The README.md is just the default page shown on github, https://github.com/EconForge/NLsolve.jl/blob/master/README.md
but there's no example of anonymous function use there. I think you need to
do something of the sort:
(x, fvec) -> begin
fvec[1] = (x[1]+3)*(x[2]^3-7)+18
fvec[2] = sin(x[2]*exp(x[1])-1)
end
Otherwise it's *@gensym *that is generating a new function name at each
iteration, I'm not sure you need it.
