[ python-Bugs-1084279 ] status of small floats in xml-rpc ?

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Bugs item #1084279, was opened at 2004-12-13 05:07
Message generated for change (Comment added) made by rhettinger
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Category: Python Library
Group: Python 2.4
Status: Open
Resolution: None
Priority: 5
Submitted By: Antoine Pitrou (pitrou)
>Assigned to: Martin v. Löwis (loewis)
Summary: status of small floats in xml-rpc ?

Initial Comment:
Hi,

I've been reading through the xmlrpclib.py code to see
that floats are marshalled the following way:

    def dump_double(self, value, write):
        write("<value><double>")
        write(repr(value))
        write("</double></value>\n")
    dispatch[FloatType] = dump_double

Using repr() means that small or big floats, for
example, will be output using the exponent notation:
>>> repr(2**-15)
'3.0517578125e-05'

Unfortunately, the XML-RPC specification does not allow
this notation:
"At this time, only decimal point notation is allowed,
a plus or a minus, followed by any number of numeric
characters, followed by a period and any number of
numeric characters. Whitespace is not allowed. The
range of allowable values is implementation-dependent,
is not specified."
(http://www.xmlrpc.com/spec)

Thus floats marshalled using xmlrpclib may not be
readable using other XML-RPC implementations.

(I don't have any concrete data about this though)


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>Comment By: Raymond Hettinger (rhettinger)
Date: 2004-12-13 07:40

Message:
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I loaded a recipe for a helper function that meets the spec:

http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/358361

Inserting and applying the helper function ought to be
backwards compatible (the new encoding is readable by
previous versions).

Martin, do you agree with approach and concur that it should
be backported?

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