JISON: why in regexp used "." instead of \.?

Question

From example on http://zaach.github.io/jison/docs/#specifying-a-language

[0-9]+("."[0-9]+)?\b  return 'NUMBER';

why in this regexp used "." instead of \. ?

Answer 1

Because that's a Jison grammar tokenization rule not an exact regex.
In Jison a token is surrounded in ".

In the compiled rules you can see the rule converted to a regex:

["[0-9]+(?:\\.[0-9]+)?\\b", "return 'NUMBER';"],