was surprised to find this is a valid Julia code:
julia> ==(==,==)
true
This fails, though:
julia> == == ==
ERROR: syntax: "==" is not a unary operator
I think both should parse the same, not that anyone sane would write either expression (hmm…)
You just need parentheses:
julia> (==) == (==)
true
This isn’t really abuse — nearly all “operators” are functions themselves and can be called as such. They just have special parsing that can make it tricky for Julia to see the function call as a function call or the infix operator syntax as infix syntax, so parentheses are sometimes required to disambiguate.
Or even
julia> (==) == ==
true
just to prevent the first == from being tried as a unary operator.