+
+ # Store the allocated native array in a static variable
+ # For reusing later
+ var varonce = v.get_name("varonce")
+ v.add("if (unlikely({varonce}==NULL)) \{")
+
+ # The native array that will contains the elements to_s-ized.
+ # For fast concatenation.
+ var a = v.native_array_instance(type_string, v.int_instance(array.length))
+
+ v.add_decl("static {a.mtype.ctype} {varonce};")
+
+ # Pre-fill the array with the literal string parts.
+ # So they do not need to be filled again when reused
+ for i in [0..array.length[ do
+ var ne = array[i]
+ if not ne isa AStringFormExpr then continue
+ var e = v.expr(ne, null)
+ v.native_array_set(a, i, e)
+ end
+
+ v.add("\} else \{")
+ # Take the native-array from the store.
+ # The point is to prevent that some recursive execution use (and corrupt) the same native array
+ # WARNING: not thread safe! (FIXME?)
+ v.add("{a} = {varonce};")
+ v.add("{varonce} = NULL;")
+ v.add("\}")
+
+ # Stringify the elements and put them in the native array
+ var to_s_method = v.get_property("to_s", v.object_type)
+ for i in [0..array.length[ do
+ var ne = array[i]
+ if ne isa AStringFormExpr then continue
+ var e = v.expr(ne, null)
+ # Skip the `to_s` if the element is already a String
+ if not e.mcasttype.is_subtype(v.compiler.mainmodule, null, type_string) then
+ e = v.send(to_s_method, [e]).as(not null)
+ end
+ v.native_array_set(a, i, e)
+ end
+
+ # Fast join the native string to get the result
+ var res = v.send(v.get_property("native_to_s", a.mtype), [a])
+
+ # We finish to work with the native array,
+ # so store it so that it can be reused
+ v.add("{varonce} = {a};")