The hope is that these could be added either built-in to the language or simply defined by JavaScript code, without using transpilers/tools. Part of the picture of generalizing built-in syntax is ...

So C# has decimals, numeric real literals which are stored as doubles unless you suffix it with the type (M or m for decimal)... I don't quite understand the significance of this. Also of course ...

A set of contiguous characters that make up a numeric value in the source code of a program. The values may be expressed in decimal, hexadecimal or octal notation. Contrast with string literal. THIS ...

Since Julia allows numeric literals to be [juxtaposed with identifiers as coefficients] (@ref man-numeric-literal-coefficients), this binding suffices to provide convenient syntax for complex numbers, ...