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.
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
Strings are blank if they are empty or include only whitespace
# File lib/sequel/extensions/blank.rb, line 33 def blank? strip.empty? end
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
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 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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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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