Version 1.3.0

Moved the function index() from lume.slice()'s body to local var
absindex, this improves the performance of lume.slice() on luajit
significantly and improves it to a lesser extent on non-jit lua.

README.md

@@ -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.
@@ -200,6 +215,16 @@ 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
@@ -266,6 +291,10 @@ 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 +314,17 @@ 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 = "1.3.0" }
 
 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 +19,20 @@ 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)
+  return type(x) == "function" or getmetatable(x).__call ~= nil
+end
+
 
 function lume.clamp(x, min, max)
   return x < min and min or (x > max and max or x)
@@ -193,13 +199,33 @@ 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
@@ -220,6 +246,7 @@ 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), {...})
@@ -246,6 +273,15 @@ function lume.time(fn, ...)
 end
 
 
+function lume.combine(...)
+  local funcs = {...}
+  assert(lume.all(funcs, iscallable), "expected all arguments to be functions")
+  return function(...)
+    for _, f in ipairs(funcs) do f(...) end
+  end
+end
+
+
 local lambda_cache = {}
 
 function lume.lambda(str)
@@ -308,9 +344,13 @@ end
 
 
 function lume.trace(...)
+  local function stringify(x)
+    x = (type(x) == "number") and lume.round(x, .01) or x
+    return tostring(x)
+  end
   local info = debug.getinfo(2, "Sl")
   local head = "[" .. info.short_src .. ":" .. info.currentline .. "] "
-  print(head .. table.concat(lume.map({...}, tostring), " "))
+  print(head .. table.concat(lume.map({...}, stringify), " "))
 end
 
 
@@ -319,6 +359,16 @@ 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 = {}
@@ -364,4 +414,19 @@ function lume.rgba(color)
 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 +276,7 @@ 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.time
@@ -256,6 +286,16 @@ tests["lume.time"] = function()
   testeq( {a, b, c},  {50, 60, 70}  )
 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 )
+end
+
 -- lume.lambda
 tests["lume.lambda"] = function()
   testeq( lume.lambda "x->x*x"(10),                 100         )
@@ -319,11 +359,11 @@ tests["lume.trace"] = function()
   print = function(x)
     file, line, msg = x:match("%[(.-):(.-)%] (.*)")
   end
-  lume.trace("Hi world")
+  lume.trace("Hi world", 123.456, 1)
   print = oldprint
   testeq( file:match(".lua$"),    ".lua"      )
   testeq( tonumber(line) ~= nil,  true        ) 
-  testeq( msg,                    "Hi world"  )
+  testeq( msg,                    "Hi world 123.46 1"  )
 end
 
 -- lume.dostring
@@ -332,6 +372,12 @@ 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 +394,13 @@ 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()