improve structs typing

src/particles.jl

@@ -1,7 +1,7 @@
 abstract type AbstractParticles end
 
 """
-    struct Particles{Backend,N,M,I,T1,T2} <: AbstractParticles
+    Particles{Backend,N,I,T1,T2} <: AbstractParticles
 
 A struct representing a collection of particles.
 
@@ -14,7 +14,7 @@ A struct representing a collection of particles.
 - `min_xcell`: Minimum number of particles per cell
 - `np`: Number of particles
 """
-struct Particles{Backend,N,M,I,T1,T2} <: AbstractParticles
+struct Particles{Backend,N,I,T1,T2} <: AbstractParticles
     coords::NTuple{N,T1}
     index::T2
     nxcell::I
@@ -23,15 +23,15 @@ struct Particles{Backend,N,M,I,T1,T2} <: AbstractParticles
     np::I
 
     function Particles(
-        backend,
+        ::Type{B},
         coords::NTuple{N,T1},
         index::T2,
         nxcell::I,
         max_xcell::I,
         min_xcell::I,
         np::I,
-    ) where {N,I,T1,T2}
-        return new{backend,N,max_xcell,I,T1,T2}(
+    ) where {B,N,I,T1,T2}
+        return new{B,N,I,T1,T2}(
             coords, index, nxcell, max_xcell, min_xcell, np
         )
     end
@@ -40,7 +40,7 @@ end
 function Particles(coords, index::CPUCellArray, nxcell, max_xcell, min_xcell, np)
     return Particles(CPUBackend, coords, index, nxcell, max_xcell, min_xcell, np)
 end
-struct MarkerChain{Backend,N,M,I,T1,T2,T3,TV} <: AbstractParticles
+struct MarkerChain{Backend,N,I,T1,T2,T3,TV} <: AbstractParticles
     coords::NTuple{N,T1}    # current x-coord in 2D, (x,y)
     coords0::NTuple{N,T1}   # x-coord in 2D, (x,y) from the previous time step
     h_vertices::T2          # topography at the vertices of the grid (current)
@@ -51,7 +51,7 @@ struct MarkerChain{Backend,N,M,I,T1,T2,T3,TV} <: AbstractParticles
     min_xcell::I
 
     function MarkerChain(
-        backend,
+        ::Type{B},
         coords::NTuple{N,T1},
         coords0::NTuple{N,T1},
         h_vertices::T2,
@@ -60,8 +60,8 @@ struct MarkerChain{Backend,N,M,I,T1,T2,T3,TV} <: AbstractParticles
         index::T3,
         min_xcell::I,
         max_xcell::I,
-    ) where {N,I,T1,T2,T3,TV}
-        return new{backend,N,max_xcell,I,T1,T2,T3,TV}(
+    ) where {B,N,I,T1,T2,T3,TV}
+        return new{B,N,I,T1,T2,T3,TV}(
             coords, coords0, h_vertices, h_vertices0, cell_vertices, index, max_xcell, min_xcell
         )
     end
@@ -75,20 +75,18 @@ struct PassiveMarkers{Backend,T} <: AbstractParticles
     coords::T
     np::Int64
 
-    function PassiveMarkers(backend, coords::NTuple{N,T}) where {N,T}
+    function PassiveMarkers(::Type{B}, coords::NTuple{N,T}) where {B,N,T}
         # np = length(coords[1].data)
         np = length(coords[1])
-        return new{backend,typeof(coords)}(coords, np)
+        return new{B,typeof(coords)}(coords, np)
     end
-    function PassiveMarkers(backend, coords::AbstractArray)
+    function PassiveMarkers(::Type{B}, coords::AbstractArray) where B
         np = length(coords)
-        return new{backend,typeof(coords)}(coords, np)
+        return new{B,typeof(coords)}(coords, np)
     end
 end
 
-function PassiveMarkers(coords::Union{AbstractArray,NTuple{N,T}}) where {N,T}
-    return PassiveMarkers(CPUBackend, coords)
-end
+PassiveMarkers(coords::Union{AbstractArray,NTuple{N,T}}) where {N,T} = PassiveMarkers(CPUBackend, coords)
 
 # useful functions
 
@@ -127,4 +125,4 @@ end
         Base.@_inline_meta
         cell_index(x[i], xv[i])
     end
-end
+end