Version 1.5.0

Updated tests

README.md

@@ -38,7 +38,7 @@ lume.lerp(100, 200, .5) -- Returns 150
 ```
 
 ### lume.smooth(a, b, amount)
-Similar to `lume.lerp()` but uses cosine interpolation instead of linear
+Similar to `lume.lerp()` but uses cubic interpolation instead of linear
 interpolation.
 
 ### lume.pingpong(x)
@@ -178,6 +178,20 @@ than a string. Creates and returns a new array of the given slice.
 lume.slice({"a", "b", "c", "d", "e"}, 2, 4) -- Returns {"b", "c", "d"}
 ```
 
+### lume.first(t [, n])
+Returns the first element of an array or nil if the array is empty. If `n` is
+specificed an array of the first `n` elements is returned.
+```lua
+lume.first({"a", "b", "c"}) -- Returns "a"
+```
+
+### lume.last(t [, n])
+Returns the last element of an array or nil if the array is empty. If `n` is
+specificed an array of the last `n` elements is returned.
+```lua
+lume.last({"a", "b", "c"}) -- Returns "c"
+```
+
 ### lume.invert(t)
 Returns a copy of the table where the keys have become the values and the
 values the keys.
@@ -185,6 +199,9 @@ values the keys.
 lume.invert({a = "x", b = "y"}) -- returns {x = "a", y = "b"}
 ```
 
+### lume.keys(t)
+Returns an array containing each key of the table.
+
 ### lume.clone(t)
 Returns a shallow copy of the table `t`.
 
@@ -208,6 +225,25 @@ f() -- Prints "Hello"
 f() -- Does nothing
 ```
 
+### lume.memoize(fn)
+Returns a wrapper function to `fn` where the results for any given set of
+arguments are cached. `lume.memoize()` is useful when used on functions with
+slow-running computations.
+```lua
+fib = lume.memoize(function(n) return n < 2 and n or fib(n-1) + fib(n-2) end)
+```
+
+### lume.combine(...)
+Creates a wrapper function which calls each supplied argument in the order they
+were passed to `lume.combine()`; nil arguments are ignored. The wrapper
+function passes its own arguments to each of its wrapped functions when it is
+called.
+```lua
+local f = lume.combine(function(a, b) print(a + b) end,
+                       function(a, b) print(a * b) end)
+f(3, 4) -- Prints "7" then "12" on a new line
+```
+
 ### lume.time(fn, ...)
 Inserts the arguments into function `fn` and calls it. Returns the time in
 seconds the function `fn` took to execute followed by `fn`'s returned values.
@@ -215,16 +251,6 @@ seconds the function `fn` took to execute followed by `fn`'s returned values.
 lume.time(function(x) return x end, "hello") -- Returns 0, "hello"
 ```
 
-### lume.combine(...)
-Creates a wrapper function which calls each supplied argument in the order they
-were passed to `lume.combine`. The wrapper function passes its own arguments to
-each of its wrapped functions when it is called.
-```lua
-local f = lume.combine(function(a, b) print(a + b) end,
-                       function(a, b) print(a * b) end)
-f(3, 4) -- Prints "7" then "12" on a new line
-```
-
 ### lume.lambda(str)
 Takes a string lambda and returns a function. `str` should be a list of
 comma-separated parameters, followed by `->`, followed by the expression which
@@ -324,6 +350,11 @@ lume.chain({1, 2, 3, 4})
   :map(function(x) return -x end)
   :result() -- Returns { -2, -4 }
 ```
+The table returned by the `lume` module, when called, acts in the same manner
+as calling `lume.chain()`.
+```lua
+lume({1, 2, 3}):each(print) -- Prints 1, 2 then 3 on separate lines
+```
 
 
 ## License

lume.lua

@@ -7,7 +7,7 @@
 -- under the terms of the MIT license. See LICENSE for details.
 --
 
-local lume = { _version = "1.3.1" }
+local lume = { _version = "1.5.0" }
 
 local pairs, ipairs = pairs, ipairs
 local type, assert, unpack = type, assert, unpack or table.unpack
@@ -30,7 +30,27 @@ local absindex = function(len, i)
 end
 
 local iscallable = function(x)
-  return type(x) == "function" or getmetatable(x).__call ~= nil
+  if type(x) == "function" then return true end
+  local mt = getmetatable(x)
+  return mt and mt.__call ~= nil
+end
+
+local identity = function(x)
+  return x
+end
+
+local iteratee = function(x)
+  if x == nil then return identity end
+  if iscallable(x) then return x end
+  if type(x) == "table" then
+    return function(z)
+      for k, v in pairs(x) do
+        if z[k] ~= v then return false end
+      end
+      return true
+    end
+  end
+  return function(z) return z[x] end
 end
 
