lib/regexp_parser/syntax/version_lookup.rb
module Regexp::Syntax
VERSION_FORMAT = '\Aruby/\d+\.\d+(\.\d+)?\z'
VERSION_REGEXP = /#{VERSION_FORMAT}/
VERSION_CONST_REGEXP = /\AV\d+_\d+(?:_\d+)?\z/
class InvalidVersionNameError < Regexp::Syntax::SyntaxError
def initialize(name)
super "Invalid version name '#{name}'. Expected format is '#{VERSION_FORMAT}'"
end
end
class UnknownSyntaxNameError < Regexp::Syntax::SyntaxError
def initialize(name)
super "Unknown syntax name '#{name}'."
end
end
module_function
# Returns the syntax specification class for the given syntax
# version name. The special names 'any' and '*' return Syntax::Any.
def for(name)
(@alias_map ||= {})[name] ||= version_class(name)
end
def new(name)
warn 'Regexp::Syntax.new is deprecated in favor of Regexp::Syntax.for. '\
'It does not return distinct instances and will be removed in v3.0.0.'
self.for(name)
end
def supported?(name)
name =~ VERSION_REGEXP && comparable(name) >= comparable('1.8.6')
end
def version_class(version)
return Regexp::Syntax::Any if ['*', 'any'].include?(version.to_s)
version =~ VERSION_REGEXP || raise(InvalidVersionNameError, version)
version_const_name = "V#{version.to_s.scan(/\d+/).join('_')}"
const_get(version_const_name) || raise(UnknownSyntaxNameError, version)
end
def const_missing(const_name)
if const_name =~ VERSION_CONST_REGEXP
return fallback_version_class(const_name)
end
super
end
def fallback_version_class(version)
sorted = (specified_versions + [version]).sort_by { |ver| comparable(ver) }
index = sorted.index(version)
index > 0 && const_get(sorted[index - 1])
end
def specified_versions
constants.select { |const_name| const_name =~ VERSION_CONST_REGEXP }
end
def comparable(name)
# add .99 to treat versions without a patch value as latest patch version
Gem::Version.new((name.to_s.scan(/\d+/) << 99).join('.'))
end
end