--- a/src/Grids/equidistant_grid.jl	Sun Sep 15 23:27:04 2024 +0200
+++ b/src/Grids/equidistant_grid.jl	Mon Sep 16 08:33:43 2024 +0200
@@ -151,9 +151,8 @@
 	return EquidistantGrid(range(limit_lower, limit_upper, length=size)) # TBD: Should it use LinRange instead?
 end
 
-
-equidistant_grid(hb::HyperBox, dims::Vararg{Int}) = equidistant_grid(hb.a, hb.b, dims...)
-# TODO: One dimensional grids shouldn't have vector eltype right?, Change here or in HyperBox?
+equidistant_grid(d::Interval, size::Int) = equidistant_grid(limits(d)..., size)
+equidistant_grid(hb::HyperBox, dims::Vararg{Int}) = equidistant_grid(limits(hb)..., dims...)
 
 function equidistant_grid(c::Chart, dims::Vararg{Int})
     lg = equidistant_grid(parameterspace(c), dims...)

--- a/src/Grids/manifolds.jl	Sun Sep 15 23:27:04 2024 +0200
+++ b/src/Grids/manifolds.jl	Mon Sep 16 08:33:43 2024 +0200
@@ -21,6 +21,21 @@
 Base.ndims(::ParameterSpace{D}) where D = D
 # TBD:  Should implement domain_dim?
 
+struct Interval{T} <: ParameterSpace{1}
+    a::T
+    b::T
+
+    function Interval(a,b)
+        a, b = promote(a, b)
+        new{typeof(a)}(a,b)
+    end
+end
+
+limits(i::Interval) = (i.a, i.b)
+
+unitinterval(T=Float64) = Interval(zero(T), one(T))
+
+
 struct HyperBox{T,D} <: ParameterSpace{D}
     a::SVector{D,T}
     b::SVector{D,T}
@@ -31,14 +46,12 @@
     HyperBox(convert(T,a), convert(T,b))
 end
 
-Interval{T} = HyperBox{T,1}
 Rectangle{T} = HyperBox{T,2}
 Box{T} = HyperBox{T,3}
 
 limits(box::HyperBox, d) = (box.a[d], box.b[d])
 limits(box::HyperBox) = (box.a, box.b)
 
-unitinterval(T=Float64) = unithyperbox(T,1)
 unitsquare(T=Float64) = unithyperbox(T,2)
 unitcube(T=Float64) = unithyperbox(T,3)
 unithyperbox(T, D) = HyperBox((@SVector zeros(T,D)), (@SVector ones(T,D)))

--- a/test/Grids/manifolds_test.jl	Sun Sep 15 23:27:04 2024 +0200
+++ b/test/Grids/manifolds_test.jl	Mon Sep 16 08:33:43 2024 +0200
@@ -11,6 +11,21 @@
     @test ndims(unittetrahedron()) == 3
 end
 
+@testset "Interval" begin
+    @test Interval <: ParameterSpace{1}
+
+    @test Interval(0,1) isa Interval{Int}
+    @test Interval(0,1.) isa Interval{Float64}
+
+    @test unitinterval() isa Interval{Float64}
+    @test unitinterval() == Interval(0.,1.)
+    @test limits(unitinterval()) == (0.,1.)
+
+    @test unitinterval(Int) isa Interval{Int}
+    @test unitinterval(Int) == Interval(0,1)
+    @test limits(unitinterval(Int)) == (0,1)
+end
+
 @testset "HyperBox" begin
     @test HyperBox{<:Any, 2} <: ParameterSpace{2}
     @test HyperBox([1,1], [2,2]) isa HyperBox{Int, 2}
@@ -19,12 +34,6 @@
     @test limits(HyperBox([1,2], [3,4]), 1) == (1,3)
     @test limits(HyperBox([1,2], [3,4]), 2) == (2,4)
 
-    @test unitinterval() isa HyperBox{Float64,1}
-    @test limits(unitinterval()) == ([0], [1])
-
-    @test unitinterval(Int) isa HyperBox{Int,1}
-    @test limits(unitinterval(Int)) == ([0], [1])
-
     @test unitsquare() isa HyperBox{Float64,2}
     @test limits(unitsquare()) == ([0,0],[1,1])