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Contents
# frozen_string_literal: true
module RBS
class Substitution
attr_reader :mapping
attr_accessor :instance_type
def empty?
mapping.empty? && instance_type.nil?
end
def initialize()
@mapping = {}
end
def add(from:, to:)
mapping[from] = to
end
def self.build(variables, types, instance_type: nil, &block)
unless variables.size == types.size
raise "Broken substitution: variables=#{variables}, types=#{types}"
end
mapping = variables.zip(types).to_h
self.new.tap do |subst|
mapping.each do |v, t|
type = block_given? ? yield(t) : t
subst.add(from: v, to: type)
end
subst.instance_type = instance_type
end
end
def apply(ty)
case ty
when Types::Variable
# @type var ty: Types::Variable
mapping[ty.name] || ty
when Types::Bases::Instance
if t = instance_type
t
else
ty
end
else
ty
end
end
alias [] apply
def without(*vars)
Substitution.new.tap do |subst|
subst.mapping.merge!(mapping)
vars.each do |var|
subst.mapping.delete(var)
end
subst.instance_type = self.instance_type
end
end
def +(other)
return self if other.empty?
return other if self.empty?
Substitution.new.tap do |subst|
subst.mapping.merge!(mapping)
other.mapping.each do |var, type|
if mapping.key?(var)
subst.add(from: var, to: self[type])
else
subst.add(from: var, to: type)
end
end
end
end
end
end
Version data entries
46 entries across 46 versions & 2 rubygems