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From: Antoon Pardon <antoon.pardon@rece.vub.ac.be>
Newsgroups: comp.lang.python
Subject: Re: What is a function parameter =[] for?
Date: Wed, 25 Nov 2015 10:56:27 +0100
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Xref: csiph.com comp.lang.python:99430

Op 25-11-15 om 01:36 schreef Steven D'Aprano:
> On Wed, 25 Nov 2015 08:25 am, Antoon Pardon wrote:
>
>> The point is that a
>> tuple can just be loaded as a constant without needing something extra.
>
> How would one load this tuple as a constant?
>
> (myfile.read(), "%.5f" % sin(x or y))

Picking nits again. That respons was done in a context fo what I called
literals. Do you expect me to summarize the context in each response?

> The point is that *in general*, tuple so-called "literals" (what the docs
> call displays) cannot be loaded as constants. If, and only if, the tuple
> contains nothing but immutable constants e.g.
>
> (1, 2.0, None, "spam")
>
> then a sufficiently smart compiler may be able to treat that specific tuple
> as a constant/literal. But that's a special case, and cannot be generalised
> to all tuple displays.
>
> All tuple so-called "literals" e.g. (), (1, 2), (x, y, z) etc. are
> fundamentally expressions that *may* have to be built at runtime. Hence the
> word "literal" is inappropriate.

Literals are constants. So (x, y, z) is not a literal. This is what wikipedia
says: 

    In computer science, a literal is a notation for representing a fixed
    value in source code.

Since (x, y, z) is not a fixed value, it is not a literal.

-- 
Antoon.