Add table manipulation helpers.

Added: string.split (usage: string.split("1-2-3", "-") => { 1, 2, 3 })
Added: table.join (alias of table.concat, for convenience)
Added: table.push (multiple element insert. usage: table.push(t, 1, 2, ...). Used extensively in optics)

Scripts/extend_table.lua

@@ -0,0 +1,38 @@
+-- Utilities for better table manipulation
+
+-- split a string into a table
+-- http://lua-users.org/wiki/SplitJoin (but with error messages)
+function string.split(self, sSeparator, nMax, bRegexp)
+	assert(sSeparator ~= '', "empty separator is not allowed.")
+	assert(nMax == nil or nMax >= 1, "max must be a positive number.")
+
+	local aRecord = {}
+
+	if self:len() > 0 then
+		local bPlain = not bRegexp
+		nMax = nMax or -1
+
+		local nField=1 nStart=1
+		local nFirst,nLast = self:find(sSeparator, nStart, bPlain)
+		while nFirst and nMax ~= 0 do
+			aRecord[nField] = self:sub(nStart, nFirst-1)
+			nField = nField+1
+			nStart = nLast+1
+			nFirst,nLast = self:find(sSeparator, nStart, bPlain)
+			nMax = nMax-1
+		end
+		aRecord[nField] = self:sub(nStart)
+	end
+
+	return aRecord
+end
+
+-- table.concat alias for convenience.
+table.join = table.concat
+
+-- insert multiple elements into a table at once
+function table.push(self, ...)
+	for _, v in ipairs({...}) do
+		table.insert(self, v)
+	end
+end