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.



14
15
16
17
18
 
# 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 ----------------------------------------------------------



26
27
28
 
# 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 



20
21
22
 
# 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, &block) ⇒ Object 



52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
 
# File 'lib/yaml_exporter/builder.rb', line 52

def many(name, find_by: nil, through: nil, positioned_by: nil, &block)
  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, &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)
  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 



30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
 
# 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