A macro that turns a linear model (LmMod, produced by lm() in GLM.jl) into a function which takes a separate argument for each variable in the model.

predfunc.jl

macro predfunc(name, model)
    emod = eval(model)
    typeof(emod) == LmMod || error("Error: Wrong model type.")
    coefs = coef(emod)
    if typeof(emod.ff.rhs) == Symbol
        xes = [:intercept, emod.ff.rhs]
    elseif typeof(emod.ff.rhs) == Expr
        xes = emod.ff.rhs.args
        xes[1] = :intercept
    else
        error("Error: Can't make sense of formula $(emod.ff)")
    end
    length(coefs) == length(xes) || error("Error: Wrong number of variables in forumal $(emod.ff)")
    sums = Any[:($(coefs[i]) * $(xes[i])) for i in 1:length(xes)]
    sums[1].args[3] = 1.0
    lhs = Expr(:call)
    lhs.args = prepend!(sums, Any[:+])
    rhs = Expr(:call)
    push!(rhs.args, name)
    for i in 2:length(xes)
        push!(rhs.args, :($(xes[i])::Number))
    end
    ex = Expr(:(=))
    ex.args = Any[rhs, lhs]
    eval(ex)
end