Class: Hecks::Bluebook::Reference

Inherits:
Object
  • Object
show all
Defined in:
lib/hecks/bluebook/reference.rb

Overview

An attribute that points at another aggregate's head.

This used to be the STRING "Reference<Customer>", minted by AggregateBuilder#reference_to and CommandBuilder#cross_reference from a real constant that had just been handed in, and then parsed back apart by a regex in the command interpreter, by string equality in the read-model interpreter and the SQLite adapter, and by delete_prefix in the bluebook builder. Five readers of a spelling one writer invented.

It holds the TARGET instead, and answers resolve with the target's Aggregate. Resolution is LAZY and deliberately so: reference_to Customer may name an aggregate declared lower in the file — banking's Account points at Customer and survives only because Customer happens to be written above — so the edge cannot be resolved at declaration time. It resolves through the chapter's own IR (Bluebook#aggregate), which is scoped by construction : the lookup cannot walk anywhere but this chapter's declared heads, so a same-named aggregate in another loaded domain is unreachable rather than defended against.

to_s still spells "Reference<Customer>", because Attribute#to_h is part of the pinned byte-for-byte export contract. IR objects in the graph, strings in the export.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(target_name) ⇒ Reference

Returns a new instance of Reference.



32
33
34
 
# File 'lib/hecks/bluebook/reference.rb', line 32

def initialize(target_name)
  @target_name = Naming.demodulise(target_name).to_s
end

Instance Attribute Details

#declared_in ⇒ Object

The Aggregate whose declaration carries this reference — the way up to the chapter, stamped once every sibling has been read.



30
31
32
 
# File 'lib/hecks/bluebook/reference.rb', line 30

def declared_in
  @declared_in
end

#target_name ⇒ Object (readonly)

Returns the value of attribute target_name.



26
27
28
 
# File 'lib/hecks/bluebook/reference.rb', line 26

def target_name
  @target_name
end

Instance Method Details

#==(other) ⇒ Object Also known as: eql?

VALUE EQUALITY, not identity — without this, two references to the SAME target, parsed from two SEPARATE bluebook reads (era N's own boot and a held era's own shadow reconstruction, coverage_check.rb's own comparison), are different objects and compare unequal by Ruby's default ==. EraGuard::ShapeDiff #diff_type's held_type != current_type check then reads as true for EVERY reference_to attribute on EVERY mint, regardless of whether the reference actually changed — a real refusal for attributes nothing about. declared_in (which aggregate carries this reference) is deliberately excluded: the same reference attribute exists once, but its held_type/current_type come from separately-parsed bluebooks with structurally different (if same-shaped) owning aggregates, and declared_in is a cross-reference for resolve, not part of what this attribute itself IS.



69
 
# File 'lib/hecks/bluebook/reference.rb', line 69

def ==(other) = other.is_a?(Reference) && target_name == other.target_name

#hash ⇒ Object 



71
 
# File 'lib/hecks/bluebook/reference.rb', line 71

def hash = [self.class, target_name].hash

#inspect ⇒ Object 



52
 
# File 'lib/hecks/bluebook/reference.rb', line 52

def inspect = "#<Reference #{@target_name}>"

#resolve ⇒ Object

The Aggregate this points at, or nil when the target belongs to ANOTHER domain — a cross-domain target may legitimately not be loaded, the same reading across policies get.



39
40
41
42
43
44
45
46
47
48
 
# File 'lib/hecks/bluebook/reference.rb', line 39

def resolve
  unless declared_in
    raise DSL::Malformed,
          "#{self} cannot say which aggregate declares it, so it cannot " \
          "resolve — a reference that resolves to nothing is checked " \
          "against nothing"
  end

  declared_in.hecks_owner&.aggregate(@target_name)
end

#to_s ⇒ Object

The IR spelling, the one the export carries.



51
 
# File 'lib/hecks/bluebook/reference.rb', line 51

def to_s = "Reference<#{@target_name}>"