Version 1.4.0

Stripped all trailing whitespace, changed ease function, and pre-computed po2

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)
@@ -156,6 +156,21 @@ exist in the table.
 lume.find({"a", "b", "c"}, "b") -- Returns 2
 ```
 
+### lume.match(t, fn)
+Returns the value and key of the value in table `t` which returns true when
+`fn` is called on it. Returns `nil` if no such value exists.
+```lua
+lume.match({1, 5, 8, 7}, function(x) return x % 2 == 0 end) -- Returns 8, 3
+```
+
+### lume.count(t [, fn])
+Counts the number of values in the table `t`. If a `fn` function is supplied it
+is called on each value, the number of times it returns true is counted.
+```lua
+lume.count({a = 2, b = 3, c = 4, d = 5}) -- Returns 4
+lume.count({1, 2, 4, 6}, function(x) return x % 2 == 0 end) -- Returns 3
+```
+
 ### lume.slice(t [, i [, j]])
 Mimics the behaviour of Lua's `string.sub`, but operates on an array rather
 than a string. Creates and returns a new array of the given slice.
@@ -193,6 +208,25 @@ 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.
@@ -266,6 +300,10 @@ Executes the lua code inside `str`.
 lume.dostring("print('Hello!')") -- Prints "Hello!"
 ```
 
