Decimal Real Numbers

These numbers represent the full range of real numbers with
decimal point and optional exponent. Their binary representation in the system
memory is standardised by IEEE-754 as 64 bits long, and able to cover at least
the range from 10^{−308} to 10^{308}

Typically, the accuracy after the decimal point can go as deep as 16 digits.

The format is again an optional minus or plus character,
followed by one or more decimal numbers, followed by an optional decimal point
and more decimal numbers, after which an optional exponent character ‘**e**’ or ‘**E**’ should be followed again by a standard signed or unsigned decimal
number and optional decimal point part.

The Exponent part defines the number in standard scientific exponential format.

In summary the whole real number can be expressed as:

[**-**] **integer **[**.****fraction**] [**E **[**-**] **exponent **[**.****fraction**]]

Examples of several real numbers in Rittle: *-0.3 6.779
-2E11 9.03E-2.84*