# HG changeset patch
# User jbe
# Date 1408649521 -7200
# Node ID 44880bcfc3237b1f88aad24dc67e8fcad53a6600
# Parent  28d472cc7a9b2d9b1d9d01e4cecda559d6cc15f0
Macro seqlua_iterloop doesn't automatically pop the value anymore (use seqlua_iterloopauto instead); New function string.concat(sep, seq) introduced

diff -r 28d472cc7a9b -r 44880bcfc323 Makefile
--- a/Makefile	Thu Aug 21 20:20:20 2014 +0200
+++ b/Makefile	Thu Aug 21 21:32:01 2014 +0200
@@ -8,8 +8,8 @@
 seqlualib.o: seqlualib.c seqlualib.h
 	cc -O2 -c -fpic -I $(LUA_INCLUDE) -o seqlualib.o seqlualib.c
 
-seqlua.so: seqlua.o
-	ld -shared -o seqlua.so seqlua.o
+seqlua.so: seqlua.o seqlualib.o
+	ld -shared -o seqlua.so seqlua.o seqlualib.o
 
 seqlua.o: seqlua.c seqlualib.h
 	cc -O2 -c -fpic -I $(LUA_INCLUDE) -o seqlua.o seqlua.c
diff -r 28d472cc7a9b -r 44880bcfc323 README
--- a/README	Thu Aug 21 20:20:20 2014 +0200
+++ b/README	Thu Aug 21 21:32:01 2014 +0200
@@ -3,10 +3,18 @@
 
 This is an experimental package to extend Lua in the following manner:
 
-* allow ipairs(...) to accept tables as well as functions
+* allow ``ipairs(seq)`` to accept tables as well as functions,
+* add a new function ``string.concat(separator, seq)`` to concat either table
+  entries or function return values,
 * provide auxiliary C functions and macros to simplify iterating over both
   tables and iterator functions with the same statement.
 
+In other words:
+When calling ``ipairs(seq)`` or ``string.concat(separator, seq)``,
+then ``seq`` may either be a (table) sequence or a (function) iterator.
+Auxiliary C functions and macros are provided to simplify extending your own
+C functions in the same manner.
+
 This library completely ignores the ``__ipairs`` metamethod (as it is
 deprecated since Lua 5.3.0-alpha). It respects, however, any ``__index`` and
 ``__call`` metamethods (this may cause unexpected behavior when passing
@@ -18,7 +26,8 @@
 Lua part of the library
 -----------------------
 
-The new ``ipairs(...)`` function works as follows:
+The modified ``ipairs(seq)`` function and the new ``string.concat`` function
+work as demonstrated in the following examples:
 
     require "seqlua"
 
@@ -32,6 +41,9 @@
     --  2   b
     --  3   c
 
+    print(string.concat(",", t))
+    -- prints: a,b,c
+
     function alphabet()
       local letter = nil
       return function()
@@ -57,6 +69,9 @@
     --  25  y
     --  26  z
 
+    print(string.concat(",", alphabet()))
+    -- prints: a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z
+
     function filter(f, seq)
       return coroutine.wrap(function()
         for i, v in ipairs(seq) do f(v) end
@@ -85,6 +100,9 @@
     --  true
     --  c
 
+    print((","):concat(filter(filterfunc, {"a", "b", 3, "c"})))
+    -- prints: a,b,true,true,true,c
+
 
 C part of the library
 ---------------------
@@ -95,6 +113,14 @@
       for ( \
         seqlua_iterinit((L), (iter), (idx)); \
         seqlua_iternext(iter); \
+      )
+
+and
+
+    #define seqlua_iterloopauto(L, iter, idx) \
+      for ( \
+        seqlua_iterinit((L), (iter), (idx)); \
+        seqlua_iternext(iter); \
         lua_pop((L), 1) \
       )
 
@@ -106,7 +132,9 @@
       seqlua_iterloop(L, &iter, 1) {
         if (seqlua_itercount(&iter) > 1) fputs(",", stdout);
         fputs(luaL_tolstring(L, -1, NULL), stdout);
-        lua_pop(L, 1);  // pops value that luaL_tolstring pushed onto stack
+        // two values need to be popped (the value pushed by
+        // seqlua_iternext and the value pushed by luaL_tolstring)
+        lua_pop(L, 2);
       }
       fputs("\n", stdout);
       return 0;
diff -r 28d472cc7a9b -r 44880bcfc323 seqlua.c
--- a/seqlua.c	Thu Aug 21 20:20:20 2014 +0200
+++ b/seqlua.c	Thu Aug 21 21:32:01 2014 +0200
@@ -1,5 +1,6 @@
 #include <lua.h>
 #include <lauxlib.h>
+#include "seqlualib.h"
 
 static int seqlua_ipairsaux_raw(lua_State *L) {
   lua_Integer i;
@@ -51,8 +52,30 @@
   return 3;
 }
 
+static int seqlua_concat(lua_State *L) {
+  const char *sep;
+  size_t seplen;
+  luaL_Buffer buf;
+  seqlua_Iterator iter;
+  sep = luaL_checklstring(L, 1, &seplen);
+  luaL_checkany(L, 2);
+  lua_settop(L, 3);
+  luaL_buffinit(L, &buf);
+  seqlua_iterloop(L, &iter, 2) {
+    lua_replace(L, 3);
+    if (seqlua_itercount(&iter) > 1) luaL_addlstring(&buf, sep, seplen);
+    luaL_tolstring(L, 3, NULL);
+    luaL_addvalue(&buf);
+  }
+  luaL_pushresult(&buf);
+  return 1;
+}
+
 int luaopen_seqlua(lua_State *L) {
   lua_pushcfunction(L, seqlua_ipairs);
   lua_setglobal(L, "ipairs");
-  return 1;
+  lua_getglobal(L, "string");
+  lua_pushcfunction(L, seqlua_concat);
+  lua_setfield(L, -2, "concat");
+  return 0;
 }
diff -r 28d472cc7a9b -r 44880bcfc323 seqlua_c_example.c
--- a/seqlua_c_example.c	Thu Aug 21 20:20:20 2014 +0200
+++ b/seqlua_c_example.c	Thu Aug 21 21:32:01 2014 +0200
@@ -3,12 +3,14 @@
 #include "seqlualib.h"
 #include <stdio.h>
 
-static int seqlua_c_example_printcsv(lua_State *L) {
+int seqlua_c_example_printcsv(lua_State *L) {
   seqlua_Iterator iter;
   seqlua_iterloop(L, &iter, 1) {
     if (seqlua_itercount(&iter) > 1) fputs(",", stdout);
     fputs(luaL_tolstring(L, -1, NULL), stdout);
-    lua_pop(L, 1);  // pop value that luaL_tolstring pushed onto stack
+    // two values need to be popped (the value pushed by
+    // seqlua_iternext and the value pushed by luaL_tolstring)
+    lua_pop(L, 2);
   }
   fputs("\n", stdout);
   return 0;
diff -r 28d472cc7a9b -r 44880bcfc323 seqlualib.h
--- a/seqlualib.h	Thu Aug 21 20:20:20 2014 +0200
+++ b/seqlualib.h	Thu Aug 21 21:32:01 2014 +0200
@@ -16,6 +16,12 @@
   for ( \
     seqlua_iterinit((L), (iter), (idx)); \
     seqlua_iternext(iter); \
+  )
+
+#define seqlua_iterloopauto(L, iter, idx) \
+  for ( \
+    seqlua_iterinit((L), (iter), (idx)); \
+    seqlua_iternext(iter); \
     lua_pop((L), 1) \
   )