Class: JSONP3::Lexer

Inherits:
Object
  • Object
show all
Defined in:
lib/json_p3/lexer.rb

Overview

JSONPath query expression lexical scanner.

See Also:

Constant Summary collapse

RE_INT = 
/-?[0-9]+/
RE_NAME = 
/[\u0080-\uFFFFa-zA-Z_][\u0080-\uFFFFa-zA-Z0-9_-]*/
RE_WHITESPACE = 
/[ \n\r\t]+/
S_ESCAPES = 
Set["b", "f", "n", "r", "t", "u", "/", "\\"].freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(query) ⇒ Lexer

Returns a new instance of Lexer.



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# File 'lib/json_p3/lexer.rb', line 38

def initialize(query)
  @filter_depth = 0
  @paren_stack = []
  @tokens = []
  @start = 0
  @query = query.freeze
  @scanner = StringScanner.new(query)
end

Instance Attribute Details

#tokens ⇒ Object (readonly)

Returns the value of attribute tokens.



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# File 'lib/json_p3/lexer.rb', line 36

def tokens
  @tokens
end

Class Method Details

.lex_string_factory(quote, state, token) ⇒ Object 



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# File 'lib/json_p3/lexer.rb', line 375

def lex_string_factory(quote, state, token)
  proc {
    # @type self: Lexer
    ignore # move past opening quote

    loop do
      c = self.next

      case c
      when ""
        error "unclosed string starting at index #{@start}"
        return nil
      when "\\"
        peeked = peek
        if S_ESCAPES.member?(peeked) || peeked == quote
          self.next
        else
          error "invalid escape"
          return nil
        end
      when quote
        backup
        emit(token)
        self.next
        ignore # move past closing quote
        return state
      end
    end
  }
end

Instance Method Details

#run ⇒ Object 



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# File 'lib/json_p3/lexer.rb', line 47

def run
  state = :lex_root
  state = send(state) until state.nil?
end