Class: Sequel::Postgres::HStore

Inherits:
Hash
  • Object
show all
Defined in:
lib/hstore/hstore.rb

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(hash) ⇒ HStore

Returns a new instance of HStore.



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# File 'lib/hstore/hstore.rb', line 47

def initialize(hash)
  @hash = hash
end

Class Method Details

.new_from_string(string) ⇒ Object 



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# File 'lib/hstore/hstore.rb', line 28

def self.new_from_string(string)
  hash = {}

  # remove single quotes around literal if necessary
  string = string[1..-2] if string[0] == "'" and string[-1] == "'"

  scanner = StringScanner.new(string)
  while !scanner.eos?
    k = parse_quotable_string(scanner)
    skip_key_value_delimiter(scanner)
    v = parse_quotable_string(scanner)
    skip_pair_delimiter(scanner)
    # controversial...
    # to_sym, or what?
    hash[k.to_sym] = v
  end
  self[hash]
end

.parse_quotable_string(scanner) ⇒ Object 



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# File 'lib/hstore/hstore.rb', line 10

def self.parse_quotable_string(scanner)
  if scanner.scan(/"/)
    value = quoted_string(scanner)
  else
    value = scanner.scan(/\w+/)
    value = nil if value == "NULL"
    # TODO: values but not keys may be NULL
  end
end

.quoted_string(scanner) ⇒ Object 



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# File 'lib/hstore/hstore.rb', line 4

def self.quoted_string(scanner)
  key = scanner.scan(/(\\"|[^"])*/)
  key = key.gsub(/\\(.)/, '\1')
  scanner.skip(/"/)
  key
end

.skip_key_value_delimiter(scanner) ⇒ Object 



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# File 'lib/hstore/hstore.rb', line 20

def self.skip_key_value_delimiter(scanner)
  scanner.skip(/\s*=>\s*/) 
end

.skip_pair_delimiter(scanner) ⇒ Object 



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# File 'lib/hstore/hstore.rb', line 24

def self.skip_pair_delimiter(scanner)
  scanner.skip(/,\s*/)
end

Instance Method Details

#sql_literal(dataset) ⇒ Object 



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# File 'lib/hstore/hstore.rb', line 55

def sql_literal(dataset)
  string = self.map do |(k,v)|
    if v.nil?
      # represent nil as NULL without quotes
      v = "NULL"
    else
      # otherwise, write a double-quoted string with backslash escapes for quotes
      v = to_s_escaped(v)
      v = "\"#{v}\""
    end

    # TODO: throw an error if there is a NULL key
    "\"#{to_s_escaped(k)}\" => #{v}"
  end.join(", ")
  "'#{string}'"
end

#to_s_escaped(str) ⇒ Object 



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# File 'lib/hstore/hstore.rb', line 51

def to_s_escaped(str)
  str.to_s.gsub(/\\(?!")/) {'\\\\'}.gsub(/"/, '\"').gsub(/'/, "''")
end