bug#48678: [PATCH] lex floats with trailing dot and exponent correctly

[Eli Zaretskii]

> From: Mattias Engdegård <mattiase@acm.org>
> Date: Wed, 26 May 2021 18:56:43 +0200
> 
> Now Emacs has always treated numbers like 123. as integers rather than 
> floats, but
> (1) it's documented,
> (2) it's what Common Lisp does, and
> (3) it actually doesn't affect the numeric value most of the time.
> 
> (Common Lisp probably got this from Maclisp, the rationale being that a 
> trailing dot can be used to write integers in base 10 even when the current 
> input radix is set to something else, something that Emacs Lisp doesn't need.)
> 
> Obviously this doesn't apply to 1.e6 which any sane person agrees is the 
> float 1.0e+6 (including Common Lisp).
> 
> The attached patch fixes this bug.

Brace for massive breakage.