module Gorillib::Hashlike::HashlikeViaAccessors

Makes a Receiver thingie behave mostly like a hash.

By default, the hashlike methods iterate over the receiver attributes: instance keys delegates to self.class.keys which calls receiver_attr_names. If you want to filter our add to the keys list, you can just override the class-level keys method (and call super, or not):

def self.keys
  super + [:firstname, :lastname] - [:fullname]
end

in addition to the below, by including Enumerable, this also adds

:each_cons, :each_entry, :each_slice, :each_with_index, :each_with_object,
:map, :collect, :collect_concat, :entries, :to_a, :flat_map, :inject, :reduce,
:group_by, :chunk, :cycle, :partition, :reverse_each, :slice_before, :drop,
:drop_while, :take, :take_while, :detect, :find, :find_all, :find_index, :grep,
:all?, :any?, :none?, :one?, :first, :count, :zip :max, :max_by, :min, :min_by,
:minmax, :minmax_by, :sort, :sort_by

As opposed to hash, does not define

default, default=, default_proc, default_proc=, shift, flatten, compare_by_identity
compare_by_identity? rehash

Public Instance Methods

[](key) click to toggle source

Hashlike#[]

Element Reference – Retrieves the value stored for key.

In a normal hash, a default value can be set; none is provided here.

Delegates to self.send(key)

@example

hsh = { :a => 100, :b => 200 }
hsh[:a] # => 100
hsh[:c] # => nil

@param key [Object] key to retrieve @return [Object] the value stored for key, nil if missing

# File lib/gorillib/hashlike/hashlike_via_accessors.rb, line 48
def [](key)
  key = convert_key(key)
  self.send(key)
end
[]=(key, val) click to toggle source

Hashlike#[]= Hashlike#store

Element Assignment – Associates the value given by val with the key given by key.

key should not have its value changed while it is in use as a key. In a normal hash, a String passed as a key will be duplicated and frozen. No such guarantee is provided here

Delegates to self.send(“key=”, val)

@example

hsh = { :a => 100, :b => 200 }
hsh[:a] = 9
hsh[:c] = 4
hsh    # => { :a => 9, :b => 200, :c => 4 }

hsh[key] = val                         -> val
hsh.store(key, val)                    -> val

@param key [Object] key to associate @param val [Object] value to associate it with @return [Object]

# File lib/gorillib/hashlike/hashlike_via_accessors.rb, line 78
def []=(key, val)
  key = convert_key(key)
  self.send("#{key}=", val)
end
delete(key, &block) click to toggle source

Hashlike#delete

Deletes and returns the value from hsh whose key is equal to key. If the optional code block is given and the key is not found, pass in the key and return the result of block.

In a normal hash, a default value can be set; none is provided here.

@example

hsh = { :a => 100, :b => 200 }
hsh.delete(:a)                            # => 100
hsh.delete(:z)                            # => nil
hsh.delete(:z){|el| "#{el} not found" }   # => "z not found"

@overload hsh.delete(key) -> val

@param  key [Object] key to remove
@return [Object, Nil] the removed object, nil if missing

@overload hsh.delete(key){|key| block } -> val

@param  key [Object] key to remove
@yield  [Object] called (with key) if key is missing
@yieldparam key
@return [Object, Nil] the removed object, or if missing, the return value
  of the block
# File lib/gorillib/hashlike/hashlike_via_accessors.rb, line 108
def delete(key, &block)
  key = convert_key(key)
  if has_key?(key)
    val = self[key]
    self.send(:remove_instance_variable, "@#{key}")
    val
  elsif block_given?
    block.call(key)
  else
    nil
  end
end
keys() click to toggle source

Hashlike#keys

Returns a new array populated with the keys from this hashlike.

@see Hashlike#values.

@example

hsh = { :a => 100, :b => 200, :c => 300, :d => 400 }
hsh.keys   # => [:a, :b, :c, :d]

@return [Array] list of keys

# File lib/gorillib/hashlike/hashlike_via_accessors.rb, line 157
def keys
  instance_variables.map{|s| convert_key(s[1..-1]) }
end

Protected Instance Methods

convert_key(key) click to toggle source
# File lib/gorillib/hashlike/hashlike_via_accessors.rb, line 162
def convert_key(key)
  raise ArgumentError, "Keys for #{self.class} must be symbols, strings or respond to #to_sym" unless key.respond_to?(:to_sym)
  key.to_sym
end