Sha256: 96ef65e5a7fac08125783264014926ab681e8bc64ed3e3fe9877e2bc55499f6d
Contents?: true
Size: 1.69 KB
Versions: 18
Compression:
Stored size: 1.69 KB
Contents
# frozen_string_literal: true
module Loxxy
module Ast
# Mix-in module that relies on meta-programming to add a method
# called `accept` to the host class (an AST node).
# That method fulfills the expected behavior of the `visitee` in
# the Visitor design pattern.
module ASTVisitee
# Convert the input string into a snake case string.
# Example: ClassExpr => class_expr
# @param aName [String] input name to convert
# @return [String] the name converted into snake case
def snake_case(aName)
converted = +''
down = false
aName.each_char do |ch|
lower = ch.downcase
if lower == ch
converted << ch
down = true
else
converted << '_' if down && converted[-1] != '_'
converted << lower
down = false
end
end
converted
end
# This method adds a method named `accept` that takes a visitor
# The visitor is expected to implement a method named:
# visit + class name (without the Lox prefix) in snake case
# Example: class name = LoxClassStmt => visit method = visit_class_stmt
def define_accept
return if instance_methods(false).include?(:accept)
base_name = name.split('::').last
name_suffix = snake_case(base_name).sub(/^lox/, '')
accept_body = <<-MTH_END
# Part of the 'visitee' role in Visitor design pattern.
# @param visitor [Ast::ASTVisitor] the visitor
def accept(aVisitor)
aVisitor.visit#{name_suffix}(self)
end
MTH_END
class_eval(accept_body)
end
end # module
end # module
end # module
Version data entries
18 entries across 18 versions & 1 rubygems