Handle obj.field expression in @transform macro

src/geoops/macros.jl

@@ -66,19 +66,23 @@ _getcolexpr(expr) = :(getproperty(geotable, $(_nameexpr(expr))))
 function _colnames(expr)
   colnames = []
   if expr isa Expr
-    _colargs!(expr, colnames)
+    _colargs!(colnames, expr)
   end
   colnames
 end
 
-function _colargs!(expr, colnames)
-  start = Meta.isexpr(expr, [:call, :macrocall]) ? 2 : 1
-  for i in start:length(expr.args)
-    arg = expr.args[i]
-    if _iscolname(arg)
-      push!(colnames, arg)
-    elseif arg isa Expr
-      _colargs!(arg, colnames)
+function _colargs!(colnames, expr)
+  if Meta.isexpr(expr, :., 2) && expr.args[2] isa QuoteNode # handle expressions of the form obj.field
+    _colargs!(colnames, expr.args[1])
+  else # descend on function/macro arguments
+    start = Meta.isexpr(expr, [:call, :macrocall]) ? 2 : 1
+    for i in start:length(expr.args)
+      arg = expr.args[i]
+      if _iscolname(arg)
+        push!(colnames, arg)
+      elseif arg isa Expr
+        _colargs!(colnames, arg)
+      end
     end
   end
 end

test/operations.jl

@@ -491,6 +491,10 @@
     ndata = @transform(sdata, :x_str = join([:x, "test"]))
     @test ndata.x_str == [join([x, "test"]) for x in sdata.x]
 
+    # obj.field syntax
+    ndata = @transform(sdata, :cx = coords(:geometry).x)
+    @test ndata.cx == [coords(p).x for p in sdata.geometry]
+
     # column replacement
     table = (x=rand(10), y=rand(10), z=rand(10))
     sdata = georef(table, rand(Point, 10))