--- a/src/SbpOperators/SbpOperators.jl	Fri Sep 25 14:19:15 2020 +0200
+++ b/src/SbpOperators/SbpOperators.jl	Sat Sep 26 15:20:18 2020 +0200
@@ -13,4 +13,21 @@
 include("quadrature/quadrature.jl")
 include("quadrature/inverse_diagonal_inner_product.jl")
 include("quadrature/inverse_quadrature.jl")
+
+abstract type SbpOperator{T,R,D} <: TensorMapping{T,R,D} end
+
+"""
+    grid(::ColocationOperator)
+
+Return the the grid which the sbp-operator lives on
+"""
+function grid end
+
+abstract type ColocationOperator{T,R,D} <: SbpOperator{T,R,D} end
+
+LazyTensors.range_size(co::ColocationOperator) = size(grid(co))
+LazyTensors.domain_size(co::ColocationOperator) = size(grid(co))
+
+# Allt ovan kanske är overkill.. Eventuellt bara lättare och tydligare att alla typer definerar sina range och domain size hur dom vill. (I praktiken typ alltid genom att ha gridden som ett fält i structen.)
+
 end # module