[PATCH 1/7] box/console: Add mapping for direct symbols

[Cyrill Gorcunov]

Sole symbols (such as box.NULL) are not processed
by serpent "custom" symbols feature, since they
are not in table.

Thus we should process them separately. Without it
we have

 > require('console').set_default_output("lua,block")
 > ;
 > box.NULL
 > "cdata<void %*>: NULL";

instead of

 > box.NULL
 > box.NULL;

as it should be.

Part-of #3834
---
 src/box/lua/console.lua | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/box/lua/console.lua b/src/box/lua/console.lua
index 64086cf5b..9420bee69 100644
--- a/src/box/lua/console.lua
+++ b/src/box/lua/console.lua
@@ -40,12 +40,24 @@ output_handlers["yaml"] = function(status, opts, ...)
     return internal.format({ error = err })
 end
 
+-- A map for internal symbols in case if they
+-- are not inside tables and serpent won't be
+-- able to handle them properly.
+local lua_map_direct_symbols = {
+    [box.NULL]      = 'box.NULL',
+}
+
 output_handlers["lua"] = function(status, opts, ...)
     --
     -- Don't print nil if there is no data
     if not ... then
         return ""
     end
+    for k,v in pairs(lua_map_direct_symbols) do
+        if k == ... then
+            return v
+        end
+    end
     --
     -- Map internal symbols which serpent doesn't know
     -- about to a known representation.
-- 
2.20.1