 
@@ -57,7 +77,8 @@ end
 
 
 function lume.smooth(a, b, amount)
-  local m = (1 - math_cos(lume.clamp(amount, 0, 1) * math_pi)) / 2
+  local t = lume.clamp(amount, 0, 1)
+  local m = t * t * (3 - 2 * t)
   return a + (b - a) * m
 end
 
@@ -118,7 +139,7 @@ end
 
 function lume.array(...)
   local t = {}
-  for x in unpack({...}) do t[#t + 1] = x end
+  for x in ... do t[#t + 1] = x end
   return t
 end
 
@@ -134,14 +155,15 @@ end
 
 
 function lume.map(t, fn)
-  local rtn = {} 
+  fn = iteratee(fn)
+  local rtn = {}
   for k, v in pairs(t) do rtn[k] = fn(v) end
   return rtn
 end
 
 
 function lume.all(t, fn)
-  fn = fn or function(x) return x end
+  fn = iteratee(fn)
   for k, v in pairs(t) do
     if not fn(v) then return false end
   end
@@ -150,7 +172,7 @@ end
 
 
 function lume.any(t, fn)
-  fn = fn or function(x) return x end
+  fn = iteratee(fn)
   for k, v in pairs(t) do
     if fn(v) then return true end
   end
@@ -168,7 +190,7 @@ end
 
 function lume.set(t, retainkeys)
   local rtn = {}
-  for k, v in pairs(lume.invert(t)) do 
+  for k, v in pairs(lume.invert(t)) do
     rtn[retainkeys and v or (#rtn + 1)] = k
   end
   return rtn
@@ -176,6 +198,7 @@ end
 
 
 function lume.filter(t, fn, retainkeys)
+  fn = iteratee(fn)
   local rtn = {}
   for k, v in pairs(t) do
     if fn(v) then rtn[retainkeys and k or (#rtn + 1)] = v end
@@ -201,6 +224,7 @@ end
 
 
 function lume.match(t, fn)
+  fn = iteratee(fn)
   for k, v in pairs(t) do
     if fn(v) then return v, k end
   end
@@ -211,6 +235,7 @@ end
 function lume.count(t, fn)
   local count = 0
   if fn then
+    fn = iteratee(fn)
     for k, v in pairs(t) do
       if fn(v) then count = count + 1 end
     end
@@ -232,6 +257,18 @@ function lume.slice(t, i, j)
 end
 
 
+function lume.first(t, n)
+  if not n then return t[1] end
+  return lume.slice(t, 1, n)
+end
+
+
+function lume.last(t, n)
+  if not n then return t[#t] end
+  return lume.slice(t, -n, -1)
+end
+
+
 function lume.invert(t)
   local rtn = {}
   for k, v in pairs(t) do rtn[v] = k end
@@ -239,6 +276,13 @@ function lume.invert(t)
 end
 
 
+function lume.keys(t)
+  local rtn = {}
+  for k, v in pairs(t) do rtn[#rtn + 1] = k end
+  return rtn
+end
+
+
 function lume.clone(t)
   local rtn = {}
   for k, v in pairs(t) do rtn[k] = v end
@@ -251,7 +295,7 @@ function lume.fn(fn, ...)
   local args = {...}
   return function(...)
     local a = lume.merge(lume.clone(args), {...})
-    return fn(unpack(a)) 
+    return fn(unpack(a))
   end
 end
 
@@ -267,22 +311,46 @@ function lume.once(fn, ...)
 end
 
 
-function lume.time(fn, ...)
-  local start = os.clock()
-  local rtn = {fn(...)}
-  return (os.clock() - start), unpack(rtn)
+local memoize_fnkey = {}
+local memoize_nil = {}
+
+function lume.memoize(fn)
+  local cache = {}
+  return function(...)
+    local c = cache
+    for i = 1, select("#", ...) do
+      local a = select(i, ...) or memoize_nil
+      c[a] = c[a] or {}
+      c = c[a]
+    end
+    c[memoize_fnkey] = c[memoize_fnkey] or {fn(...)}
+    return unpack(c[memoize_fnkey])
+  end
 end
 
 
 function lume.combine(...)
-  local funcs = {...}
-  assert(lume.all(funcs, iscallable), "expected all arguments to be functions")
+  local funcs = {}
+  for i = 1, select("#", ...) do
+    local fn = select(i, ...)
+    if fn ~= nil then
+      assert(iscallable(fn), "expected a function or nil")
+      funcs[#funcs + 1] = fn
+    end
+  end
   return function(...)
     for _, f in ipairs(funcs) do f(...) end
   end
 end
 
