Re: LPEG bug?

[Roberto Ierusalimschy <roberto@...>]

> > The problem can be reduced to the following example:
> [...]
> > (I think there is a similar bug in repetitions, line 678, but I have to
> > recheck that.)
> 
> Hi Roberto,
> 
> Have you had a chance to follow up this and the outstanding LPEG bugs?

By follow up you mean the "similar bug in repetitions"? I checked, there
is no similar bug in repetitions.


>   - http://lua-users.org/lists/lua-l/2015-05/msg00483.html

I missed that message completely. (I mean, I did not see it.) The fix
seems trivial (again, a stupid bug):

lptree.c, in function lp_behind:

   TTree *tree;
   TTree *tree1 = getpatt(L, 1, NULL);
   int n = fixedlen(tree1);
-  luaL_argcheck(L, n > 0, 1, "pattern may not have fixed length");
+  luaL_argcheck(L, n >= 0, 1, "pattern may not have fixed length");
   luaL_argcheck(L, !hascaptures(tree1), 1, "pattern have captures");
   luaL_argcheck(L, n <= MAXBEHIND, 1, "pattern too long to look behind");
   tree = newroot1sib(L, TBehind);


>   - http://lua-users.org/lists/lua-l/2015-05/msg00410.html

That one the fix is this:

lptree.c:
 static TTree *newtree (lua_State *L, int len) {
   size_t size = (len - 1) * sizeof(TTree) + sizeof(Pattern);
   Pattern *p = (Pattern *)lua_newuserdata(L, size);
   luaL_getmetatable(L, PATTERN_T);
+  lua_pushvalue(L, -1);
+  lua_setuservalue(L, -3);
   lua_setmetatable(L, -2);
   p->code = NULL;  p->codesize = 0;
   return p->tree;

(OK, I will do a new release with these fixes...)

-- Roberto