[Python-ideas] Hexadecimal floating literals

[David Mertz]

-1

Writing a floating point literal requires A LOT more knowledge than writing
a hex integer.

What is the bit length of floats on your specific Python compile? What
happens if you specify more or less precision than actually available.
Where is the underflow to subnormal numbers? What is the bit representation
of information? Nan? -0 vs +0?

There are people who know this and need to know this. But float.fromhex()
is already available to them. A literal is an attractive nuisance for
people who almost-but-not-quite understand IEEE-854. I.e. those people who
named neither Tim Peters nor Mike Cowlishaw.

On Sep 21, 2017 9:48 AM, "Lucas Wiman" <lucas.wiman at gmail.com> wrote:

On Thu, Sep 21, 2017 at 8:23 AM, Victor Stinner <victor.stinner at gmail.com>
wrote:

> While I was first in favor of extending the Python syntax, I changed
> my mind. Float constants written in hexadecimal is a (very?) rare use
> case, and there is already float.fromhex() available.
>
> A new syntax is something more to learn when you learn Python. Is it
> worth it? I don't think so. Very few people need to write hexadecimal
> constants in their code.
>

It is inconsistent that you can write hexadecimal integers but not floating
point numbers. Consistency in syntax is fewer things to learn, not more.
That said, I agree it's a rare use case, so it probably doesn't matter much
either way.

- Lucas

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