 
+function lume.time(fn, ...)
+  local start = os.clock()
+  local rtn = {fn(...)}
+  return (os.clock() - start), unpack(rtn)
+end
+
+
 local lambda_cache = {}
 
 function lume.lambda(str)
@@ -337,8 +405,8 @@ end
 
 function lume.format(str, vars)
   if not vars then return str end
-  local f = function(x) 
-    return tostring(vars[x] or vars[tonumber(x)] or "{" .. x .. "}") 
+  local f = function(x)
+    return tostring(vars[x] or vars[tonumber(x)] or "{" .. x .. "}")
   end
   return (str:gsub("{(.-)}", f))
 end
@@ -375,7 +443,7 @@ function lume.hotswap(modname)
   local oldglobal = lume.clone(_G)
   local updated = {}
   local function update(old, new)
-    if updated[old] then return end 
+    if updated[old] then return end
     updated[old] = true
     local oldmt, newmt = getmetatable(old), getmetatable(new)
     if oldmt and newmt then update(oldmt, newmt) end
@@ -395,7 +463,7 @@ function lume.hotswap(modname)
     local newmod = require(modname)
     if type(oldmod) == "table" then update(oldmod, newmod) end
     for k, v in pairs(oldglobal) do
-      if v ~= _G[k] and type(v) == "table" then 
+      if v ~= _G[k] and type(v) == "table" then
         update(v, _G[k])
         _G[k] = v
       end
@@ -408,9 +476,9 @@ end
 
 
 function lume.rgba(color)
-  local a = math_floor((color / 2 ^ 24) % 256)
-  local r = math_floor((color / 2 ^ 16) % 256)
-  local g = math_floor((color / 2 ^ 08) % 256)
+  local a = math_floor((color / 16777216) % 256)
+  local r = math_floor((color /    65536) % 256)
+  local g = math_floor((color /      256) % 256)
   local b = math_floor((color) % 256)
   return r, g, b, a
 end
@@ -430,5 +498,11 @@ function lume.chain(value)
   return setmetatable({ _value = value }, chain_mt)
 end
 
+setmetatable(lume,  {
+  __call = function(t, ...)
+    return lume.chain(...)
+  end
+})
+
 
 return lume

test/test_lume.lua

@@ -141,6 +141,8 @@ end
 tests["lume.map"] = function()
   testeq( lume.map({1, 2, 3}, function(x) return x * 2 end), {2, 4, 6} )
   testeq( lume.map({a=2,b=3}, function(x) return x * 2 end), {a=4,b=6} )
+  local t = {{ id = 10 }, { id = 20 }, { id = 30 }}
+  testeq( lume.map(t, "id"), { 10, 20, 30 })
 end
 
 -- lume.all
@@ -149,6 +151,10 @@ tests["lume.all"] = function()
   testeq( lume.all({true, true, true, true}),                         true  )
   testeq( lume.all({2, 3, 4, 5}, function(x) return x % 2 == 0 end),  false )
   testeq( lume.all({2, 4, 6, 8}, function(x) return x % 2 == 0 end),  true  )
+  testeq( lume.all({{ x = 1 }, {}, { x = 3 }}, "x"),                  false )
+  testeq( lume.all({{ x = 1 }, { x = 2 }, { x = 3 }}, "x"),           true  )
+  testeq( lume.all({{ x = 1 }, { x = 2 }, { x = 3 }}, { x = 2 }),     false )
+  testeq( lume.all({{ x = 2 }, { x = 2 }, { x = 2 }}, { x = 2 }),     true  )
 end
 
 -- lume.any
@@ -157,6 +163,9 @@ tests["lume.any"] = function()
   testeq( lume.any({false, false, false}),                            false )
   testeq( lume.any({2, 3, 4, 5}, function(x) return x % 2 == 0 end),  true  )
   testeq( lume.any({1, 3, 5, 7}, function(x) return x % 2 == 0 end),  false )
+  local t = {{ id = 10 }, { id = 20 }, { id = 30 }}
+  testeq( lume.any(t, { id = 10 }), true  )
+  testeq( lume.any(t, { id = 40 }), false )
 end
 
 -- lume.reduce
@@ -189,6 +198,8 @@ tests["lume.filter"] = function()
   testeq( t, {2, 4} )
   local t = lume.filter({a=1, b=2, c=3}, function(x) return x == 2 end, true) 
   testeq( t, {b=2} )
+  local t = lume.filter({{ x=1, y=1 }, { x=2, y=2 }, { x=1, y=3 }}, { x = 1 })
+  testeq( t, {{ x=1, y=1 }, {x=1, y=3}} )
 end
 
