This is a feature in Julia >=0.7 and was merged into Compat.jl for earlier Julia versions.

RequiredKeywordArguments

This package mostly provides the @rka macro enabling you to define required keyword arguments in a simple way.

using RequiredKeywordArguments

@rka f(;y) = y^2

declares y to be a required keyword argument. That means

f(y=2) # 4 # works
f() # RequiredKeywordArgumentError: `y` is a required keyword argument, please provide `y = ...`.