coerce VarFuns to FinFuns for SubobjectHom as well

src/categorical_algebra/CSets.jl

@@ -1123,9 +1123,10 @@ end
 const SubCSet{S} = Subobject{<:StructCSet{S}}
 const SubACSet{S} = Subobject{<:StructACSet{S}}
 
-# Componentwise subobjects
+# Componentwise subobjects: coerce VarFunctions to FinFunctions
 components(A::SubACSet{S}) where S = 
-  NamedTuple(k => Subobject(vs) for (k,vs) in pairs(components(hom(A)))
+  NamedTuple(k => Subobject(k ∈ ob(S) ? vs : FinFunction(vs)) for (k,vs) in 
+             pairs(components(hom(A)))
 )
 
 force(A::SubACSet) = Subobject(force(hom(A)))

src/categorical_algebra/FinSets.jl

@@ -348,7 +348,7 @@ VarFunction(f::AbstractVector{Int},cod::Int) = VarFunction(FinFunction(f,cod))
 VarFunction(f::FinDomFunction) = VarFunction{Union{}}(AttrVar.(collect(f)),codom(f))
 VarFunction{T}(f::FinDomFunction,cod::FinSet) where T = VarFunction{T}(collect(f),cod)
 FinFunction(f::VarFunction{T}) where T = FinFunction(
-  [f.fun(i) isa AttrVar ? f.fun(i).val : error("Cannot cast to FinFunction") 
+  [f(i) isa AttrVar ? f(i).val : error("Cannot cast to FinFunction") 
    for i in dom(f)], f.codom)
 FinDomFunction(f::VarFunction{T}) where T = f.fun
 Base.length(f::AbsVarFunction{T}) where T = length(collect(f.fun))

test/categorical_algebra/CSets.jl

@@ -733,29 +733,35 @@ X = @acset VES begin V=6; E=5; Label=5
   src=[1,2,3,4,4]; tgt=[3,3,4,5,6];
   vlabel=[:a,:b,:c,:d,:e,:f]; elabel=AttrVar.(1:5)
 end
-A, B = Subobject(X, V=1:4, E=1:3, Label=1:3), Subobject(X, V=3:6, E=3:5, Label=3:5)
-@test A ∧ B |> force == Subobject(X, V=3:4, E=3:3, Label=3:3) |> force
-expected = @acset VES begin V=2; E=1; Label=1;
-  src=1; tgt=2; vlabel=[:c,:d]; elabel=[AttrVar(1)]
-end
-@test is_isomorphic(dom(hom(A ∧ B )), expected)
-@test A ∨ B |> force == Subobject(X, V=1:6, E=1:5, Label=1:5) |> force
-@test ⊤(X) |> force == A ∨ B |> force
-@test ⊥(X) |> force == Subobject(X, V=1:0, E=1:0, Label=1:0) |> force
-@test force(implies(A, B)) == force(¬(A) ∨ B)
-@test ¬(A ∧ B) == ¬(A) ∨ ¬(B)
-@test ¬(A ∧ B) != ¬(A) ∨ B
-@test (A ∧ implies(A,B)) == B ∧ (A ∧ implies(A,B))
-@test (B ∧ implies(B,A)) == A ∧ (B ∧ implies(B,A))
-@test ¬(A ∨ (¬B)) == ¬(A) ∧ ¬(¬(B))
-@test ¬(A ∨ (¬B)) == ¬(A) ∧ B
-@test A ∧ ¬(¬(A)) == ¬(¬(A))
-@test implies((A∧B), A) == A∨B
-@test dom(hom(subtract(A,B))) == @acset VES begin V=3; E=2; Label=2
-  src=[1,2]; tgt=3; vlabel=[:a,:b,:c]; elabel=AttrVar.(1:2)
-end
 
-@test nv(dom(hom(~A))) == 3
+A′ = Subobject(X, V=1:4, E=1:3, Label=1:3) # component-wise representation
+B′ = Subobject(X, V=3:6, E=3:5, Label=3:5)
+A′′, B′′ = Subobject.(hom.([A′,B′])) # hom representation
+
+for (A,B) in [A′=>B′, A′′ =>B′′]
+  @test A ∧ B |> force == Subobject(X, V=3:4, E=3:3, Label=3:3) |> force
+  expected = @acset VES begin V=2; E=1; Label=1;
+    src=1; tgt=2; vlabel=[:c,:d]; elabel=[AttrVar(1)]
+  end
+  @test is_isomorphic(dom(hom(A ∧ B )), expected)
+  @test A ∨ B |> force == Subobject(X, V=1:6, E=1:5, Label=1:5) |> force
+  @test ⊤(X) |> force == A ∨ B |> force
+  @test ⊥(X) |> force == Subobject(X, V=1:0, E=1:0, Label=1:0) |> force
+  @test force(implies(A, B)) == force(¬(A) ∨ B)
+  @test ¬(A ∧ B) == ¬(A) ∨ ¬(B)
+  @test ¬(A ∧ B) != ¬(A) ∨ B
+  @test (A ∧ implies(A,B)) == B ∧ (A ∧ implies(A,B))
+  @test (B ∧ implies(B,A)) == A ∧ (B ∧ implies(B,A))
+  @test ¬(A ∨ (¬B)) == ¬(A) ∧ ¬(¬(B))
+  @test ¬(A ∨ (¬B)) == ¬(A) ∧ B
+  @test A ∧ ¬(¬(A)) == ¬(¬(A))
+  @test implies((A∧B), A) == A∨B
+  @test dom(hom(subtract(A,B))) == @acset VES begin V=3; E=2; Label=2
+    src=[1,2]; tgt=3; vlabel=[:a,:b,:c]; elabel=AttrVar.(1:2)
+  end
+
+  @test nv(dom(hom(~A))) == 3
+end
 
 # Limits of CSetTransformations between ACSets
 #---------------------------------------------