Added function lume.extend(), updated README and tests

README.md

@@ -98,6 +98,15 @@ local t = { 1, 2, 3 }
 lume.clear(t) -- `t` becomes {}
 ```
 
+### lume.extend(t, ...)
+Copies all the fields from the source tables to the table `t` and returns `t`.
+Tables are iterated in order, so the right-most table overrides existing
+fields.
+```
+local t = { a = 1, b = 2 }
+lume.extend(t, { b = 4, c = 6 }) -- `t` becomes { a = 1, b = 4, c = 6 }
+```
+
 ### lume.shuffle(t)
 Returns a shuffled copy of the array `t`.
 

lume.lua

@@ -183,6 +183,19 @@ function lume.clear(t)
 end
 
 
+function lume.extend(t, ...)
+  for i = 1, select("#", ...) do
+    local x = select(i, ...)
+    if x then
+      for k, v in pairs(x) do
+        t[k] = v
+      end
+    end
+  end
+  return t
+end
+
+
 function lume.shuffle(t)
   local rtn = {}
   for i = 1, #t do

test/test_lume.lua

@@ -145,6 +145,16 @@ tests["lume.clear"] = function()
   testeq( lume.clear(t) == t, true )
 end
 
+-- lume.extend
+tests["lume.extend"] = function()
+  local t = { a = 10, b = 20, c = 30 }
+  testeq( lume.extend(t) == t, true )
+  lume.extend(t, { d = 40 }, { e = 50 })
+  testeq( t, { a = 10, b = 20, c = 30, d = 40, e = 50 } )
+  lume.extend(t, { a = "cat", b = "dog" }, { b = "owl", c = "fox" })
+  testeq( t, { a = "cat", b = "owl", c = "fox", d = 40, e = 50 } )
+end
+
 -- lume.shuffle
 tests["lume.shuffle"] = function()
   local t = {1, 2, 3, 4, 5}