junk/combine.c

   1 /* This should combine several functions into one, when they're already
   2  * compiled into functions. Useful when we don't have their AST, e.g.
   3  * to link several precompiled chunks into one.
   4  *
   5  * It currently doesn't work; meanwhile, one can use the original
   6  * 'luac' executable, although it doesn't handle argument passing through
   7  * "..." correctly.
   8  */
   9
  10 #include <lua.h>
  11 #include <lapi.h>
  12 #include <lfunc.h>
  13 #include <lstate.h>
  14 #include <lstring.h>
  15 #include <lopcodes.h>
  16 #include <ldo.h>
  17
  18 static int lua_combine( lua_State* L) {
  19   int n = lua_gettop( L); /* Number of functions to combine */
  20   if( 1 == n) {
  21     return 1; /* Only one function, nothing to combine */
  22   } else {
  23       int i, pc = 3*n + 1;
  24       Proto* f = luaF_newproto( L);
  25       setptvalue2s( L,L->top,f);
  26       incr_top( L);
  27       f->source       = luaS_newliteral( L,"=(combiner)");
  28       f->maxstacksize = 2;
  29       f->is_vararg    = VARARG_ISVARARG;
  30       f->code         = luaM_newvector(L, pc, Instruction);
  31       f->sizecode     = pc;
  32       f->p            = luaM_newvector( L, n, Proto*);
  33       f->sizep        = n;
  34       for( i = pc = 0; i < n; i ++) {
  35         int proto_idx = i-n-1;
  36         Proto *p      = clvalue( L->top + proto_idx)->l.p;
  37         f->p[i]       = p;
  38         f->code[pc++] = CREATE_ABx( OP_CLOSURE, 0, i);
  39         f->code[pc++] = CREATE_ABx( OP_VARARG,  1, 0);
  40         f->code[pc++] = CREATE_ABC( OP_CALL,    0, 0, 1);
  41       }
  42       f->code[pc++]   = CREATE_ABC( OP_RETURN, 0, 1, 0);
  43       return 1;
  44     }
  45 }
  46
  47 int luaopen_combine( lua_State *L) {
  48   lua_pushcfunction( L, lua_combine);
  49   lua_setglobal( L, "combine");
  50   return 0;
  51 }