Squirrel: pitfalls & how2s

[griffin71]

I wonder if any of us programmers knows if or how it is possible to pass a variable argument list as an argument. The SQ ref. man. sais nothing explicit about that. It does say, however, that

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Myfunc1(arg1, arg2, ...) {
    Myfunc2(arg1, vargv)
    .
    .
    .
}

MyFunc2(arg1, ...) {
    .
    .
    .
}

won't work.

Any suggestions?

Whenever you make the variable arguments explicit, things do work, as in

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Myfunc1(arg1, arg2, ...) {
    Myfunc2(arg1, vargv[0])
    .
    .
    .
}

I suppose this does work, because vargv[0] copies the first vararg, which then no longer is a pseudo argument.

[DaleStan]

Does squirrel provide a va_list[0] type? If so, pass it as a single argument. If not, you'll have to muster up some other trick, which probably won't be the easiest thing in the world. For hints as to the presence of this type, look for equivalents to the vprintf class[1] of functions:

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printf(const char*, ...);
vprintf(const char*, va_list);

[0] (not an array index)
Akin to the C:

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void Func2(va_list ap) {
 //...
}

void Func1(int arg1, ...) {
  va_list ap;
  va_start(arg1, ap);
  Func2(ap);
  //...
}

[1] vprintf, vsprintf, vfprintf, vscanf, vsscanf, and vfscanf are the six in C that come to mind.

[benc]

AFAIK, there is no syntax in Squirrel to easily pass vargv from one function to the next. I'm no Squirrel guru though; you might try your question/feature request at http://squirrel-lang.org/forums/

Ugly, stupid hacks are always possible, though:

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function call(f, v)
{
  switch (v.len()) {
    case 0: return f();
    case 1: return f(v[0]);
    case 2: return f(v[0], v[1]);
    case 3: return f(v[0], v[1], v[2]);
    case 4: return f(v[0], v[1], v[2], v[3]);
    case 5: return f(v[0], v[1], v[2], v[3], v[4]);
    case 6: return f(v[0], v[1], v[2], v[3], v[4], v[5]);
    case 7: return f(v[0], v[1], v[2], v[3], v[4], v[5], v[6]);
    case 8: return f(v[0], v[1], v[2], v[3], v[4], v[5], v[6], v[7]);
    case 9: return f(v[0], v[1], v[2], v[3], v[4], v[5], v[6], v[7], v[8]);
  }
  throw "too many arguments";
}

function sum(...)
{
  local total = 0;
  for (local i = 0; i < vargc; i++)
    total += vargv[i];
  return total;
}

function my_sum(dummy, ...)
{
  local v = [];
  for (local i = 0; i < vargc; i++)
    v.append(vargv[i]);
  return call(sum, v);
}

print(my_sum("blah", 1, 2, 3, 4));
// output: 10

[TheJosh]

just make the function take a single argument: an array

then your 'arguments' can be whatever length you want