local fmt = require "fmt"
require "uchar"

-- Returns squeezed string, original and new lengths in
-- unicode code points (not normalized).
local function squeeze(s, ch)
    local c = uchar.of(s)
    local c2 = uchar.of(ch)
    local le = c:len()
    if le < 2 then return s, le, le end
    for i = le - 1, 1, -1 do
        if c:get(i) == c2:get(1) and c:get(i) == c:get(i + 1) then c:remove(i) end
    end
    return c:tostring(), le, c:len()
end

local strings = {
    "",
    "\"If I were two-faced, would I be wearing this one?\" --- Abraham Lincoln ",
    "..1111111111111111111111111111111111111111111111111111111111111117777888",
    "I never give 'em hell, I just tell the truth, and they think it's hell. ",
    "                                                   ---  Harry S Truman  ",
    "The better the 4-wheel drive, the further you'll be from help when ya get stuck!",
    "headmistressship",
    "aardvark",
    "😍😀🙌💃😍😍😍🙌"
}

local chars = { {" "}, {"-"}, {"7"}, {"."}, {" ", "-", "r"}, {"e"}, {"s"}, {"a"}, {"😍"} }

for i, s in strings do
    for chars[i] as ch do
        local cc, le, lcc = squeeze(s, ch)
        print($"Specified character = '{ch}'")
        fmt.print("original : length = %2d, string = «««%s»»»", le, s)
        fmt.print("squeezed : length = %2d, string = «««%s»»»\n", lcc, cc)
    end
end