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Contents
# frozen_string_literal: true
module SyntaxTree
module YARV
# This represents every local variable associated with an instruction
# sequence. There are two kinds of locals: plain locals that are what you
# expect, and block proxy locals, which represent local variables
# associated with blocks that were passed into the current instruction
# sequence.
class LocalTable
# A local representing a block passed into the current instruction
# sequence.
class BlockLocal
attr_reader :name
def initialize(name)
@name = name
end
end
# A regular local variable.
class PlainLocal
attr_reader :name
def initialize(name)
@name = name
end
end
# The result of looking up a local variable in the current local table.
class Lookup
attr_reader :local, :index, :level
def initialize(local, index, level)
@local = local
@index = index
@level = level
end
end
attr_reader :locals
def initialize
@locals = []
end
def empty?
locals.empty?
end
def find(name, level = 0)
index = locals.index { |local| local.name == name }
Lookup.new(locals[index], index, level) if index
end
def has?(name)
locals.any? { |local| local.name == name }
end
def names
locals.map(&:name)
end
def name_at(index)
locals[index].name
end
def size
locals.length
end
# Add a BlockLocal to the local table.
def block(name)
locals << BlockLocal.new(name) unless has?(name)
end
# Add a PlainLocal to the local table.
def plain(name)
locals << PlainLocal.new(name) unless has?(name)
end
# This is the offset from the top of the stack where this local variable
# lives.
def offset(index)
size - (index - 3) - 1
end
end
end
end
Version data entries
9 entries across 9 versions & 1 rubygems