Re: table.pack()
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- Subject: Re: table.pack()
- From: David Manura <dm.lua@...>
- Date: 2010年1月26日 22:28:29 -0500
On Tue, Jan 26, 2010 at 6:42 PM, Patrick Donnelly wrote:
> I would agree that using an 'n' field is an odd about-face for Lua
> after the changes in 5.0 -> 5.1. It would be easier to just return a
> second value and allow the programmer to set his own convention.
Consider something like this patch to table.unpack:
-- test suite for patch
local function g(n) return table.unpack({0}, 1, n) end
local function f(n)
local results = {g(n)} -- note: nil's are preserved via Table
sizearray field
if results[1] then results[1] = true end -- edits allowed if does
not resize table
return table.unpack(results) -- uses sizearray, not length, by default
end
for n=1,2000 do assert(select('#', f(n)) == n, n) end
print 'OK'
diff -ur lua-5.2.0-work2/src/lapi.c lua-5.2.0-work2-patch/src/lapi.c
--- lua-5.2.0-work2/src/lapi.c
+++ lua-5.2.0-work2-patch/src/lapi.c
@@ -385,6 +385,15 @@
}
+LUA_API size_t lua_asize (lua_State *L, int idx) {
+ StkId o = index2addr(L, idx);
+ switch (ttype(o)) {
+ case LUA_TTABLE: return hvalue(o)->sizearray;
+ default: return 0;
+ }
+}
+
+
LUA_API lua_CFunction lua_tocfunction (lua_State *L, int idx) {
StkId o = index2addr(L, idx);
return (!iscfunction(o)) ? NULL : clvalue(o)->c.f;
diff -ur lua-5.2.0-work2/src/ltable.c lua-5.2.0-work2-patch/src/ltable.c
--- lua-5.2.0-work2/src/ltable.c
+++ lua-5.2.0-work2-patch/src/ltable.c
@@ -32,7 +32,7 @@
#include "lobject.h"
#include "lstate.h"
#include "ltable.h"
-
+#include <stdio.h> /*DEBUG*/
/*
** max size of array part is 2^MAXBITS
@@ -266,6 +266,7 @@
luaM_reallocvector(L, t->array, t->sizearray, size, TValue);
for (i=t->sizearray; i<size; i++)
setnilvalue(&t->array[i]);
+ printf("DEBUG:[setarrayvector:%d->%d]\n", t->sizearray, size);
t->sizearray = size;
}
@@ -306,6 +307,7 @@
setnodevector(L, t, nhsize);
if (nasize < oldasize) { /* array part must shrink? */
t->sizearray = nasize;
+ printf("DEBUG:[luaH_resize:%d]\n", nasize);
/* re-insert elements from vanishing slice */
for (i=nasize; i<oldasize; i++) {
if (!ttisnil(&t->array[i]))
diff -ur lua-5.2.0-work2/src/ltablib.c lua-5.2.0-work2-patch/src/ltablib.c
--- lua-5.2.0-work2/src/ltablib.c 2010年01月13日 14:59:10.000000000 -0500
+++ lua-5.2.0-work2-patch/src/ltablib.c 2010年01月26日 21:27:29.875000000 -0500
@@ -188,7 +188,7 @@
int i, e, n;
luaL_checktype(L, 1, LUA_TTABLE);
i = luaL_optint(L, 2, 1);
- e = luaL_opt(L, luaL_checkint, 3, (int)lua_rawlen(L, 1));
+ e = luaL_opt(L, luaL_checkint, 3, (int)lua_asize(L, 1));
if (i > e) return 0; /* empty range */
n = e - i + 1; /* number of elements */
if (n <= 0 || !lua_checkstack(L, n)) /* n <= 0 means arith. overflow */
diff -ur lua-5.2.0-work2/src/lua.h lua-5.2.0-work2-patch/src/lua.h
--- lua-5.2.0-work2/src/lua.h 2010年01月13日 20:40:04.000000000 -0500
+++ lua-5.2.0-work2-patch/src/lua.h 2010年01月26日 22:06:51.578125000 -0500
@@ -157,6 +157,7 @@
LUA_API int (lua_toboolean) (lua_State *L, int idx);
LUA_API const char *(lua_tolstring) (lua_State *L, int idx, size_t *len);
LUA_API size_t (lua_rawlen) (lua_State *L, int idx);
+LUA_API size_t (lua_asize) (lua_State *L, int idx);
LUA_API lua_CFunction (lua_tocfunction) (lua_State *L, int idx);
LUA_API void *(lua_touserdata) (lua_State *L, int idx);
LUA_API lua_State *(lua_tothread) (lua_State *L, int idx);