# HG changeset patch
# User jbe
# Date 1408509198 -7200
# Node ID a95fbd16473fc2632711c86830fcbe15b094e941
# Parent  03ed3361f3327ed0b429e8ccf89bc73e618e348e
Removed unnecessary creation of closures for callable values (through __call)

diff -r 03ed3361f332 -r a95fbd16473f README
--- a/README	Wed Aug 20 06:08:03 2014 +0200
+++ b/README	Wed Aug 20 06:33:18 2014 +0200
@@ -171,15 +171,11 @@
     printcsv(assert(io.open("testfile")):lines())
     -- prints: line1,line2,... of "testfile"
 
-NOTE: ``seqlua_iterinit`` will store one extra element on the stack during
-iteration. When ``seqlua_iternext`` returns 0, this extra element is popped
-from the stack automatically.
-
 Additionally, ``seqlualib`` includes a function ``seqlua_iterclosure(L, idx)``,
 which converts a table at a given stack index into a function closure (stored
 on the same stack index) that iterates over the elements of the table. If the
-value at the given stack index is already a function, it leaves the value
-unchanged. If the value is convertible to a function using ``__call,`` then the
-value is replaced by a closure calling the ``__call`` metamethod.
+value at the given stack index is already a function (or if it is callable
+through a ``__call`` metamethod), then ``seqlua_iterclosure(L, idx)`` leaves
+the value at ``idx`` unchanged.
 
 
diff -r 03ed3361f332 -r a95fbd16473f seqlua.c
--- a/seqlua.c	Wed Aug 20 06:08:03 2014 +0200
+++ b/seqlua.c	Wed Aug 20 06:33:18 2014 +0200
@@ -1,13 +1,6 @@
 #include <lua.h>
 #include <lauxlib.h>
 
-static int seqlua_aux_call(lua_State *L) {  // TODO: avoid
-  lua_pushvalue(L, lua_upvalueindex(1));
-  lua_pushvalue(L, lua_upvalueindex(2));
-  lua_call(L, 1, 1);
-  return 1;
-}
-
 static int seqlua_ipairsaux_raw(lua_State *L) {
   lua_Integer i;
   luaL_checktype(L, 1, LUA_TTABLE);
@@ -27,7 +20,7 @@
 }
 
 static int seqlua_ipairsaux_func(lua_State *L) {
-  luaL_checktype(L, 1, LUA_TFUNCTION);
+  //luaL_checktype(L, 1, LUA_TFUNCTION);
   lua_pushinteger(L, luaL_checkinteger(L, 2) + 1);
   lua_insert(L, 1);
   lua_settop(L, 2);
@@ -74,10 +67,7 @@
     }
     lua_pushcfunction(L, seqlua_ipairsaux_func);
   } else if (luaL_getmetafield(L, 1, "__call")) {
-    if (lua_type(L, -1) != LUA_TFUNCTION) luaL_error(L, "__call is not a function");
-    lua_pushvalue(L, 1);
-    lua_pushcclosure(L, seqlua_aux_call, 2);
-    lua_replace(L, 1);
+    lua_pop(L, 1);
     goto seqlua_ipairs_function;
   } else if (luaL_getmetafield(L, 1, "__index")) {
     lua_pushcfunction(L, seqlua_ipairsaux_meta);
@@ -135,10 +125,7 @@
       lua_pushcclosure(L, seqlua_iteratoraux_triplet, 3);
     }
   } else if (luaL_getmetafield(L, 1, "__call")) {
-    if (lua_type(L, -1) != LUA_TFUNCTION) luaL_error(L, "__call is not a function");
-    lua_pushvalue(L, 1);
-    lua_pushcclosure(L, seqlua_aux_call, 2);
-    lua_replace(L, 1);
+    lua_pop(L, 1);
     goto seqlua_iterator_function;
   } else if (luaL_getmetafield(L, 1, "__index")) {
     lua_pushvalue(L, 1);
diff -r 03ed3361f332 -r a95fbd16473f seqlualib.c
--- a/seqlualib.c	Wed Aug 20 06:08:03 2014 +0200
+++ b/seqlualib.c	Wed Aug 20 06:33:18 2014 +0200
@@ -2,33 +2,25 @@
 #include <lauxlib.h>
 #include "seqlualib.h"
 
