Yes, in Squeak this behavior is obtained with the ExtendedNumberParser.
You can read these floats for example:

1.
1.e+30
.1
-.1e+30

Though, in Smalltalk source code, the SqNumberParser is used and you can't.

Nicolas

2011/8/12 Frank Shearar <frank.shearar at gmail.com>:
> Hi,
>
> While playing around, I've found that Number readFrom: '1.' returns
> 1.0 ... I'd expected a 1.
>
> Is this expected behaviour?
>
> frank
>
>