# Is `self` a well-formed Integer (i.e. parsable via `to_i`)
	#
	#     assert "123".is_int
	#     assert "0b1011".is_int
	#     assert "-34".is_int
	#     assert "+45".is_int
	#     assert not "0x_".is_int
	#     assert not "0xGE".is_int
	#     assert not "".is_int
	#     assert not "Not an Int".is_int
	#     assert not "-".is_int
	fun is_int: Bool do
		if byte_length == 0 then return false
		var s = remove_all('_')
		var pos = 0
		var len = s.length
		while pos < len and (s[pos] == '-' or s[pos] == '+') do
			pos += 1
		end
		s = s.substring_from(pos)
		var rets = s.strip_numhead
		if rets == "" then return false
		var hd = get_numhead
		if hd == "0x" or hd == "0X" then return rets.is_hex
		if hd == "0b" or hd == "0B" then return rets.is_bin
		if hd == "0o" or hd == "0O" then return rets.is_oct
		return rets.is_dec
	end