Class: YamlExporter::Builder

Inherits:
Object
  • Object
show all
Defined in:
lib/yaml_exporter/builder.rb

Overview

Evaluates a yaml_structure do ... end block via instance_eval and emits a Structure. All declaration-time argument validation happens here (or inside the constructors of the Node classes it delegates to).

Accepts either a class or a callable that resolves to a class. The callable form lets node constructors defer AR reflection lookups until the inner block actually references the class (it doesn't, for attribute-only blocks) — this matters for anonymous ActiveRecord classes.

Instance Method Summary collapse

Constructor Details

#initialize(klass, &block) ⇒ Builder

Returns a new instance of Builder.



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# File 'lib/yaml_exporter/builder.rb', line 14

def initialize(klass, &block)
  @klass_resolver = klass.respond_to?(:call) ? klass : -> { klass }
  @nodes = []
  instance_eval(&block) if block
end

Instance Method Details

#attributes(*names) ⇒ Object

---- DSL ----------------------------------------------------------



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# File 'lib/yaml_exporter/builder.rb', line 26

def attributes(*names)
  names.each { |n| @nodes << Nodes::Attribute.new(name: n, owner_class: @klass_resolver) }
end

#build ⇒ Object 



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# File 'lib/yaml_exporter/builder.rb', line 20

def build
  Structure.new(klass: @klass_resolver, nodes: @nodes.freeze)
end

#many(name, find_by: nil, through: nil, positioned_by: nil, of: nil, &block) ⇒ Object 



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# File 'lib/yaml_exporter/builder.rb', line 52

def many(name, find_by: nil, through: nil, positioned_by: nil, of: nil, &block)
  if of && !find_by
    raise ArgumentError,
          "`many #{name.inspect}`: of: requires find_by:."
  end
  if of && block
    raise ArgumentError,
          "`many #{name.inspect}`: of: cannot combine with a block — of: only applies to " \
          'reference lists (no block).'
  end

  if through
    unless find_by
      raise ArgumentError,
            "`many #{name.inspect}`: through: requires find_by: to resolve the target."
    end
    # A block is optional: with one, its attributes describe the join row;
    # without one, the association is a bare reference list (and
    # positioned_by:, when given, derives the join's position column from
    # the YAML order). The join row itself is always managed by the DSL.
    @nodes << Nodes::ManyThrough.new(
      name: name, owner_class: klass, through: through, find_by: find_by,
      positioned_by: positioned_by, of: of, &block
    )
  elsif positioned_by && !block
    raise ArgumentError,
          "`many #{name.inspect}`: positioned_by: requires a block — the column lives on the owned record."
  elsif block && find_by
    @nodes << Nodes::ManyFindBy.new(
      name: name, owner_class: klass, find_by: find_by,
      positioned_by: positioned_by, &block
    )
  elsif block
    @nodes << Nodes::ManyPositional.new(
      name: name, owner_class: klass, positioned_by: positioned_by, &block
    )
  elsif find_by
    @nodes << Nodes::ManyReference.new(name: name, owner_class: klass, find_by: find_by, of: of)
  else
    raise ArgumentError,
          "`many #{name.inspect}`: pass either find_by: (reference list), a block (owned), " \
          'or both / through: + find_by: + block.'
  end
end

#one(name, find_by: nil, of: nil, &block) ⇒ Object 



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# File 'lib/yaml_exporter/builder.rb', line 30

def one(name, find_by: nil, of: nil, &block)
  if block && find_by
    raise ArgumentError,
          "`one #{name.inspect}`: cannot combine a block (owned) with find_by: (reference). Pick one."
  end
  if of && !find_by
    raise ArgumentError,
          "`one #{name.inspect}`: of: requires find_by:."
  end

  if block
    @nodes << Nodes::OneOwned.new(name: name, owner_class: klass, &block)
  elsif find_by && of
    @nodes << Nodes::OneReferenceOf.new(name: name, owner_class: klass, find_by: find_by, of: of)
  elsif find_by
    @nodes << Nodes::OneReference.new(name: name, owner_class: klass, find_by: find_by)
  else
    raise ArgumentError,
          "`one #{name.inspect}`: must pass either find_by: (reference) or a block (owned)."
  end
end