/ token in function parameterlist

[tpourjalali]

So I'm learning python by just reading documentation after I decided that none of the books and courses out there are good enough. Here's the question in the funcdef documentation we have

funcdef ::= [decorators] "def" funcname "(" [parameter_list] ")" ["->" expression] ":" suite decorators ::= decorator+ decorator ::= "@" dotted_name ["(" [argument_list [","]] ")"] NEWLINE dotted_name ::= identifier ("." identifier)* parameter_list ::= defparameter ("," defparameter)* "," "/" ["," [parameter_list_no_posonly]] | parameter_list_no_posonly parameter_list_no_posonly ::= defparameter ("," defparameter)* ["," [parameter_list_starargs]] | parameter_list_starargs parameter_list_starargs ::= "*" [parameter] ("," defparameter)* ["," ["**" parameter [","]]] | "**" parameter [","] parameter ::= identifier [":" expression] defparameter ::= parameter ["=" expression] funcname ::= identifier

on the parameter_list line, you see "/" but there is no explanation of its effect anywhere...
I wrote the function bellow:

def f(t: int = 2, /): return t

This function acted the same way it would act if '/' wasn't in its parameter list. So what is the '/' about?

[deanhystad]

https://docs.python.org/3.8/whatsnew/3.8...parameters