Numeric Literal Syntax

Dylan Enhancement Proposal (DEP) 11 extends the literal syntax for integers and floats to allow _ (underscore) between any two consecutive digits, to provide better readability for very large constants. This includes binary, octal, decimal, and hexadecimal literals.

Examples of valid numeric literals include:

1_000_000
-4_000_000
2.000_002
3_000.000_123
4.0e1_000
#xdead_beef
#b1111_0000

and also:

1_2_3_4_5_6_7  // valid but not recommended

Examples of uses of underscore that are not allowed include:

1__2
_123
-123_
1_.23
1._23
1.23_
#x_feed
#o777_

See DEP 11 for details.