I can't tell how to use the defining forms at https://calculist.io/markup https://calculist.io/markup. These work: * \= 2*3 * \(x, y) = x+y However I'

I can't tell how to use the defining forms at https://calculist.io/markup https://calculist.io/markup. These work: * \= 2*3 * \(x, y) = x+y However I'm not sure how to define a new function. Here's what I tried: * \: foo (x, y) = x+y # no error * \=foo(2, 3) # error * \:barr = 2*3 # no error * \=barr # error