[Python-Dev] Symmetry arguments for API expansion

[Serhiy Storchaka]

13.03.18 10:35, Larry Hastings пише:
> On 03/12/2018 08:41 PM, Guido van Rossum wrote:
>> If you force me to choose between allowing hex(3.14) or 42.hex() I'll 
>> choose the latter
> 
> I assume you meant (42).hex() here.  If you're also interested in 
> changing the language to permit 42.hex(), well, color me shocked :D
> 
> (For those who haven't seen this before: it's a well-known gotcha. When 
> Python's grammar sees "42.hex()", it thinks "42." is the start of a 
> floating-point constant.  But "42.hex" isn't a valid floating-point 
> constant, so it throws a SyntaxError.)

"42." is a valid floating-point constant. But a floating-point constant 
followed by an identifier is an invalid syntax. This is the same error 
as in "42. hex" and "42 hex".