--[[--------------------------< A D D _ V A N C _ E R R O R >----------------------------------------------------
Adds a single Vancouver system error message to the template's output regardless of how many error actually exist.
To prevent duplication, added_vanc_errs is nil until an error message is emitted.
]]
local added_vanc_errs; -- flag so we only emit one Vancouver error / category
local function add_vanc_error ()
if not added_vanc_errs then
added_vanc_errs = true; -- note that we've added this category
table.insert( z.message_tail, { set_error( 'vancouver', {}, true ) } );
end
end
