# HG changeset patch
# User jbe
# Date 1408530211 -7200
# Node ID 2fad7f50076bf304cee8dc421866b52495787bb7
# Parent  431fa6946a61455a2d0bd163ed256e9462e9c166
Added coroutine based filter(func, ...) example to new file seqlua_ipairs_example.lua

diff -r 431fa6946a61 -r 2fad7f50076b README
--- a/README	Wed Aug 20 06:47:14 2014 +0200
+++ b/README	Wed Aug 20 12:23:31 2014 +0200
@@ -36,12 +36,12 @@
     --  2   b
     --  3   c
 
-    function alphabet(from, to)
+    function alphabet()
       local letter = nil
       return function()
         if letter == nil then
-          letter = from
-        elseif letter == to then
+          letter = "a"
+        elseif letter == "z" then
           return nil
         else
           letter = string.char(string.byte(letter) + 1)
@@ -63,40 +63,6 @@
     --  25  y
     --  26  z
 
-    c = setmetatable(
-      { iter = alphabet("a", "f") },
-      { __call = function(t) return t.iter() end }
-    )
-
-    for i, v in ipairs(c) do
-      print(i, v)
-    end
-    -- prints:
-    --  1   a
-    --  2   b
-    --  3   c
-    --  4   d
-    --  5   e
-    --  6   f
-
-    g = coroutine.wrap(function()
-      coroutine.yield("Alice")
-      coroutine.yield("Bob")
-      for i = 1, 3 do
-        coroutine.yield("Person #" .. tostring(i))
-      end
-    end)
-
-    for i, v in ipairs(g) do
-      print(i, v)
-    end
-    -- prints:
-    --  1   Alice
-    --  2   Bob
-    --  3   Person #1
-    --  4   Person #2
-    --  5   Person #3
-
     set = {apple = true, banana = true}
     for i, k, v in ipairs(pairs(set)) do
       print(i, k, v)
@@ -106,6 +72,9 @@
     --  2   apple   true
     -- (order of "apple" and "banana" may vary)
 
+More examples for invoking the ``ipairs(...)`` function can be found in the
+file ``seqlua_ipairs_example.lua``.
+
 The function ``iterator(...)`` may be used to convert any table, any function,
 or any iterator triplet into a single function (possibly creating a closure):
 
diff -r 431fa6946a61 -r 2fad7f50076b seqlua_ipairs_example.lua
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/seqlua_ipairs_example.lua	Wed Aug 20 12:23:31 2014 +0200
@@ -0,0 +1,110 @@
+require "seqlua"
+
+t = {"a", "b", "c"}
+
+for i, v in ipairs(t) do
+  print(i, v)
+end
+-- prints:
+--  1   a
+--  2   b
+--  3   c
+
+function alphabet(from, to)
+  local letter = nil
+  return function()
+    if letter == nil then
+      letter = from
+    elseif letter == to then
+      return nil
+    else
+      letter = string.char(string.byte(letter) + 1)
+    end
+    return letter
+  end
+end
+
+f = alphabet("a", "z")
+
+for i, v in ipairs(f) do
+  print(i, v)
+end
+-- prints:
+--  1   a
+--  2   b
+--  3   c
+--  ...
+--  25  y
+--  26  z
+
+c = setmetatable(
+  { iter = alphabet("a", "f") },
+  { __call = function(t) return t.iter() end }
+)
+
+for i, v in ipairs(c) do
+  print(i, v)
+end
+-- prints:
+--  1   a
+--  2   b
+--  3   c
+--  4   d
+--  5   e
+--  6   f
+
+g = coroutine.wrap(function()
+  coroutine.yield("Alice")
+  coroutine.yield("Bob")
+  for i = 1, 3 do
+    coroutine.yield("Person #" .. tostring(i))
+  end
+end)
+
+for i, v in ipairs(g) do
+  print(i, v)
+end
+-- prints:
+--  1   Alice
+--  2   Bob
+--  3   Person #1
+--  4   Person #2
+--  5   Person #3
+
+function filter(f, iter, iter_s, iter_i)
+  return coroutine.wrap(function()
+    for i, v in ipairs(iter, iter_s, iter_i) do f(v) end
+  end)
+end
+
+function filterfunc(v)
+  local type_v = type(v)
+  if type_v == "string" then
+    coroutine.yield(v)
+  elseif type_v == "number" then
+    for i = 1, v do
+      coroutine.yield(true)
+    end
+  end
+end
+
+for v in filter(filterfunc, {"a", "b", 3, "c"}) do
+  print(v)
+end
+-- prints:
+--  a
+--  b
+--  true
+--  true
+--  true
+--  c
+
+set = {apple = true, banana = true}
+for i, k, v in ipairs(pairs(set)) do
+  print(i, k, v)
+end
+-- prints:
+--  1   banana  true
+--  2   apple   true
+-- (order of "apple" and "banana" may vary)
+