scan(Patterns.open_attr_splat)
        tokens << [:OPEN_ATTR_SPLAT]
        tokens << [:OPEN_EXPRESSION]
        stack.push(:tag_attr_splat, :expression)
      else
        raise SyntaxError, self
      end
    when :tag_attr_value
      if scanner.scan(Patterns.double_quote)
        stack.push(:quoted_text)
      elsif scanner.scan(Patterns.open_expression)
        open_expression
      elsif scanner.scan(Patterns.whitespace) || scanner.check(Patterns.close_tag)
        tokens << [:CLOSE_ATTR_VALUE]
        scanner.matched.count("\n").times { tokens << [:SILENT_NEWLINE] }
        stack.pop
      else
        raise SyntaxError, self
      end
    when :tag_attr_splat
      # Splat is consumed by :expression. It pops control back to here once
      # it's done, and we just record the completion and pop back to :tag_attrs
      tokens << [:CLOSE_ATTR_SPLAT]
      stack.pop
    when :quoted_text
      if scanner.scan(Patterns.double_quoted_text_content)
        self.curr_quoted_text += scanner.matched
        if scanner.matched.end_with?('\\') && scanner.peek(1) == "\""
          self.curr_quoted_text += scanner.getch
        end
      elsif scanner.scan(Patterns.double_quote)
        tokens << [:TEXT, curr_quoted_text]
        self.curr_quoted_text = ""
        stack.pop
      else
        raise SyntaxError, self
      end
    else
      raise SyntaxError, self
    end
  end

  tokens
end