 -- lume.merge
@@ -208,6 +219,7 @@ end
 tests["lume.match"] = function()
   local t = { "a", "b", "c", "d" }
   local t2 = { a = 1, b = 2, c = 3, d = 4 }
+  local t3 = { {x=1, y=2}, {x=3, y=4}, {x=5, y=6} }
   local v, k = lume.match(t, function(x) return x > "c" end)
   testeq( v, "d"  )
   testeq( k, 4    )
@@ -220,6 +232,8 @@ tests["lume.match"] = function()
   local v, k = lume.match(t2, function(x) return x > 5 end)
   testeq( v, nil  )
   testeq( k, nil  )
+  local v, k = lume.match(t3, { x = 3, y = 4 })
+  testeq( k, 2    )
 end
 
 -- lume.count
@@ -229,6 +243,10 @@ tests["lume.count"] = function()
   testeq( lume.count(t, function(x) return x % 2 == 0 end ), 3 )
   local a = { 5, 6, 7, 8, 9 }
   testeq( lume.count(a), #a )
+  local t = { { n = 20 }, { n = 30 }, { n = 40 }, { n = 20 } }
+  testeq( lume.count(t, { n = 20 }),  2 )
+  testeq( lume.count(t, { n = 30 }),  1 )
+  testeq( lume.count(t, { n = 50 }),  0 )
 end
 
 -- lume.slice
@@ -248,14 +266,40 @@ tests["lume.slice"] = function()
   testeq( lume.slice({"a", "b", "c", "d", "e"}, -3, 900), {"c", "d", "e"} )
 end
 
+-- lume.first
+tests["lume.first"] = function()
+  local t = { "a", "b", "c", "d", "e" }
+  testeq( lume.first(t),    "a"           )
+  testeq( lume.first(t, 1), { "a" }       )
+  testeq( lume.first(t, 2), { "a", "b" }  )  
+end
+
+-- lume.last
+tests["lume.last"] = function()
+  local t = { "a", "b", "c", "d", "e" }
+  testeq( lume.last(t),     "e"           )
+  testeq( lume.last(t, 1),  { "e" }       )
+  testeq( lume.last(t, 2),  { "d", "e" }  )  
+end
+
 -- lume.invert
-tests["lume_invert"] = function()
+tests["lume.invert"] = function()
   testeq( lume.invert({}),                        {}                  )
   testeq( lume.invert{a = "x", b = "y"},          {x = "a", y = "b"}  )
   testeq( lume.invert{a = 1, b = 2},              {"a", "b"}          )
   testeq( lume.invert(lume.invert{a = 1, b = 2}), {a = 1, b = 2}      )
 end
 
+-- lume.keys
+tests["lume.keys"] = function()
+  testeq( lume.keys({}), {} )
+  local t = lume.keys({ aaa = 1, bbb = 2, ccc = 3 }) 
+  table.sort(t)
+  testeq( t, {"aaa", "bbb", "ccc"} ) 
+  local t = lume.keys({ "x", "x", "x" })
+  testeq( t, {1, 2, 3} )
+end
+
 -- lume.clone
 tests["lume.clone"] = function()
   local t = {6, 7, 4, 5}
@@ -279,11 +323,18 @@ tests["lume.once"] = function()
   tester.test.error( lume.once, 123 )
 end
 
--- lume.time
-tests["lume.time"] = function()
-  local t, a, b, c = lume.time(function(x) return 50, 60, x end, 70)
-  testeq( type(t),    "number"      )
-  testeq( {a, b, c},  {50, 60, 70}  )
+-- lume.memoize
+tests["lume.memoize"] = function()
+  local f = lume.memoize(
+    function(a, b, c)
+      return tostring(a) .. tostring(b) .. tostring(c)
+    end)
+  testeq( f("hello", nil, 15),  "hellonil15"  )
+  testeq( f("hello", nil, 15),  "hellonil15"  )
+  testeq( f(),                  "nilnilnil"   )
+  testeq( f(),                  "nilnilnil"   )
+  local f2 = lume.memoize(function() end)
+  testeq( f2(), nil )
 end
 
 -- lume.combine
@@ -294,6 +345,17 @@ tests["lume.combine"] = function()
   local fn = lume.combine(a, b)
   fn(10, 20)
   testeq( acc, 230 )
+  acc = 0
+  fn = lume.combine(nil, a, nil, b, nil)
+  fn(10, 20)
+  testeq( acc, 230 )
+end
+
+-- lume.time
+tests["lume.time"] = function()
+  local t, a, b, c = lume.time(function(x) return 50, 60, x end, 70)
+  testeq( type(t),    "number"      )
+  testeq( {a, b, c},  {50, 60, 70}  )
 end
 
 -- lume.lambda
@@ -399,6 +461,8 @@ tests["lume.chain"] = function()
   local t = lume.chain({1, 2}):map(function(x) return x * 2 end):result() 
   testeq( t, { 2, 4 } )
   testeq( lume.chain(10):result(), 10 )
+  local t = lume({1, 2}):map(function(x) return x * 2 end):result()
+  testeq( t, { 2, 4 } )
 end