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String

Sequel extends String to add methods to implement the SQL DSL.


The string_date_time extension provides String instance methods for converting the strings to a date (e.g. String#to_date), allowing for backwards compatibility with legacy Sequel code.


The inflector extension adds inflection instance methods to String, which allows the easy transformation of words from singular to plural, class names to table names, modularized class names to ones without, and class names to foreign keys. It exists for backwards compatibility to legacy Sequel code.

Public Class Methods

inflections() click to toggle source

Yield the Inflections module if a block is given, and return the Inflections module.

# File lib/sequel/extensions/inflector.rb, line 96
def self.inflections
  yield Inflections if block_given?
  Inflections
end

Public Instance Methods

blank?() click to toggle source

Strings are blank if they are empty or include only whitespace

# File lib/sequel/extensions/blank.rb, line 33
def blank?
  strip.empty?
end
camelcase(first_letter_in_uppercase = :upper) click to toggle source
Alias for: camelize
camelize(first_letter_in_uppercase = :upper) click to toggle source

By default, camelize converts the string to UpperCamelCase. If the argument to camelize is set to :lower then camelize produces lowerCamelCase.

camelize will also convert '/' to '::' which is useful for converting paths to namespaces

Examples

"active_record".camelize #=> "ActiveRecord"
"active_record".camelize(:lower) #=> "activeRecord"
"active_record/errors".camelize #=> "ActiveRecord::Errors"
"active_record/errors".camelize(:lower) #=> "activeRecord::Errors"
# File lib/sequel/extensions/inflector.rb, line 111
def camelize(first_letter_in_uppercase = :upper)
  s = gsub(/\/(.?)/){|x| "::#{x[-1..-1].upcase unless x == '/'}"}.gsub(/(^|_)(.)/){|x| x[-1..-1].upcase}
  s[0...1] = s[0...1].downcase unless first_letter_in_uppercase == :upper
  s
end
Also aliased as: camelcase
classify() click to toggle source

Singularizes and camelizes the string. Also strips out all characters preceding and including a period (".").

Examples

"egg_and_hams".classify #=> "EggAndHam"
"post".classify #=> "Post"
"schema.post".classify #=> "Post"
# File lib/sequel/extensions/inflector.rb, line 125
def classify
  sub(/.*\./, '').singularize.camelize
end
constantize() click to toggle source

Constantize tries to find a declared constant with the name specified in the string. It raises a NameError when the name is not in CamelCase or is not initialized.

Examples

"Module".constantize #=> Module
"Class".constantize #=> Class
# File lib/sequel/extensions/inflector.rb, line 136
def constantize
  raise(NameError, "#{inspect} is not a valid constant name!") unless m = /\A(?:::)?([A-Z]\w*(?:::[A-Z]\w*)*)\z/.match(self)
  Object.module_eval("::#{m[1]}", __FILE__, __LINE__)
end
dasherize() click to toggle source

Replaces underscores with dashes in the string.

Example

"puni_puni".dasherize #=> "puni-puni"
# File lib/sequel/extensions/inflector.rb, line 145
def dasherize
  gsub(/_/, '-')
end
demodulize() click to toggle source

Removes the module part from the expression in the string

Examples

"ActiveRecord::CoreExtensions::String::Inflections".demodulize #=> "Inflections"
"Inflections".demodulize #=> "Inflections"
# File lib/sequel/extensions/inflector.rb, line 154
def demodulize
  gsub(/^.*::/, '')
end
foreign_key(use_underscore = true) click to toggle source

Creates a foreign key name from a class name. use_underscore sets whether the method should put '_' between the name and 'id'.

Examples

"Message".foreign_key #=> "message_id"
"Message".foreign_key(false) #=> "messageid"
"Admin::Post".foreign_key #=> "post_id"
# File lib/sequel/extensions/inflector.rb, line 165
def foreign_key(use_underscore = true)
  "#{demodulize.underscore}#{'_' if use_underscore}id"
end
humanize() click to toggle source

Capitalizes the first word and turns underscores into spaces and strips _id. Like titleize, this is meant for creating pretty output.

Examples

"employee_salary" #=> "Employee salary"
"author_id" #=> "Author"
# File lib/sequel/extensions/inflector.rb, line 175
def humanize
  gsub(/_id$/, "").gsub(/_/, " ").capitalize
end
lit(*args) click to toggle source

Converts a string into a Sequel::LiteralString, in order to override string literalization, e.g.:

DB[:items].filter(:abc => 'def').sql #=>
  "SELECT * FROM items WHERE (abc = 'def')"

DB[:items].filter(:abc => 'def'.lit).sql #=>
  "SELECT * FROM items WHERE (abc = def)"

You can also provide arguments, to create a Sequel::SQL::PlaceholderLiteralString:

DB[:items].select{|o| o.count('DISTINCT ?'.lit(:a))}.sql #=>
  "SELECT count(DISTINCT a) FROM items"
# File lib/sequel/core_sql.rb, line 201
def lit(*args)
  args.empty? ? Sequel::LiteralString.new(self) : Sequel::SQL::PlaceholderLiteralString.new(self, args)
end
pluralize() click to toggle source

Returns the plural form of the word in the string.

