[issue23231] Fix codecs.iterencode/decode() by allowing data parameter to be omitted

[Serhiy Storchaka]

Serhiy Storchaka added the comment:

The patch changes public interface. This breaks compatibility with third-party codecs implementing it.

We have found other solution to iterencode/iterdecode problem. For example we can buffer iterated values and encode with one step delay:

    prev = sentinel = object()
    for input in iterator:
        if prev is not sentinel:
            output = encoder.encode(prev)
            if output:
                yield output
        prev = input
    if prev is not sentinel:
        output = encoder.encode(prev, True)
        if output:
            yield output

Or remember the previous value and use it to calculate the empty value at the end (works only if input type supports slicing):

    prev = sentinel = object()
    for input in iterator:
        output = encoder.encode(input)
        if output:
            yield output
        prev = input
    if prev is not sentinel:
        output = encoder.encode(prev[:0], True)
        if output:
            yield output

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nosy: +doerwalter, lemburg
versions: +Python 3.6 -Python 3.5

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<http://bugs.python.org/issue23231>
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