support StatsModels 0.7 (#13)

* support StatsModels 0.7

* detect InteractionTerms and throw error

* update doc

* tupleterm

* unused imports

* add a few more tests

* add test

* mark as broken

* brokener

---------

Co-authored-by: Dave Kleinschmidt <dave.f.kleinschmidt@gmail.com>

Author: palday

Project.toml

@@ -1,7 +1,7 @@
 name = "RegressionFormulae"
 uuid = "545c379f-4ec2-4339-9aea-38f2fb6a8ba2"
 authors = ["Dave Kleinschmidt", "Phillip Alday"]
-version = "0.1.1"
+version = "0.1.2"
 
 [deps]
 Combinatorics = "861a8166-3701-5b0c-9a16-15d98fcdc6aa"
@@ -10,7 +10,7 @@ StatsModels = "3eaba693-59b7-5ba5-a881-562e759f1c8d"
 [compat]
 Combinatorics = "1"
 StatsBase = "0.33"
-StatsModels = "0.6.7"
+StatsModels = "0.7"
 julia = "1.6"
 
 [extras]

src/RegressionFormulae.jl

@@ -4,9 +4,8 @@ using StatsModels
 using Combinatorics
 using Base.Iterators
 
-using StatsModels: apply_schema
+using StatsModels: apply_schema, TupleTerm
 
-const TermTuple = NTuple{N, AbstractTerm} where N
 const Schemas = Union{StatsModels.Schema, StatsModels.FullRank}
 
 include("fulldummy.jl")

src/fulldummy.jl

@@ -8,7 +8,7 @@ function StatsModels.apply_schema(
     sch::StatsModels.FullRank,
     Mod::Type{<:RegressionModel},
 )
-    fulldummy(apply_schema.(t.args_parsed, Ref(sch), Mod)...)
+    fulldummy(apply_schema.(t.args, Ref(sch), Mod)...)
 end
 
 function fulldummy(t::CategoricalTerm)

src/nesting.jl

@@ -21,12 +21,12 @@ function Base.:(/)(outer::CategoricalTerm, inner::AbstractTerm)
     return outer + fulldummy(outer) & inner
 end
 
-function Base.:(/)(outer::CategoricalTerm, inner::TermTuple)
+function Base.:(/)(outer::CategoricalTerm, inner::TupleTerm)
     fd = fulldummy(outer)
     return mapfoldl(x -> fd & x, +, inner; init=outer)
 end
 
-function Base.:(/)(outer::TermTuple, inner::Union{AbstractTerm, TermTuple})
+function Base.:(/)(outer::TupleTerm, inner::Union{AbstractTerm, TupleTerm})
     return outer[1:end-1] + last(outer) / inner
 end
 
@@ -37,7 +37,7 @@ function Base.:(/)(outer::InteractionTerm, inner::AbstractTerm)
     return outer + outer & inner
 end
 
-function Base.:(/)(outer::InteractionTerm, inner::TermTuple)
+function Base.:(/)(outer::InteractionTerm, inner::TupleTerm)
     # we should only get here via expansion where the interaction term,
     # but who knows what devious things users will try
     _fulldummycheck(outer)
@@ -54,13 +54,12 @@ function StatsModels.apply_schema(
     sch::StatsModels.FullRank,
     Mod::Type{<:RegressionModel},
 )
-    length(t.args_parsed) == 2 ||
+    length(t.args) == 2 ||
         throw(ArgumentError("malformed nesting term: $t (Exactly two arguments required)"))
 
-    any(x -> isa(x, ConstantTerm), t.args_parsed) && return t
+    any(x -> isa(x, ConstantTerm), t.args) && return t
 
-    args = apply_schema.(t.args_parsed, Ref(sch), Mod)
+    args = apply_schema.(t.args, Ref(sch), Mod)
 
     return first(args) / last(args)
 end
-

src/power.jl

@@ -6,15 +6,17 @@ combinations_upto(x, n) = Iterators.flatten(combinations(x, i) for i in 1:n)
 Generate all interactions of terms up to order ``n``.
 
