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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;color:#1F497D;mso-fareast-language:EN-US">Hello,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;color:#1F497D;mso-fareast-language:EN-US">You’re presumably doing something like ‘star = starcaller(f); star((“foo”, “bar”, “baz”))’ – how is it different from ‘f(*(“foo”, “bar”, “baz”))’ ? I don’t
see any difference…<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;color:#1F497D;mso-fareast-language:EN-US">-Emanuel<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="FR" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="FR" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Python-ideas [mailto:python-ideas-bounces+vgr255=live.ca@python.org]
<b>On Behalf Of </b>Daniel Spitz<br>
<b>Sent:</b> Thursday, July 21, 2016 10:07 AM<br>
<b>To:</b> python-ideas@python.org<br>
<b>Subject:</b> [Python-ideas] Addition to operator module: starcaller<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#212121">Hello,</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#212121"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#212121">I have run into a use case where I want to create a wrapper object that will star-unpack a sequence of arguments to pass to a function. Currently one way to
construct this is to create a function:<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#212121"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New";color:#212121">def starcaller(f):</span><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#212121"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New";color:#212121"> def wrapper(args):</span><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#212121"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New";color:#212121"> return f(*args)</span><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#212121"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New";color:#212121"> return wrapper</span><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#212121"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#212121"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#212121">Such a function feels simple enough, and specific enough to the language, that it would fit in well in the operator module of the standard library. We already
have a similar representation of this functionality in itertools.starmap.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#212121"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#212121">Whereas the nested function implementation above will produce unpickleable objects (due to the closure), a straightforward c implementation will produce pickleable
ones, making them useful for parallel applications.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#212121"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#212121">Thanks,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#212121">Dan Spitz<o:p></o:p></span></p>
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