-#define SEQLUA_ITERTYPE_CALL 1
-#define SEQLUA_ITERTYPE_FUNC 2
-#define SEQLUA_ITERTYPE_META 3
-#define SEQLUA_ITERTYPE_RAW  4
+#define SEQLUA_ITERTYPE_FUNC 1
+#define SEQLUA_ITERTYPE_META 2
+#define SEQLUA_ITERTYPE_RAW  3
 
 void seqlua_iterinit(lua_State *L, seqlua_Iterator *iter, int idx) {
   luaL_checkany(L, idx);  // provides better error message
   iter->L = L;
-  if (luaL_getmetafield(L, idx, "__call")) {
-    if (lua_type(L, -1) != LUA_TFUNCTION) luaL_error(L, "__call is not a function");
-    iter->idx = lua_gettop(L);
-    iter->callargidx = idx;
-    iter->itertype = SEQLUA_ITERTYPE_CALL;
-  } else if (lua_type(L, idx) == LUA_TFUNCTION) {
-    lua_pushnil(L);  // dummy value
-    iter->idx = idx;
+  iter->idx = idx;
+  if (lua_type(L, idx) == LUA_TFUNCTION) {
     iter->itertype = SEQLUA_ITERTYPE_FUNC;
+  } else if (luaL_getmetafield(L, idx, "__call")) {
+    lua_pop(L, 1);
+    iter->itertype = SEQLUA_ITERTYPE_FUNC;
+  } else if (luaL_getmetafield(L, idx, "__index")) {
+    lua_pop(L, 1);
+    iter->itertype = SEQLUA_ITERTYPE_META;
   } else {
-    iter->idx = idx;
-    if (luaL_getmetafield(L, idx, "__index")) {
-      iter->itertype = SEQLUA_ITERTYPE_META;
-      // leave __index as dummy value
-    } else {
-      lua_pushnil(L);  // dummy value
-      luaL_checktype(L, idx, LUA_TTABLE);
-      iter->itertype = SEQLUA_ITERTYPE_RAW;
-    }
+    luaL_checktype(L, idx, LUA_TTABLE);
+    iter->itertype = SEQLUA_ITERTYPE_RAW;
   }
   iter->i = 0;
 }
@@ -37,11 +29,6 @@
   lua_State *L = iter->L;
   lua_Integer i = ++iter->i;
   switch (iter->itertype) {
-  case SEQLUA_ITERTYPE_CALL:
-    lua_pushvalue(L, iter->idx);
-    lua_pushvalue(L, iter->callargidx);
-    lua_call(L, 1, 1);
-    break;
   case SEQLUA_ITERTYPE_FUNC:
     lua_pushvalue(L, iter->idx);
     lua_call(L, 0, 1);
@@ -55,7 +42,7 @@
     break;
   }
   if (lua_isnil(L, -1)) {
-    lua_pop(L, 2);  // remove nil and dummy value
+    lua_pop(L, 1);
     return 0;
   }
   return 1;
@@ -80,22 +67,12 @@
   return 1;
 }
 
-static int seqlua_iterclosureaux_call(lua_State *L) {
-  lua_pushvalue(L, lua_upvalueindex(1));
-  lua_pushvalue(L, lua_upvalueindex(2));
-  lua_call(L, 1, 1);
-  return 1;
-}
-
 void seqlua_iterclosure(lua_State *L, int idx) {
   luaL_checkany(L, idx);  // provides better error message
   if (lua_type(L, idx) == LUA_TFUNCTION) {
     // do nothing
   } else if (luaL_getmetafield(L, idx, "__call")) {
-    if (lua_type(L, -1) != LUA_TFUNCTION) luaL_error(L, "__call is not a function");
-    lua_pushvalue(L, idx);
-    lua_pushcclosure(L, seqlua_iterclosureaux_call, 2);
-    lua_replace(L, idx);
+    lua_pop(L, 1);
   } else if (luaL_getmetafield(L, idx, "__index")) {
     lua_pop(L, 1);
     lua_pushvalue(L, idx);
diff -r 03ed3361f332 -r a95fbd16473f seqlualib.h
--- a/seqlualib.h	Wed Aug 20 06:08:03 2014 +0200
+++ b/seqlualib.h	Wed Aug 20 06:33:18 2014 +0200
@@ -4,7 +4,6 @@
 typedef struct {
   lua_State *L;
   int idx;
-  int callargidx;
   int itertype;
   lua_Integer i;
 } seqlua_Iterator;