change implementation

src/parsing.jl

@@ -18,8 +18,8 @@ a `QuoteNode` or an expression beginning with
 If input is not a valid column identifier,
 returns `nothing`.
 """
-get_column_expr(x) = nothing
-function get_column_expr(e::Expr)
+get_column_expr(x; allow_multicol::Bool = false) = nothing
+function get_column_expr(e::Expr; allow_multicol::Bool = false)
     e.head == :$ && return e.args[1]
     onearg(e, :AsTable) && return :($AsTable($(e.args[2])))
     if onearg(e, :cols)
@@ -29,14 +29,18 @@ function get_column_expr(e::Expr)
     if e.head === :call
         e1 = e.args[1]
         if e1 === :All || e1 === :Not || e1 === :Between || e1 == :Cols
-            s = "Multi-column references outside of @select, @rselect, @select!" *
-             " and @rselect! must be wrapped in AsTable"
-            throw(ArgumentError(s))
+            if allow_multicol
+                return e
+            else
+                s = "Multi-column references outside of @select, @rselect, @select!" *
+                 " and @rselect! must be wrapped in AsTable"
+                throw(ArgumentError(s))
+            end
         end
     end
     return nothing
 end
-get_column_expr(x::QuoteNode) = x
+get_column_expr(x::QuoteNode; allow_multicol::Bool = false) = x
 
 get_column_expr_rename(x) = nothing
 function get_column_expr_rename(e::Expr)
@@ -352,21 +356,7 @@ function fun_to_vec(ex::Expr;
     # :x
     # handled below via dispatch on ::QuoteNode
 
-    # Do we give special treatment to All() etc?
-    # Only applies when allow_multicol is
-    # set to true.
-    # Otherwise, these are treated as
-    # normal functions
-    if allow_multicol
-        exhead = ex.head
-        if ex.head === :call
-            if exhead === :All || exhead === :Not || exhead === :Cols || exhead === :Between
-                return ex
-            end
-        end
-    end
-
-    ex_col = get_column_expr(ex)
+    ex_col = get_column_expr(ex; allow_multicol = allow_multicol)
     if ex_col !== nothing
         return ex_col
     end

test/runtests.jl

@@ -15,7 +15,8 @@ my_tests = ["dataframes.jl",
             "byrow.jl",
             "astable.jl",
             "astable_flag.jl",
-            "passmissing.jl"]
+            "passmissing.jl",
+            "multicol.jl"]
 
 println("Running tests:")