In shell, f x y z, x y z are all augments to f. Doesn't matter if f takes one argument, all are passed to the function.
With many functional languages this gets very confusing. IE what ie what does `f f x` do? In shell I know for sure.
In the example f f x, it might be easy to parse. But in f x y z, any of x y z might be functions.
In Ruby however it is a bit more ugly
def f x
x + 1
end
puts f f 1
OCaml parses a b c as ((a b) c). In case the compiler can determine that a is a function taking 2 arguments, it will optimise the code, so that it’s effectively a(b, c). But in general, that’s not possible, especially in the case where the compiler determines that a is a function with a single argument (in which case, it’s return value must be another function, which is in turn called with c) or when a is a first-class function (e.g. passed as an argument)
xargs -0 -n1 bash -c 'mv $1 ${1//.js/.ts}' --
Everything to the right of xargs is a string argument passed to xargs.