Examples

"post".pluralize #=> "posts"
"octopus".pluralize #=> "octopi"
"sheep".pluralize #=> "sheep"
"words".pluralize #=> "words"
"the blue mailman".pluralize #=> "the blue mailmen"
"CamelOctopus".pluralize #=> "CamelOctopi"
# File lib/sequel/extensions/inflector.rb, line 188
def pluralize
  result = dup
  Inflections.plurals.each{|(rule, replacement)| break if result.gsub!(rule, replacement)} unless Inflections.uncountables.include?(downcase)
  result
end
singularize() click to toggle source

The reverse of pluralize, returns the singular form of a word in a string.

Examples

"posts".singularize #=> "post"
"octopi".singularize #=> "octopus"
"sheep".singluarize #=> "sheep"
"word".singluarize #=> "word"
"the blue mailmen".singularize #=> "the blue mailman"
"CamelOctopi".singularize #=> "CamelOctopus"
# File lib/sequel/extensions/inflector.rb, line 203
def singularize
  result = dup
  Inflections.singulars.each{|(rule, replacement)| break if result.gsub!(rule, replacement)} unless Inflections.uncountables.include?(downcase)
  result
end
sql_expr() click to toggle source

Returns a copy of the object wrapped in a Sequel::SQL::StringExpression, allowing easy use of Sequel's DSL:

"a".sql_expr + :a  # 'a' || a
# File lib/sequel/extensions/sql_expr.rb, line 107
def sql_expr
  Sequel::SQL::StringExpression.new(:NOOP, self)
end
tableize() click to toggle source

Underscores and pluralizes the string.

Examples

"RawScaledScorer".tableize #=> "raw_scaled_scorers"
"egg_and_ham".tableize #=> "egg_and_hams"
"fancyCategory".tableize #=> "fancy_categories"
# File lib/sequel/extensions/inflector.rb, line 215
def tableize
  underscore.pluralize
end
titlecase() click to toggle source
Alias for: titleize
titleize() click to toggle source

Capitalizes all the words and replaces some characters in the string to create a nicer looking title. Titleize is meant for creating pretty output.

titleize is also aliased as as titlecase

Examples

"man from the boondocks".titleize #=> "Man From The Boondocks"
"x-men: the last stand".titleize #=> "X Men: The Last Stand"
# File lib/sequel/extensions/inflector.rb, line 227
def titleize
  underscore.humanize.gsub(/\b([a-z])/){|x| x[-1..-1].upcase}
end
Also aliased as: titlecase
to_date() click to toggle source

Converts a string into a Date object.

# File lib/sequel/extensions/string_date_time.rb, line 7
def to_date
  begin
    Date.parse(self, Sequel.convert_two_digit_years)
  rescue => e
    raise Sequel.convert_exception_class(e, Sequel::InvalidValue)
  end
end
to_datetime() click to toggle source

Converts a string into a DateTime object.

# File lib/sequel/extensions/string_date_time.rb, line 16
def to_datetime
  begin
    DateTime.parse(self, Sequel.convert_two_digit_years)
  rescue => e
    raise Sequel.convert_exception_class(e, Sequel::InvalidValue)
  end
end
to_sequel_blob() click to toggle source

Returns a Sequel::SQL::Blob that holds the same data as this string. Blobs provide proper escaping of binary data.

# File lib/sequel/core_sql.rb, line 207
def to_sequel_blob
  ::Sequel::SQL::Blob.new(self)
end
to_sequel_time() click to toggle source

Converts a string into a Time or DateTime object, depending on the value of Sequel.datetime_class

# File lib/sequel/extensions/string_date_time.rb, line 26
def to_sequel_time
  begin
    if Sequel.datetime_class == DateTime
      DateTime.parse(self, Sequel.convert_two_digit_years)
    else
      Sequel.datetime_class.parse(self)
    end
  rescue => e
    raise Sequel.convert_exception_class(e, Sequel::InvalidValue)
  end
end
to_time() click to toggle source

Converts a string into a Time object.

# File lib/sequel/extensions/string_date_time.rb, line 39
def to_time
  begin
    Time.parse(self)
  rescue => e
    raise Sequel.convert_exception_class(e, Sequel::InvalidValue)
  end
end
underscore() click to toggle source

The reverse of camelize. Makes an underscored form from the expression in the string. Also changes '::' to '/' to convert namespaces to paths.

Examples

"ActiveRecord".underscore #=> "active_record"
"ActiveRecord::Errors".underscore #=> active_record/errors
# File lib/sequel/extensions/inflector.rb, line 238
def underscore
  gsub(/::/, '/').gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2').
    gsub(/([a-z\d])([A-Z])/,'\1_\2').tr("-", "_").downcase
end

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