Class: LookupHash

Inherits:
Hash
  • Object
show all
Defined in:
lib/lookup-hash.rb

Overview

Hash intended for using as fast lookup table for simply checking of an existency of some item. It doesn’t bring any additional performance, it’s defacto only Hash with Booleans, but it’s better write:

allowed = LookupHash[:alfa, :beta]

than:

allowed = Hash[:alfa, true, :beta, true]

Direct Known Subclasses

Frozen::LookupHash

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ LookupHash

Note:

All values will be converted using hash-utils Hash#to_b to Boolean in the LookupHash. Assigning of default value block isn’t allowed.

Returns a new, empty hash. If this hash is subsequently accessed by a key that doesn‘t correspond to a hash entry, the value returned depends on the style of new used to create the hash. In the first form, the access returns nil. If obj is specified, this single object will be used for all default values. If a block is specified, it will be called with the hash object and the key, and should return the default value. It is the block‘s responsibility to store the value in the hash if required.

See Also:



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# File 'lib/lookup-hash.rb', line 58

def initialize
    super(false)
    self.map_values! { |v| v.to_b }
end

Class Method Details

.[](*args) ⇒ Hash

Creates lookup hash. Expects key names as input. If array given, treat it as just array of keys.

Returns:

  • (Hash) —

    new hash



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# File 'lib/lookup-hash.rb', line 26

def self.[](*args)
    if args.first.kind_of? Array
        args = args.first
    end
    
    new = [ ]
    args.each do |i|
        new << [i, true]
    end
    
    result = super(new)
    result.default = false
    
    return result
end

Instance Method Details

#<<(key) ⇒ Object Also known as: add

Adds key to lookup hash.

Parameters:

  • key (Object) —

    key for add



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# File 'lib/lookup-hash.rb', line 95

def <<(key)
    self[key] = true
end

#[]=(key, value) ⇒ Object

Note:

Value will be converted using hash-utils Hash#to_b to Boolean in the LookupHash.

Element Assignment—Associates the value given by value with the key given by key. key should not have its value changed while it is in use as a key (a String passed as a key will be duplicated and frozen).

See Also:



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# File 'lib/lookup-hash.rb', line 74

def []=(key, value)
    super(key, value.to_b)
end

#default=(value) ⇒ Object

Bans set the default value.



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# File 'lib/lookup-hash.rb', line 105

def default=
end

#default_proc=(value) ⇒ Object

Bans set the default block.



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# File 'lib/lookup-hash.rb', line 120

def default_proc=(value)
end

#replace(other_hash) ⇒ Object

Note:

Value will be converted using hash-utils Hash#to_b to Boolean in the LookupHash.

Replaces the contents of Hash with the contents of other_hash.

See Also:



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# File 'lib/lookup-hash.rb', line 86

def replace(other_hash)
    super(other_hash.map_values { |v| v.to_b })
end