abstract type AtMostInf end                     # 0

multiplier_super = "Inf"
magnitude_ = ""
for magnitude in reverse(['n', 'u', 'm', ' ', 'K', 'M', 'G', 'T', 'P', 'E'])
    for multiplier in reverse([1, 2, 4, 8, 16, 32, 64, 128, 256, 512])
        magnitude_super = multiplier == 512 ? magnitude_ : magnitude   
        code = "abstract type AtMost" * string(multiplier) * magnitude * " <: AtMost" * string(multiplier_super) * magnitude_super * " end"        
        eval(Meta.parse(code)); println(code)
        multiplier_super = multiplier
    end
    magnitude_ = magnitude
end

abstract type AtMost0 <: AtMost1n end

abstract type AtMostInf end                     # 0
let mul_super = "Inf" ,
    mag_ = "" ;
    for mag in reverse(['n', 'u', 'm', ' ', 'K', 'M', 'G', 'T', 'P', 'E'])
        for mul in reverse([1, 2, 4, 8, 16, 32, 64, 128, 256, 512])
            mag_super = mul==512 ? mag_ : mag
            nm1 = Symbol("AtMost" * string(mul) * mag)
            nm2 = Symbol("AtMost" * string(mul_super) * mag_super)
            @eval abstract type $nm1 <: $nm2 end
            mul_super = mul
        end
        mag_ = mag
    end
end
abstract type AtMost0 <: AtMost1n end

using Test
@test AtMost16G |> supertype == AtMost32G
@test AtMost128u |> supertype == AtMost256u
@test AtMost4P |> supertype == AtMost8P
@test AtMost256M |> supertype == AtMost512M