 !!! warning
-    If any term is an `InteractionTerm`, then nonsensical interactions may
-    arise, e.g. `a & a & b`.
+    Embedded `InteractionTerms` (i.e. `(a + b + c & d)^2`) are not currently
+    supported and result in an error.
 """
-function Base.:(^)(args::TermTuple, deg::ConstantTerm{<:Integer})
+function Base.:(^)(args::TupleTerm, deg::ConstantTerm{<:Integer})
     deg.n > 0 || throw(ArgumentError("power should be greater than zero (got $deg)"))
+    any(t isa InteractionTerm for t in args) &&
+        throw(ArgumentError("powers of interaction terms not currently supported"))
     tuple(((&)(terms...) for terms in combinations_upto(args, deg.n))...)
 end
 
-function Base.:(^)(::TermTuple, deg::AbstractTerm)
+function Base.:(^)(::TupleTerm, deg::AbstractTerm)
     throw(ArgumentError("power should be an integer constant (got $deg)"))
 end
 
@@ -23,10 +25,12 @@ function StatsModels.apply_schema(
     sch::StatsModels.FullRank,
     ctx::Type{<:RegressionModel}
 )
-    length(t.args_parsed) == 2 ||
+    length(t.args) == 2 ||
         throw(ArgumentError("invalid term $t: should have exactly two arguments"))
-    first, second = t.args_parsed
-    second isa ConstantTerm{<:Integer} ||
-        throw(ArgumentError("invalid term $t: power should be an integer (got $second)"))
-    apply_schema.(first^second, Ref(sch), ctx)
+    first, second = t.args
+
+    base = apply_schema(first, sch, ctx)
+    return base^second
 end
+
+# StatsModels

test/power.jl

@@ -6,7 +6,6 @@ include("dummymod.jl")
 
 dat = (; y=zeros(3), a=1:3, b=11:13, c=21:23, d=31:33, e=["u", "i", "o"])
 
-
 @testset "error checking" begin
     @test_throws ArgumentError (term(:b),) ^ term(:a)
     @test_throws ArgumentError (term(:b),) ^ term(2.5)
@@ -31,11 +30,29 @@ end
     m = fit(DummyMod, @formula(y ~ (a + b + e)^2), dat)
     @test coefnames(m) == ["(Intercept)", "a", "b", "e: o", "e: u",
                            "a & b", "a & e: o", "a & e: u", "b & e: o", "b & e: u"]
+
+    # make sure inner function terms work
+    m = fit(DummyMod, @formula(y ~ (a + b + log(a + b))^3), dat)
+    @test coefnames(m) ==  ["(Intercept)", "a", "b", "log(a + b)",
+                             "a & b", "a & log(a + b)", "b & log(a + b)",
+                             "a & b & log(a + b)"]
+
+    # cursed but should technically work
+    m = fit(DummyMod, @formula(y ~ (a + b + (c + d)^1)^2), dat)
+    @test coefnames(m) == ["(Intercept)", "a", "b", "c", "d",
+                           "a & b", "a & c", "a & d",
+                           "b & c", "b & d", "c & d"]
+    # not actually an InteractionTerm even if it's mathematically equivalent for
+    # ContinuousTerms
+    # throws an error and is broken
+    # https://github.com/JuliaStats/StatsModels.jl/issues/290
+    # m = fit(DummyMod, @formula(y ~ (a + protect(c * d))^2), dat)
+    # @test coefnames(m) == ["(Intercept)", "a", "c * d", "a & c *d "]
+    # to remind us :this: is broken
+    @test_broken false
 end
 
 @testset "embedded interactions" begin
-    m = fit(DummyMod, @formula(y ~ (a + b + c * d)^3), dat)
-    cn = coefnames(m)
-    @test_broken !("a & c & c & d" in cn)
-    @test_broken cn == unique(cn)
+    @test_throws ArgumentError fit(DummyMod, @formula(y ~ (a + b + c & d)^3), dat)
+    @test_throws ArgumentError fit(DummyMod, @formula(y ~ (a + b + c * d)^3), dat)
 end