1 # LuaDiffer: A simple lua diff library
   2 
   3 This is a simple lua module that performs a diff on two strings and returns a table of
   4 string chunks, or a diff of two lists and returns a list of list subsets.
   5 
   6 ## Example
   7 
   8 ```lua
   9 make_diff = require "diff"
  10 s1 = [[hello
  11 ...
  12 to the
  13 world]]
  14 s2 = [[hello
  15 ...
  16 *at* the
  17 world]]
  18 diff = make_diff(s1, s2)
  19 ```
  20 
  21 returns the table:
  22 
  23 ```lua
  24 {
  25   {old="hello\n...\n", old_first=1, old_last=2,
  26    new="hello\n...\n", new_first=1, new_last=2},
  27   {old="to the\n", old_first=3, old_last=3,
  28    new="*at* the\n", new_first=3, new_last=3},
  29   {old="world", old_first=4, old_last=4,
  30    new="world", new_first=4, new_last=4},
  31 }
  32 ```
  33 
  34 and running:
  35 
  36 ```lua
  37 diff:print{color=false}
  38 ```
  39 
  40 produces the output:
  41 
  42 ```
  43   hello
  44   ...
  45 - to the
  46 + *at* the
  47   world
  48 ```
  49 
  50 You can also diff tables:
  51 
  52 ```lua
  53 diff({1,2,3,4,5},{99,2,4,5,6})
  54 ```
  55 
  56 returns:
  57 
  58 ```lua
  59 {{old={1},    old_first=1, old_last=1, new={99},   new_first=1, new_last=1},
  60  {old={2},    old_first=2, old_last=2, new={2},    new_first=2, new_last=2},
  61  {old={3},    old_first=3, old_last=3, new={},     new_first=3, new_last=2},
  62  {old={4, 5}, old_first=4, old_last=5, new={4, 5}, new_first=3, new_last=4},
  63  {old={},     old_first=6, old_last=5, new={6},    new_first=5, new_last=5}}
  64 ```
  65 
  66 (when diffing tables, it is guaranteed that for matching chunks, .old and .new refer to
  67 the same table, so `chunk.old == chunk.new` will succeed)