errors: add some debugging functions

rc/errors.lua

@@ -15,3 +15,68 @@ do
         in_error = false
     end)
 end
+
+local colors = {
+  header = "#FF004D",
+  count  = "#33FF33",
+  index = "#708090",
+  name = "#8F8870",
+}
+
+local function dbg_get(var, depth, indent)
+  local a = ""
+  local text = ""
+  local name = ""
+  local vtype = type(var)
+  local vstring = tostring(var)
+
+  if vtype == "table" or vtype == "userdata" then
+    if vtype == "userdata" then var = getmetatable(var) end
+    -- element count and longest key
+    local count = 0
+    local longest_key = 3
+    for k,v in pairs(var) do
+      count = count + 1
+      longest_key = math.max(#tostring(k), longest_key)
+    end
+    text = text .. vstring .. " <span color='"..colors.count.."'>#" .. count .. "</span>"
+    -- descend a table
+    if depth > 0 then
+      -- sort keys FIXME: messes up sorting number
+      local sorted = {}
+      for k, v in pairs(var) do table.insert(sorted, { k, v }) end
+      table.sort(sorted, function(a, b) return tostring(a[1]) < tostring(b[1]) end)
+      -- go through elements
+      for _, p in ipairs(sorted) do
+        local key = p[1]; local value = p[2]
+        -- don't descend _M
+        local d; if key ~= "_M" then d = depth - 1 else d = 0 end
+        -- get content and add to output
+        local content = dbg_get(value, d, indent + longest_key + 1)
+        text = text .. '\n' .. string.rep(" ", indent) ..
+               string.format("<span color='"..colors.index.."'>%-"..longest_key.."s</span> %s",
+                             tostring(key), content)
+      end
+    end
+  else
+    if vtype == "tag" or vtype == "client" then
+      name = " [<span color='"..colors.name.."'>" .. var.name:sub(1,10) .. "</span>]"
+    end
+    text = text .. vstring .. name or ""
+  end
+
+  return text
+end
+
+function dbg(...)
+   local num = table.maxn(arg)
+   local text = "<span color='"..colors.header.."'>dbg</span> <span color='"..colors.count.."'>#"..num.."</span>"
+   local depth = 2
+
+   for i = 1, num do
+      local desc = dbg_get(arg[i], depth, 3)
+      text = text .. string.format("\n<span color='"..colors.index.."'>%2d</span> %s", i, desc)
+   end
+
+   naughty.notify{ text = text, timeout = 0, hover_timeout = 0.05, screen = screen.count() }
+end