Class: Ensconce::HashBuilder

Inherits:
Object
  • Object
show all
Defined in:
lib/ensconce/hash_builder.rb

Overview

Used to convert pairs of arrays into a hash.

hash_builder = HashBuilder.new :keys => ['a', 'b'], :values => ['1', '2']
hash_builder.hash   --> {'a' => '1', 'b' => '2'}

Also allows modification of keys or values

hash_builder.keys_mod = lambda {|key| key.upcase}
hash_builder.hash   --> {'A' => '1', 'B' => '2'}

hash_builder.values_mod = lambda {|value| (value.to_i * 4).to_s}
hash_builder.hash   --> {'A' => '4', 'B' => '8'}

You can use a Proc to define a mod, but I’d recommend not doing so as a return statement in the Proc can cause an unexpected result (see tests).

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(args = {}) ⇒ HashBuilder

Returns a new instance of HashBuilder.



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# File 'lib/ensconce/hash_builder.rb', line 23

def initialize(args = {})
  @keys = args[:keys]
  @values = args[:values]
  @keys_mod = args[:keys_mod]
  @values_mod = args[:values_mod]
end

Instance Attribute Details

#keys ⇒ Object

Returns the value of attribute keys.



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# File 'lib/ensconce/hash_builder.rb', line 21

def keys
  @keys
end

#keys_mod ⇒ Object

Returns the value of attribute keys_mod.



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# File 'lib/ensconce/hash_builder.rb', line 21

def keys_mod
  @keys_mod
end

#values ⇒ Object

Returns the value of attribute values.



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# File 'lib/ensconce/hash_builder.rb', line 21

def values
  @values
end

#values_mod ⇒ Object

Returns the value of attribute values_mod.



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# File 'lib/ensconce/hash_builder.rb', line 21

def values_mod
  @values_mod
end

Instance Method Details

#check_mods_are_valid ⇒ Object 



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# File 'lib/ensconce/hash_builder.rb', line 41

def check_mods_are_valid
  mod_attributes.each do |mod|
    mod = send mod
    next unless mod
    raise ":#{mod} must be a Proc or lambda" unless mod.kind_of? Proc
  end
end

#check_required_attributes_present ⇒ Object 



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# File 'lib/ensconce/hash_builder.rb', line 49

def check_required_attributes_present
  required_attibutes.each do |attribute|
    raise ":#{attribute} is a required attribute but was not found" unless send(attribute)
  end
end

#hash ⇒ Object 



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# File 'lib/ensconce/hash_builder.rb', line 35

def hash
  valid?
  map = [processed_keys, processed_values].transpose
  Hash[map]
end

#mod_attributes ⇒ Object 



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# File 'lib/ensconce/hash_builder.rb', line 59

def mod_attributes
  [:keys_mod, :values_mod]
end

#processed_keys ⇒ Object 



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# File 'lib/ensconce/hash_builder.rb', line 63

def processed_keys
  keys_mod ? keys.collect(&keys_mod) : keys
end

#processed_values ⇒ Object 



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# File 'lib/ensconce/hash_builder.rb', line 67

def processed_values
  values_mod ? values.collect(&values_mod) : values
end

#required_attibutes ⇒ Object 



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# File 'lib/ensconce/hash_builder.rb', line 55

def required_attibutes
  [:keys, :values]
end

#valid? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ensconce/hash_builder.rb', line 30

def valid?
  check_required_attributes_present
  check_mods_are_valid
end