nimrod modules error

gistfile1.nim

# --- serialize.nim ---
import streams
#import archive    # works if I uncomment this line

proc `<<`*[TA,T] (a: TA, x: T):     TA
proc `>>`*[TA,T] (a: TA, x: var T): TA

proc save*[TA,T](a: TA, x: seq[T]): TA =
    discard a << len(x)
    for v in x:
        discard a << v
    return a

proc load*[TA,T](a: TA, x: var seq[T]): TA =
    var
        length: int
        v: T

    discard a >> length
    x = @[]
    for i in 0..length-1:
        discard a >> v
        x.add(v)
    return a

proc `<<`[TA,T] (a: TA, x: T): TA =
    save(a, x)

proc `>>`[TA,T] (a: TA, x: var T): TA =
    load(a, x)

# --- archive.nim ---
import streams

type
    TBinArchive* = object
        stream*:    PStringStream

proc reset*(a: TBinArchive): void =
    a.stream.setPosition(0)

# Save
proc save*(a: TBinArchive, x: int): TBinArchive =
    a.stream.write(x)
    return a

proc save*(a: TBinArchive, s: string): TBinArchive =
    save(a, len(s)).stream.write(s)
    return a

# Load
proc load*(a: TBinArchive, x: var int): TBinArchive =
    discard a.stream.readData(addr(x), sizeof(int))
    return a

proc load*(a: TBinArchive, s: var string): TBinArchive =
    var length: int
    s = load(a, length).stream.readStr(length)
    return a

# --- test.nim ---
import archive, serialize
import streams

when isMainModule:
    var a: TBinArchive = TBinArchive(stream: newStringStream())

    var lst: seq[int] = @[2,3,4,5]
    var f: float = 5.6
    discard a << "ABC" << 64 << lst

    reset(a)
    var s: string
    var i: int
    var lst2: seq[int]
    discard a >> s >> i >> lst2

    echo s, " ", i
    for v in lst2:
        echo v