Advanced Search

Lua: Sane Granular Defaults for User Supplied Data

/ Published in: Other
Save to your folder(s)

Expand | Embed | Plain Text

Copy this code and paste it in your HTML 
  1. local mooDB
  2.  
  3. local defaults = {
  4.     a = {
  5.         foo = "bar"
  6.     },
  7.     b = 1,
  8.     c = {
  9.         bar = "foo"
  10.     },
  11. }
  12.  
  13. if not mooDB then
  14.     -- NOTE: This would not be in the actual real world code.  This
  15.     -- simulates user data, normally loaded from some sort
  16.     -- of datastore, which is SavedVariables in the case of
  17.     -- World of Warcraft.
  18.     mooDB = {
  19.         c = {
  20.             bop = "whee"
  21.         }
  22.     }
  23. end
  24.  
  25. function inheritdefaults(t, defaults)
  26.     for k,v in pairs(defaults) do
  27.         if t[k] then
  28.             if type(v) == "table" then
  29.                 inheritdefaults(t[k], v)
  30.             end
  31.         end
  32.     end
  33.  
  34.     local mt = getmetatable(t) or {}
  35.     function mt:__index(k)
  36.         return defaults[k]
  37.     end
  38.     return setmetatable(t, mt)
  39. end
  40.  
  41. inheritdefaults(mooDB, defaults)
  42.  
  43. assert(mooDB ~= defaults)
  44. assert(mooDB.a == defaults.a)
  45. assert(mooDB.c ~= defaults.c)
  46. assert(mooDB.a.foo == "bar")
  47. assert(mooDB.b == 1)
  48. assert(mooDB.c.bar == "foo")
  49. assert(mooDB.c.bop == "whee")

Report this snippet


Comments

RSS Icon Subscribe to comments

You need to login to post a comment.