Split function for lua

Summary

Example

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Code

-- ##########################################################################
-- # split() function for lua
-- # Markus Nentwig 2007
-- # This code is in the public domain and provided without any warranty.
-- ##########################################################################

local split=
   function(text, sep, plain)
      local res={}
      local searchPos=1
      while true do
	 local matchStart, matchEnd=string.find(text, sep, searchPos, plain)
	 if matchStart and matchEnd >= matchStart then
	    -- insert string up to separator into result
	    table.insert(res, string.sub(text, searchPos, matchStart-1))
	    -- continue search after separator
	    searchPos=matchEnd+1
	 else
	    -- insert whole reminder as result
	    table.insert(res, string.sub(text, searchPos))
	    break
	 end
      end
      return res
   end

-- ##########################################################################
-- # Self test / examples
-- ##########################################################################
local verif=
   function(teststr, pat, plain, check)
      local res=split(teststr, pat, plain)
      res=table.concat(res, "*")
      assert(res==check, "split self test assertion failed")
   end

-- "|-" as separator. In pattern quoted via %
verif("one|-two|-three|-four|-five", "%|%-", false, "one*two*three*four*five")

-- leading/trailing/duplicate separators cause empty string
verif("|-one|-two|-three|-four|-|-five|-", "%|%-", false, "*one*two*three*four**five*")

-- separator using pattern
verif("one1two22three333four4444five", "%d+", false, "one*two*three*four*five")

-- Disable pattern match
verif("one1two22three333four4444five", "%d+", true, "one1two22three333four4444five")

-- Empty string
verif("", "%S+", false, "")

-- Empty pattern returns single entry
verif("abcdefg", "", false, "abcdefg")

-- Example: Split along whitespace
verif("one two  three   four    five", "%s+", false, "one*two*three*four*five")

return split

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