Sigma migrations

[ohaaga]

Behaviour shown in the tests here isn't what I would expect. I would expect to specify the dictionaries in the "forward" direction, and get sigma migrations from either possible functor between discrete one and two object schemas.

[kris-brown]

Reposting the gist content here

using AlgebraicABMs, AlgebraicRewriting, Test

@present SchX(FreeSchema) begin X::Ob end
@acset_type XType(SchX)

@present SchXY(FreeSchema) begin 
  X::Ob
  Y::Ob
end
@acset_type XYType(SchXY)

empty_x = @acset XType begin end
empty_xy = @acset XYType begin end

x = representable(XType, :X) 
x′ = representable(XYType, :X)
y = representable(XYType, :Y) 


x_to_x = Migrate(
	Dict(:X => :X),
	Dict(),
	SchX, XType, 
	SchXY, XYType;
	delta=false
)

x_to_y = Migrate(
	Dict(:X => :Y),
	Dict(),
	SchX, XType, 
	SchXY, XYType;
	delta=false
)

@test x_to_x(empty_x) == empty_xy
@test x_to_y(empty_x) == empty_xy

@test x_to_x(x) == x′
@test x_to_y(x) == y