Class: Tr8n::RulesEngine::Parser

Inherits:
Object
  • Object
show all
Defined in:
lib/tr8n/rules_engine/parser.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(expression) ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/tr8n/rules_engine/parser.rb', line 31

def initialize(expression)
  @expression = expression
  if expression =~ /^\(/
    @tokens = expression.scan(/[()]|\w+|@\w+|[\+\-\!\|\=>&<\*\/%]+|".*?"|'.*?'/)
  end
end

Instance Attribute Details

#expression ⇒ Object (readonly)

Returns the value of attribute expression.



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# File 'lib/tr8n/rules_engine/parser.rb', line 29

def expression
  @expression
end

#tokens ⇒ Object (readonly)

Returns the value of attribute tokens.



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# File 'lib/tr8n/rules_engine/parser.rb', line 29

def tokens
  @tokens
end

Instance Method Details

#parse ⇒ Object 



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# File 'lib/tr8n/rules_engine/parser.rb', line 38

def parse
  return @expression unless tokens
  token = tokens.shift
  return nil if token.nil?
  return parse_list if (token) == '('
  return token[1..-2].to_s if token =~ /^['"].*/
  return token.to_i if token =~ /\d+/
  token.to_s
end

#parse_list ⇒ Object 



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# File 'lib/tr8n/rules_engine/parser.rb', line 48

def parse_list
  list = []
  list << parse until tokens.empty? or tokens.first == ')'
  tokens.shift
  list
end