define Coord in new file, rename PJ_COORD to it

and leave out the unusable structs PJ_XY from proj_common.jl

gen/wrap_proj.jl

@@ -25,6 +25,7 @@ If Doxygen gives errors, it helps to turn off Latex and HTML output:
 
 using Clang
 using MacroTools
+using MacroTools: postwalk
 using EzXML
 using PROJ_jll
 
@@ -136,17 +137,14 @@ function rewriter(x::Expr)
         x2 = :(function $f($(fargs2...))
             $cc2
         end) |> prettify
-        return x2, argpos
+
+        # rename PJ_COORD to Coord
+        x3 = postwalk(x -> x === :PJ_COORD ? :Coord : x, x2)
+        return x3, argpos
     else
         # do not modify expressions that are no ccall function wrappers
         # argument positions do not apply, but something still needs to be returned
-
-        if x.head == :struct && x.args[2] == :PJ_COORD
-            # PJ_COORD becomes a subtype of StaticArrays' FieldVector
-            return prettify(pj_coord), nothing
-        else
-            return x, nothing
-        end
+        return x, nothing
     end
 end
 
@@ -156,15 +154,9 @@ const doc = readxml(xmlpath)
 includedir = joinpath(PROJ_jll.artifact_dir, "include")
 headerfiles = [joinpath(includedir, "proj.h")]
 
-const pj_coord = :(struct PJ_COORD <: FieldVector{4, Float64}
-    x::Float64
-    y::Float64
-    z::Float64
-    t::Float64
-end)
-
+# PJ_COORD becomes `Coord <: FieldVector{4, Float64}` and the rest is left out altogether
 # https://proj.org/development/reference/datatypes.html#c.PJ_COORD
-const coord_union = [:PJ_XYZT, :PJ_UVWT, :PJ_LPZT, :PJ_GEOD, :PJ_OPK,
+const coord_union = [:PJ_COORD, :PJ_XYZT, :PJ_UVWT, :PJ_LPZT, :PJ_GEOD, :PJ_OPK,
     :PJ_ENU, :PJ_XYZ, :PJ_UVW, :PJ_LPZ, :PJ_XY, :PJ_UV, :PJ_LP]
 
 wc = init(; headers = headerfiles,

src/Proj4.jl

@@ -12,9 +12,13 @@ export Projection, # proj_types.jl
 # geodesic support
 export geod_direct, geod_inverse, geod_destination, geod_distance
 
+# these are part of the deprecated PROJ API, and will be removed soon
 include("projection_codes.jl") # ESRI and EPSG projection strings
 include("proj_capi.jl") # low-level C-facing functions (corresponding to src/proj_api.h)
 include("proj_geodesic.jl") # low-level C-facing functions (corresponding to src/geodesic.h)
+
+# these are part of the new PROJ API
+include("coord.jl")
 include("proj_common.jl")
 include("proj_c.jl")
 include("error.jl")

src/coord.jl

@@ -0,0 +1,17 @@
+"""
+    Coord <: FieldVector{4, Float64}
+
+General purpose coordinate type, applicable in two, three and four dimensions. This is the
+default coordinate datatype used in PROJ.
+
+Elements can be retrieved either by index 1-4, or by field x, y, z, t. If a Coord does not
+represent a cartesian coordinate, using the index may be more clear, as the other coordinate
+types listed in the [PJ_COORD docs](https://proj.org/development/reference/datatypes.html#c.PJ_COORD)
+are not addressable by name.
+"""
+struct Coord <: FieldVector{4, Float64}
+    x::Float64
+    y::Float64
+    z::Float64
+    t::Float64
+end

src/proj_c.jl

@@ -367,43 +367,43 @@ function proj_degree_output(P, dir)
 end
 
 function proj_trans(P, direction, coord)
-    ccall((:proj_trans, libproj), PJ_COORD, (Ptr{PJ}, PJ_DIRECTION, PJ_COORD), P, direction, coord)
+    ccall((:proj_trans, libproj), Coord, (Ptr{PJ}, PJ_DIRECTION, Coord), P, direction, coord)
 end
 
 function proj_trans_array(P, direction, n, coord)
-    ccall((:proj_trans_array, libproj), Cint, (Ptr{PJ}, PJ_DIRECTION, Csize_t, Ptr{PJ_COORD}), P, direction, n, coord)
+    ccall((:proj_trans_array, libproj), Cint, (Ptr{PJ}, PJ_DIRECTION, Csize_t, Ptr{Coord}), P, direction, n, coord)
 end
 
