Module: Weft::DSL::Containers

Included in:
Component, Page
Defined in:
lib/weft/dsl/containers.rb

Overview

Mixin for the adds_children_to :@ivar macro — generates the standard Arbre container override that redirects user-block children into a nested element while letting structural children (added during build) pass through to the wrapper.

Mixed into both Weft::Component and Weft::Page by default. Usable on any class that inherits from Arbre::Component.

class Card < Weft::Component
adds_children_to :@body

def build(attributes = {})
  super
  h2 "Header"            # structural — goes to wrapper
  @body = div(class: "card-body")
end
end

The :@body form (with the leading @) is required — a pedagogical cue that the macro depends on the user assigning the ivar somewhere in build. If build returns without setting the ivar and a child is then added, the macro raises with a pointed error message.

Defined Under Namespace

Modules: ClassMethods

Class Method Summary collapse

Class Method Details

.behavior_for(ivar) ⇒ Object

Build the prepended Module that implements both the build wrap (to detect "build returned without assigning the ivar") and the add_child redirect. Each call returns a fresh anonymous module — declaring the macro on multiple classes is safe.



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# File 'lib/weft/dsl/containers.rb', line 53

def self.behavior_for(ivar)
  Module.new do
    define_method(:build) do |*args, **kwargs|
      super(*args, **kwargs)
      @_weft_container_built = true
    end

    define_method(:add_child) do |child|
      target = instance_variable_defined?(ivar) ? instance_variable_get(ivar) : nil
      if target
        target << child
      elsif @_weft_container_built
        raise Weft::MissingContainerIvar,
              "#{self.class} declared `adds_children_to #{ivar.inspect}` " \
              "but never assigned #{ivar} in build " \
              "(e.g., #{ivar} = div(class: 'body') inside build)"
      else
        super(child)
      end
    end
  end
end

.included(base) ⇒ Object 



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# File 'lib/weft/dsl/containers.rb', line 28

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