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module StringDirection
# String direction detector
class Detector
# Array of initialized strategies used, in order, to try to detect the direction of a string
#
# @return [Array]
attr_accessor :strategies
# Initialize strategies from given arguments. If no strategies are given, they are taken from the value of {StringDirection::Configuration#default_strategies}
#
# @raise [ArgumentError] if strategy class is not found. For example, for an strategy `:marks` a class `StringDirection::MarksStrategy` is expected
def initialize(*strategies)
strategies = StringDirection.configuration.default_strategies if strategies.empty?
initialize_strategies(strategies)
end
# Tries to detect and return the direction of a string. It returns `ltr` if the string is left-to-right, `rtl` if it is right-to-left, `bidi` if it is bidirectional or `nil` if it can't detect the direction. It iterates through {#strategies} until one of them successes.
#
# @param string [String] The string to inspect
# @return [String, nil]
def direction(string)
direction = nil
strategies.each do |strategy|
direction = strategy.run(string)
break if direction
end
direction
end
# Returns whether string is left-to-right or not
#
# @param string [String] The string to inspect
# @return [Boolean]
def ltr?(string)
direction(string) == ltr
end
# Returns whether string is right-to-left or not
#
# @param string [String] The string to inspect
# @return [Boolean]
def rtl?(string)
direction(string) == rtl
end
# Returns whether string is bidirectional or not
#
# @param string [String] The string to inspect
# @return [Boolean]
def bidi?(string)
direction(string) == bidi
end
private
def initialize_strategies(strategies)
self.strategies = strategies.map do |strategy|
begin
name = infer_strategy_class_name(strategy)
Kernel.const_get(name).new
rescue NameError
raise ArgumentError, "Can't find '#{name}' strategy"
end
end
end
def infer_strategy_class_name(strategy)
base_name = strategy.to_s.split('_').map(&:capitalize).join
"StringDirection::#{base_name}Strategy"
end
def ltr
StringDirection::LTR
end
def rtl
StringDirection::RTL
end
def bidi
StringDirection::BIDI
end
end
end
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