require "io2"

-- Split a string using one or more whitespace or comma characters as the separator.
local function split2(s)
    -- Replace all commas with spaces.
    s = s:replace(",", " ")
    -- Split on spaces and remove empty entries.
    return s:split(" "):filter(|e| -> #e > 0):reorder()
end

local function spark(s0)
    local ss = split2(s0)
    local n = #ss
    local vs = table.create(n)
    local min = math.huge
    local max = -min
    for i, s in ss do
        local v = tonumber(s)
        if math.isnan(v) or v == math.huge or v == -math.huge then
            error("Infinities and NaN not supported.")
        end
        if v < min then min = v end
        if v > max then max = v end
        vs[i] = v
    end
    local sp
    if min == max then
        sp = string.rep("▄", n)
    else
        local rs = table.create(n)
        local f = 8 / (max - min)
        for j, v in vs do
            local i = math.floor(f * (v - min))
            if i > 7 then i = 7 end
            rs[j] = utf8.char(0x2581 + i)
        end
        sp = rs:concat()
    end
    return sp, n, min, max
end

while true do
    local numbers = io.readStr("Numbers please separated by spaces/commas or q to quit:\n", 1)
    if !numbers then break end
    local s, n, min, max = spark(numbers)
    if n == 1 then
        print($"1 value = {min}")
    else
        print($"{n} values.  Min: {min} Max: {max}")
    end
    print(s)
    print()
end