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unless ([[]].flatten(1) rescue false)
require 'backports/tools/alias_method_chain'
require 'backports/tools/arguments'
class Array
# Recursively flatten any contained Arrays into an one-dimensional result.
# Adapted from rubinius'
def flatten_with_optional_argument(level=-1)
dup.flatten!(level) || self
end
# Flattens self in place as #flatten. If no changes are
# made, returns nil, otherwise self.
# Adapted from rubinius'
def flatten_with_optional_argument!(level=-1)
level = Backports.coerce_to_int(level)
return flatten_without_optional_argument! if level < 0
out = []
ret = recursively_flatten_finite(self, out, level)
replace(out) if ret
ret
end
Backports.alias_method_chain self, :flatten, :optional_argument
Backports.alias_method_chain self, :flatten!, :optional_argument
# Helper to recurse through flattening
# Adapted from rubinius'; recursion guards are not needed because level is finite
def recursively_flatten_finite(array, out, level)
ret = nil
if level <= 0
out.concat(array)
else
array.each do |o|
if ary = Backports.is_array?(o)
recursively_flatten_finite(ary, out, level - 1)
ret = self
else
out << o
end
end
end
ret
end
private :recursively_flatten_finite
end
end
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