method for human to make formula with FunctionTerm

[PharmCat]

Method for human to make formula with FunctionTerm in expression.

I try to make dynamic formula like this:

module XXX
using StatsModels
global i = Symbol()
for  v in [:a, :b]
    i = v
    model = eval(:(
    StatsModels.capture_call(log, (($i,)->log($i)),
    (i,),
    $(Expr(:copyast, :($(QuoteNode(:(log($i))))))),
    [StatsModels.Term(i)]
    )
    ~ Term(:AX)))
#some code with lm()
end
end

for simple Term it easy:

:(Term(:y) ~ ConstantTerm(1) + Term(:a) + Term(:b) + Term(:a) & Term(:b))

at the end i get:

ERROR: MethodError: no method matching (::Main.XXX.var"#7#8")(::Float64)
The applicable method may be too new: running in world age 30095, while current world is 30096.

[ndgnuh]

My current workaround:

function single_functional_term(f, x)
	symbol = Expr(:call, Symbol(f), x)
	fanon = eval(:(($x,) -> log($x)))
	StatsModels.capture_call(f, fanon, (x,), symbol, [Term(x)])
end

f = let res = Term(:y)
	pres = mapreduce(vcat, 1:3) do i
		s = Symbol("x$i")
		[Term(s), single_functional_term(log, s)]
	end
	FormulaTerm(res, (pres...,))
end

It doesn't work on multiple arity functions though, like (x, y) -> log(x*y)

---

My second hack by abusing the @formula macro:

function functional_term(f, arg_expr...)
	expr = Expr(:call, Symbol(f), arg_expr...)
	eval(:(@formula somethingsomethingvarhopefullynodup ~ $expr)).rhs
end

t1 = functional_term(log, :(x * y))
t2 = functional_term(*, :x, :y)
t3 = functional_term(*, [Symbol("x$i") for i in 1:4]...)
display(t1)
# (x,y)->log(x * y)
display(t2)
# x(unknown)
# y(unknown)
# x(unknown) & y(unknown)
display(t3)
# x1(unknown)
# x2(unknown)
# x3(unknown)
# x4(unknown)
# x1(unknown) & x2(unknown)
# x1(unknown) & x3(unknown)
# x2(unknown) & x3(unknown)
# x1(unknown) & x4(unknown)
# x2(unknown) & x4(unknown)
# x3(unknown) & x4(unknown)
# x1(unknown) & x2(unknown) & x3(unknown)
# x1(unknown) & x2(unknown) & x4(unknown)
# x1(unknown) & x3(unknown) & x4(unknown)
# x2(unknown) & x3(unknown) & x4(unknown)
# x1(unknown) & x2(unknown) & x3(unknown) & x4(unknown)

[kleinschmidt]

See #183 ... with that proposal you can construct them a lot more easily since there's no need for an anonymous function.

For now I'd suggest using @ndgnuh solution, except you can do @eval(@formula(0 ~ $expr)).rhs (use 0 on the LHS)

[kleinschmidt]

There's definitely no reason to deal with capture_call directly, that's just to make the macro itself a bit cleaner to write :) Once you're doing any kind of eval you might as well use @formula

[PharmCat]

seems second case not working with GLM

[kleinschmidt]

#183 is merged and there are examples in the tests of how to create function terms programatically!