Class: RuboCop::AST::NodePattern::Compiler::Binding

Inherits:
Object
  • Object
show all
Defined in:
lib/rubocop/ast/node_pattern/compiler/binding.rb

Overview

Holds the list of bound variable names

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Binding

Returns a new instance of Binding.



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# File 'lib/rubocop/ast/node_pattern/compiler/binding.rb', line 9

def initialize
  @bound = {}
end

Instance Method Details

#bind(name) ⇒ String

Yields the first time a given name is bound

Returns:

  • (String) —

    bound variable name



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# File 'lib/rubocop/ast/node_pattern/compiler/binding.rb', line 16

def bind(name)
  var = @bound.fetch(name) do
    yield n = @bound[name] = "unify_#{name.gsub('-', '__')}"
    n
  end

  if var == :forbidden_unification
    raise Invalid, "Wildcard #{name} was first seen in a subset of a " \
                   "union and can't be used outside that union"
  end
  var
end

#union_bind(enum) ⇒ Object

rubocop:disable Metrics/MethodLength, Metrics/AbcSize



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# File 'lib/rubocop/ast/node_pattern/compiler/binding.rb', line 30

def union_bind(enum)
  # We need to reset @bound before each branch is processed.
  # Moreover we need to keep track of newly encountered wildcards.
  # Var `newly_bound_intersection` will hold those that are encountered
  # in all branches; these are not a problem.
  # Var `partially_bound` will hold those encountered in only a subset
  # of the branches; these can't be used outside of the union.

  return to_enum __method__, enum unless block_given?

  newly_bound_intersection = nil
  partially_bound = []
  bound_before = @bound.dup

  result = enum.each do |e|
    @bound = bound_before.dup if newly_bound_intersection
    yield e
    newly_bound = @bound.keys - bound_before.keys
    if newly_bound_intersection.nil?
      # First iteration
      newly_bound_intersection = newly_bound
    else
      union = newly_bound_intersection | newly_bound
      newly_bound_intersection &= newly_bound
      partially_bound |= union - newly_bound_intersection
    end
  end

  # At this point, all members of `newly_bound_intersection` can be used
  # for unification outside of the union, but partially_bound may not

  forbid(partially_bound)

  result
end