 function proj_trans_generic(P, direction, x, sx, nx, y, sy, ny, z, sz, nz, t, st, nt)
     ccall((:proj_trans_generic, libproj), Csize_t, (Ptr{PJ}, PJ_DIRECTION, Ptr{Cdouble}, Csize_t, Csize_t, Ptr{Cdouble}, Csize_t, Csize_t, Ptr{Cdouble}, Csize_t, Csize_t, Ptr{Cdouble}, Csize_t, Csize_t), P, direction, x, sx, nx, y, sy, ny, z, sz, nz, t, st, nt)
 end
 
 function proj_coord(x = 0.0, y = 0.0, z = 0.0, t = 0.0)
-    ccall((:proj_coord, libproj), PJ_COORD, (Cdouble, Cdouble, Cdouble, Cdouble), x, y, z, t)
+    ccall((:proj_coord, libproj), Coord, (Cdouble, Cdouble, Cdouble, Cdouble), x, y, z, t)
 end
 
 function proj_roundtrip(P, direction, n, coord)
-    ccall((:proj_roundtrip, libproj), Cdouble, (Ptr{PJ}, PJ_DIRECTION, Cint, Ptr{PJ_COORD}), P, direction, n, coord)
+    ccall((:proj_roundtrip, libproj), Cdouble, (Ptr{PJ}, PJ_DIRECTION, Cint, Ptr{Coord}), P, direction, n, coord)
 end
 
 function proj_lp_dist(P, a, b)
-    ccall((:proj_lp_dist, libproj), Cdouble, (Ptr{PJ}, PJ_COORD, PJ_COORD), P, a, b)
+    ccall((:proj_lp_dist, libproj), Cdouble, (Ptr{PJ}, Coord, Coord), P, a, b)
 end
 
 function proj_lpz_dist(P, a, b)
-    ccall((:proj_lpz_dist, libproj), Cdouble, (Ptr{PJ}, PJ_COORD, PJ_COORD), P, a, b)
+    ccall((:proj_lpz_dist, libproj), Cdouble, (Ptr{PJ}, Coord, Coord), P, a, b)
 end
 
 function proj_xy_dist(a, b)
-    ccall((:proj_xy_dist, libproj), Cdouble, (PJ_COORD, PJ_COORD), a, b)
+    ccall((:proj_xy_dist, libproj), Cdouble, (Coord, Coord), a, b)
 end
 
 function proj_xyz_dist(a, b)
-    ccall((:proj_xyz_dist, libproj), Cdouble, (PJ_COORD, PJ_COORD), a, b)
+    ccall((:proj_xyz_dist, libproj), Cdouble, (Coord, Coord), a, b)
 end
 
 function proj_geod(P, a, b)
-    ccall((:proj_geod, libproj), PJ_COORD, (Ptr{PJ}, PJ_COORD, PJ_COORD), P, a, b)
+    ccall((:proj_geod, libproj), Coord, (Ptr{PJ}, Coord, Coord), P, a, b)
 end
 
 function proj_context_errno(ctx = C_NULL)
@@ -439,7 +439,7 @@ function proj_log_func(app_data, logf, ctx = C_NULL)
 end
 
 function proj_factors(P, lp)
-    ccall((:proj_factors, libproj), PJ_FACTORS, (Ptr{PJ}, PJ_COORD), P, lp)
+    ccall((:proj_factors, libproj), PJ_FACTORS, (Ptr{PJ}, Coord), P, lp)
 end
 
 function proj_info()
@@ -1489,7 +1489,7 @@ end
 the index in operations that would be used to transform coord. Or -1 in case of error, or no match.
 """
 function proj_get_suggested_operation(operations, direction, coord, ctx = C_NULL)
-    ccall((:proj_get_suggested_operation, libproj), Cint, (Ptr{PJ_CONTEXT}, Ptr{PJ_OBJ_LIST}, PJ_DIRECTION, PJ_COORD), ctx, operations, direction, coord)
+    ccall((:proj_get_suggested_operation, libproj), Cint, (Ptr{PJ_CONTEXT}, Ptr{PJ_OBJ_LIST}, PJ_DIRECTION, Coord), ctx, operations, direction, coord)
 end
 
 """

src/proj_common.jl

@@ -8,14 +8,6 @@ const PROJ_VERSION_MAJOR = 7
 const PROJ_VERSION_MINOR = 2
 const PROJ_VERSION_PATCH = 0
 const PJ_DEFAULT_CTX = 0
-
-struct PJ_COORD <: FieldVector{4, Float64}
-    x::Float64
-    y::Float64
-    z::Float64
-    t::Float64
-end
-
 const PJ_AREA = Cvoid
 
 struct P5_FACTORS

test/proj6api.jl

@@ -85,7 +85,7 @@ end
     a = Proj4.proj_coord(12, 55)
     @test a isa AbstractVector
     @test a isa FieldVector{4, Float64}
-    @test a isa Proj4.PJ_COORD
+    @test a isa Proj4.Coord
     @test eltype(a) == Float64
     @test length(a) == 4
     @test sum(a) == 12 + 55