Class: ROM::Relation::Curried

Inherits:
Object
  • Object
show all
Extended by:
Initializer
Includes:
Pipeline, Materializable
Defined in:
lib/rom/relation/curried.rb

Overview

Curried relation is a special relation proxy used by auto-curry mechanism.

When a relation view method is called without all arguments, a curried proxy is returned that can be fully applied later on.

Curried relations are typically used for relation composition

Constant Summary collapse

WRAPS = 
[Relation, Graph, Wrap, Composite].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Initializer

extended

Methods included from Pipeline

#map_with

Methods included from Pipeline::Operator

#>>

Methods included from Materializable

#each, #first, #one, #one!

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(meth) ⇒ Object (private)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



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# File 'lib/rom/relation/curried.rb', line 110

def method_missing(meth, ...)
  if relation.respond_to?(meth)
    response = relation.__send__(meth, ...)

    super if response.is_a?(self.class)

    if WRAPS.any? { |klass| response.is_a?(klass) }
      __new__(response)
    else
      response
    end
  else
    super
  end
end

Instance Attribute Details

#arity ⇒ Integer (readonly)

Returns View’s arity.

Returns:

  • (Integer) —

    View’s arity



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# File 'lib/rom/relation/curried.rb', line 43

option :arity, type: Types::Strict::Integer

#curry_args ⇒ Array (readonly)

Returns Arguments that will be passed to curried view.

Returns:

  • (Array) —

    Arguments that will be passed to curried view



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# File 'lib/rom/relation/curried.rb', line 47

option :curry_args, default: -> { EMPTY_ARRAY }

#relation ⇒ Relation (readonly)

Returns The source relation that is curried.

Returns:

  • (Relation) —

    The source relation that is curried



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# File 'lib/rom/relation/curried.rb', line 35

param :relation

#view ⇒ Symbol (readonly)

Returns The name of relation’s view method.

Returns:

  • (Symbol) —

    The name of relation’s view method



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# File 'lib/rom/relation/curried.rb', line 39

option :view, type: Types::Strict::Symbol

Instance Method Details

#call(*args) ⇒ Loaded, Curried Also known as: []

Load relation if args match the arity

Returns:



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# File 'lib/rom/relation/curried.rb', line 54

def call(*args)
  all_args = curry_args + args

  if all_args.empty?
    raise ArgumentError,
          "curried #{relation.class}##{view} relation was called without any arguments"
  end

  if args.empty?
    self
  elsif arity == all_args.size
    Loaded.new(relation.__send__(view, *all_args))
  else
    __new__(relation, curry_args: all_args)
  end
end

#curried? ⇒ true

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Return if this lazy relation is curried

Returns:

  • (true) 


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# File 'lib/rom/relation/curried.rb', line 92

def curried? = true

#respond_to_missing?(name, include_private = false) ⇒ Boolean

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns:

  • (Boolean) 


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# File 'lib/rom/relation/curried.rb', line 95

def respond_to_missing?(name, include_private = false)
  super || relation.respond_to?(name, include_private)
end

#to_a ⇒ Object Also known as: to_ary

Relations are coercible to an array but a curried relation cannot be coerced When something tries to do this, an exception will be raised

Raises:

  • ArgumentError



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# File 'lib/rom/relation/curried.rb', line 78

def to_a
  raise(
    ArgumentError,
    "#{relation.class}##{view} arity is #{arity} " \
    "(#{curry_args.size} args given)"
  )
end