+### lume.uuid()
+Generates a random UUID string; version 4 as specified in
+[RFC 4122](http://www.ietf.org/rfc/rfc4122.txt).
+
 ### lume.hotswap(modname)
 Reloads an already loaded module in place, allowing you to immediately see the
 effects of code changes without having to restart the program. `modname` should
@@ -285,6 +323,17 @@ arguments to [LÖVE](http://love2d.org)'s setColor() function.
 lume.rgba(0xFF304050) -- Returns 48, 64, 80, 255
 ```
 
+### lume.chain(value)
+Returns a wrapped object which allows chaining of lume functions. The function
+result() should be called at the end of the chain to return the resulting
+value.
+```lua
+lume.chain({1, 2, 3, 4})
+  :filter(function(x) return x % 2 == 0 end)
+  :map(function(x) return -x end)
+  :result() -- Returns { -2, -4 }
+```
+
 
 ## License
 

lume.lua

@@ -7,10 +7,10 @@
 -- under the terms of the MIT license. See LICENSE for details.
 --
 
-local lume = { _version = "1.2.1" }
+local lume = { _version = "1.4.0" }
 
 local pairs, ipairs = pairs, ipairs
-local type, assert, unpack = type, assert, unpack 
+local type, assert, unpack = type, assert, unpack or table.unpack
 local tostring, tonumber = tostring, tonumber
 local math_floor = math.floor
 local math_ceil = math.ceil
@@ -19,14 +19,23 @@ local math_cos = math.cos
 local math_atan2 = math.atan2
 local math_sqrt = math.sqrt
 local math_abs = math.abs
-local math_min = math.min
-local math_max = math.max
 local math_pi = math.pi
 
 local patternescape = function(str)
   return str:gsub("[%(%)%.%%%+%-%*%?%[%]%^%$]", "%%%1")
 end
 
+local absindex = function(len, i)
+  return i < 0 and (len + i + 1) or i
+end
+
+local iscallable = function(x)
+  if type(x) == "function" then return true end
+  local mt = getmetatable(x)
+  return mt and mt.__call ~= nil
+end
+
+
 
 function lume.clamp(x, min, max)
   return x < min and min or (x > max and max or x)
@@ -50,7 +59,8 @@ 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
 
@@ -127,7 +137,7 @@ end
 
 
 function lume.map(t, fn)
-  local rtn = {} 
+  local rtn = {}
   for k, v in pairs(t) do rtn[k] = fn(v) end
   return rtn
 end
@@ -161,7 +171,7 @@ 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
@@ -193,13 +203,33 @@ function lume.find(t, value)
 end
 
 
+function lume.match(t, fn)
+  for k, v in pairs(t) do
+    if fn(v) then return v, k end
+  end
+  return nil
+end
+
+
+function lume.count(t, fn)
+  local count = 0
+  if fn then
+    for k, v in pairs(t) do
+      if fn(v) then count = count + 1 end
+    end
+  else
+    for k in pairs(t) do count = count + 1 end
+  end
+  return count
+end
+
+
 function lume.slice(t, i, j)
-  local function index(x) return x < 0 and (#t + x + 1) or x end
-  i = i and index(i) or 1
-  j = j and index(j) or #t
+  i = i and absindex(#t, i) or 1
+  j = j and absindex(#t, j) or #t
   local rtn = {}
-  for i = math_max(i, 1), math_min(j, #t) do
-    rtn[#rtn + 1] = t[i]
+  for x = i < 1 and 1 or i, j > #t and #t or j do
+    rtn[#rtn + 1] = t[x]
   end
   return rtn
 end
@@ -220,10 +250,11 @@ end
 
 
 function lume.fn(fn, ...)
+  assert(iscallable(fn), "expected a function as the first argument")
   local args = {...}
   return function(...)
     local a = lume.merge(lume.clone(args), {...})
-    return fn(unpack(a)) 
+    return fn(unpack(a))
   end
 end
 
@@ -239,6 +270,39 @@ function lume.once(fn, ...)
 end
 
 
+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 = {}
+  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(...)}
@@ -300,8 +364,8 @@ 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
@@ -309,8 +373,13 @@ end
 
 function lume.trace(...)
   local info = debug.getinfo(2, "Sl")
-  local head = "[" .. info.short_src .. ":" .. info.currentline .. "] "
-  print(head .. table.concat(lume.map({...}, tostring), " "))
+  local t = { "[" .. info.short_src .. ":" .. info.currentline .. "]" }
+  for i = 1, select("#", ...) do
+    local x = select(i, ...)
+    x = (type(x) == "number") and lume.round(x, .01) or (x or "nil")
+    t[#t + 1] = tostring(x)
+  end
+  print(table.concat(t, " "))
 end
 
 
@@ -319,11 +388,21 @@ function lume.dostring(str)
 end
 
 
+function lume.uuid()
+  local fn = function(x)
+    local r = math_random(16) - 1
+    r = (x == "x") and (r + 1) or (r % 4) + 9
+    return ("0123456789abcdef"):sub(r, r)
+  end
+  return (("xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx"):gsub("[xy]", fn))
+end
+
+
 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
@@ -343,7 +422,7 @@ 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
@@ -356,12 +435,27 @@ 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
 
 
+local chain_mt = {}
+chain_mt.__index = lume.map(lume.filter(lume, iscallable, true),
+  function(fn)
+    return function(self, ...)
+      self._value = fn(self._value, ...)
+      return self
+    end
+  end)
+chain_mt.__index.result = function(x) return x._value end
+
+function lume.chain(value)
+  return setmetatable({ _value = value }, chain_mt)
+end
+
+
 return lume

test/test_lume.lua

@@ -204,6 +204,33 @@ tests["lume.find"] = function()
   testeq( lume.find({a=1, b=5, c=7}, 5),    "b" )
 end
 
+-- lume.match
+tests["lume.match"] = function()
+  local t = { "a", "b", "c", "d" }
+  local t2 = { a = 1, b = 2, c = 3, d = 4 }
+  local v, k = lume.match(t, function(x) return x > "c" end)
+  testeq( v, "d"  )
+  testeq( k, 4    )
+  local v, k = lume.match(t, function(x) return x < "b" end)
+  testeq( v, "a"  )
+  testeq( k, 1    )
+  local v, k = lume.match(t2, function(x) return x < 2 end)
+  testeq( v, 1    )
+  testeq( k, "a"  )
+  local v, k = lume.match(t2, function(x) return x > 5 end)
+  testeq( v, nil  )
+  testeq( k, nil  )
+end
+
+-- lume.count
+tests["lume.count"] = function()
+  local t = { a = 1, b = 2, c = 5, [13] = 22, z = 8 }
+  testeq( lume.count(t), 5 )
+  testeq( lume.count(t, function(x) return x % 2 == 0 end ), 3 )
+  local a = { 5, 6, 7, 8, 9 }
+  testeq( lume.count(a), #a )
+end
+
 -- lume.slice
 tests["lume.slice"] = function()
   testeq( lume.slice({"a", "b", "c", "d", "e"}, 2, 4),    {"b", "c", "d"} )
@@ -218,6 +245,7 @@ tests["lume.slice"] = function()
   testeq( lume.slice({"a", "b", "c", "d", "e"}, 0, 1),    {"a"}           )
   testeq( lume.slice({"a", "b", "c", "d", "e"}, 0, 0),    {}              )
   testeq( lume.slice({"a", "b", "c", "d", "e"}, -3),      {"c", "d", "e"} )
+  testeq( lume.slice({"a", "b", "c", "d", "e"}, -3, 900), {"c", "d", "e"} )
 end
 
 -- lume.invert
@@ -240,6 +268,7 @@ end
 tests["lume.fn"] = function()
   local f = lume.fn(function(a, b) return a + b end, 10)
   testeq( f(5),  15 )
+  tester.test.error( lume.fn, 123 )
 end
 
 -- lume.once
@@ -247,6 +276,35 @@ tests["lume.once"] = function()
   local f = lume.once(function(a, b) return a + b end, 10)
   testeq( f(5),  15   )
   testeq( f(5),  nil  )
+  tester.test.error( lume.once, 123 )
+end
+
+-- 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
+tests["lume.combine"] = function()
+  local acc = 0
+  local a = function(x, y) acc = acc + x + y end
+  local b = function(x, y) acc = acc + x * y end
+  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
@@ -319,11 +377,11 @@ tests["lume.trace"] = function()
   print = function(x)
     file, line, msg = x:match("%[(.-):(.-)%] (.*)")
   end
-  lume.trace("Hi world")
+  lume.trace("Hi world", 123.456, 1, nil)
   print = oldprint
-  testeq( file:match(".lua$"),    ".lua"      )
-  testeq( tonumber(line) ~= nil,  true        ) 
-  testeq( msg,                    "Hi world"  )
+  testeq( file:match(".lua$"),    ".lua"                  )
+  testeq( tonumber(line) ~= nil,  true                    ) 
+  testeq( msg,                    "Hi world 123.46 1 nil" )
 end
 
 -- lume.dostring
@@ -332,6 +390,12 @@ tests["lume.dostring"] = function()
   testeq( lume.dostring([[return 12345]]),    12345     )   
 end
 
+-- lume.uuid
+tests["lume.uuid"] = function()
+  testeq( type(lume.uuid()), "string" )
+  testeq( #lume.uuid(),      36       )
+end
+
 -- lume.hotswap
 tests["lume.hotswap"] = function()
   local ok, err = lume.hotswap("bad_module_name")
@@ -348,6 +412,13 @@ tests["lume.rgba"] = function()
   testeq( b, 0x78 )
 end
 
+-- lume.chain
+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 )
+end
+
 
 tester.dotests(tests)
 tester.test.global()