Module: Hashmake::HashMakeable

Defined in:
lib/hashmake/hash_makeable.rb

Overview

This module should be included for any class that wants to be ‘hash-makeable’, which means that a new object instance expects all its arguments to come in a single Hash. See the hash_make method in this module and the ArgSpec class for more details.

Defined Under Namespace

Modules: ClassMethods

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object

Use the included hook to also extend the including class with HashMake class methods



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# File 'lib/hashmake/hash_makeable.rb', line 16

def self.included(base)
  base.extend(ClassMethods)
end

Instance Method Details

#find_arg_specs ⇒ Object

Look in the current class for a constant that is a Hash containing (only) ArgSpec objects. Returns the first constant matching this criteria, or nil if none was found.



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# File 'lib/hashmake/hash_makeable.rb', line 61

def find_arg_specs
  self.class.constants.each do |constant|
    val = self.class.const_get(constant)
    if val.is_a? Hash
      all_arg_specs = true
      val.each do |key,value|
        unless value.is_a? ArgSpec or value.is_a? ArrayArgSpec or value.is_a?(HashArgSpec)
          all_arg_specs = false
          break
        end
      end
      
      if all_arg_specs
        return val
      end
    end
  end
  
  return nil
end

#hash_make(hashed_args, arg_specs = find_arg_specs, assign_args = true) ⇒ Object

Process a hash that contains ‘hashed args’. Each hashed arg is intended to be used in initializing an object instance.

Parameters:

  • hashed_args (Hash) —

    A hash that should contain at least all the required keys and valid values, according to the arg_specs passed in. Nonrequired keys can be given as well, but if they are not then a default value is assigned (again, according to arg_specs passed in).

  • arg_specs (Hash) (defaults to: find_arg_specs) —

    A hash of ArgSpec objects. An ArgSpec object details what to expect from the hashed argument with a matching same key.

  • assign_args (true/false) (defaults to: true) —

    If true, the hashed args will be assigned to instance variables. If false, the hashed args will still be checked, but not assigned.



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# File 'lib/hashmake/hash_makeable.rb', line 34

def hash_make hashed_args, arg_specs = find_arg_specs, assign_args = true
  arg_specs.each do |key, arg_spec|
    if hashed_args.has_key?(key)
      val = hashed_args[key]
    else
      if arg_spec.reqd
        raise ArgumentError, "hashed_args does not have required key #{key}"
      else
        if arg_spec.default.is_a?(Proc) && arg_spec.type != Proc
          val = arg_spec.default.call
        else
          val = arg_spec.default
        end
      end
    end
    
    arg_spec.validate_value val
    
    if assign_args
      self.instance_variable_set("@#{key.to_s}".to_sym, val)
    end
  end
end