Records - Frozen / Immutable Structs with Copy on Updates

records gem / library - frozen / immutable structs with copy on updates

• home :: github.com/s6ruby/records
• bugs :: github.com/s6ruby/records/issues
• gem :: rubygems.org/gems/records
• rdoc :: rubydoc.info/gems/records

Usage

Use Record.new like Struct.new to build / create a new frozen / immutable record class. Example:

Record.new( :Account,
              balance:    Integer,
              allowances: Hash )

# -or-

Record.new :Account,
              balance:    Integer,
              allowances: Hash

# -or-

Record.new :Account, { balance:    Integer,
                       allowances: Hash }

# -or-

class Account < Record::Base
  field :balance,    Integer
  field :allowances, Hash
end

And use the new record class like:

account1a  = Account.new( 1, {} )
account1a.frozen?            #=> true
account1a.values.frozen?     #=> true
account1a.balance            #=> 1
account1a.allowances         #=> {}
account1a.values             #=> [1, {}]

Account.keys                 #=> [:balance, :allowances]
Account.fields               #=> [<Field @key=:balance, @index=0, @type=Integer>,
                             #    <Field @key=:allowances, @index=1, @type=Hash>]
Account.index( :balance )    #=> 0
Account.index( :allowances ) #=> 1

Note: The update method (or the << alias) ALWAYS returns a new record.

account1a.update( balance: 20 )     #=> [20, {}]
account1a.update( balance: 30 )     #=> [30, {}]
account1a.update( { balance: 30 } ) #=> [30, {}]

account1a << { balance: 20 }        #=> [20, {}]
account1a << { balance: 30 }        #=> [30, {}]

account1b = account1a.update( balance: 40, allowances: { 'Alice': 20 } )
account1b.balance                   #=> 40
account1b.allowances                #=> { 'Alice': 20 }
account1b.values                    #=> [40, { 'Alice': 20 } ]
# ...

And so on and so forth.

Bonus - Record Update Language Syntax Pragmas - {...} and ={...}

Using the Record Update Pragma. Lets you

account1a {... balance: 20 }     #=> [20, {}]
account1a {... balance: 30 }     #=> [30, {}]

account1a = {... balance: 40, allowances: { 'Alice': 20 }}

turn into:

account1a.update( balance: 20 )     #=> [20, {}]
account1a.update( balance: 30 )     #=> [30, {}]

account1a = account1a.update( balance: 40, allowances: { 'Alice': 20 } )

See Language Syntax Pragmas - Let's Evolve Ruby by Experimenting in a Pragma(tic) Way for more.

License

The records scripts are dedicated to the public domain. Use it as you please with no restrictions whatsoever.

Questions? Comments?

Send them along to the wwwmake forum. Thanks!