Allow interpolation of properties

Author: phipsgabler

src/sugar.jl

@@ -123,12 +123,17 @@ function parse_obj_lenses(ex)
             lens = :($IndexLens($index))
         end
     elseif @capture(ex, front_.property_)
-        property isa Union{Symbol,String} || throw(ArgumentError(
-            string("Error while parsing :($ex). Second argument to `getproperty` can only be",
-                   "a `Symbol` or `String` literal, received `$property` instead.")
-        ))
         obj, frontlens = parse_obj_lenses(front)
-        lens = :($PropertyLens{$(QuoteNode(property))}())
+        if property isa Union{Symbol,String}
+            lens = :($PropertyLens{$(QuoteNode(property))}())
+        elseif is_interpolation(property)
+            lens = :($PropertyLens{$(esc(property.args[1]))}())
+        else
+            throw(ArgumentError(
+                string("Error while parsing :($ex). Second argument to `getproperty` can only be",
+                       "a `Symbol` or `String` literal, received `$property` instead.")
+            ))
+        end
     elseif @capture(ex, f_(front_))
         obj, frontlens = parse_obj_lenses(front)
         lens = :($FunctionLens($(esc(f))))

test/test_core.jl

@@ -509,6 +509,9 @@ end
     @test @lens($lbc)== lbc
     @test @lens(_.a ∘ $lbc) == @lens(_.a) ∘ lbc
     @test @lens(_.a ∘ $lbc ∘ _[1] ∘ $lbc) == @lens(_.a) ∘ lbc ∘ @lens(_[1]) ∘ lbc
+
+    name = :a
+    @test @lens(_.$name) == @lens(_.a)
 end
 
 end