distraction.party/lib/pleroma/emoji/combinations.ex

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# Pleroma: A lightweight social networking server
# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.Emoji.Combinations do
# FE0F is the emoji variation sequence. It is used for fully-qualifying
# emoji, and that includes emoji combinations.
# This code generates combinations per emoji: for each FE0F, all possible
# combinations of the character being removed or staying will be generated.
# This is made as an attempt to find all partially-qualified and unqualified
# versions of a fully-qualified emoji.
# I have found *no cases* for which this would be a problem, after browsing
# the entire emoji list in emoji-test.txt. This is safe, and, sadly, most
# likely sane too.
defp qualification_combinations(codepoints) do
qualification_combinations([[]], codepoints)
end
defp qualification_combinations(acc, []), do: acc
defp qualification_combinations(acc, ["\uFE0F" | tail]) do
acc
|> Enum.flat_map(fn x -> [x, x ++ ["\uFE0F"]] end)
|> qualification_combinations(tail)
end
defp qualification_combinations(acc, [codepoint | tail]) do
acc
|> Enum.map(&Kernel.++(&1, [codepoint]))
|> qualification_combinations(tail)
end
def variate_emoji_qualification(emoji) when is_binary(emoji) do
emoji
|> String.codepoints()
|> qualification_combinations()
|> Enum.map(&List.to_string/1)
end
def variate_emoji_qualification(emoji) when is_list(emoji) do
emoji
|> Enum.map(fn emoji -> {emoji, variate_emoji_qualification(emoji)} end)
end
end