• =?iso-8859-1?Q?Robert_M._M=FCnch?= (12/12) Apr 28 2015 Hi, I have the following "problem": I have the parameters for a
• Adam D. Ruppe (13/13) Apr 28 2015 Easiest is to just do it by hand:
• =?iso-8859-1?Q?Robert_M._M=FCnch?= (7/23) Apr 28 2015 Yep, that's what I did. Really cool...
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (16/24) Apr 28 2015 import std.stdio;

=?iso-8859-1?Q?Robert_M._M=FCnch?= <robert.muench saphirion.com> writes:

Hi, I have the following "problem": I have the parameters for a 
function in an array. Now I want to call a function with a specific 
arity and use the parameters from the array to call it.

Like this pseudo-code:

args = [10, 20];

def foo(a, b): return a + b;

print(foo(*args));

Is something like this possible in D?

-- 
Robert M. Münch
http://www.saphirion.com
smarter | better | faster

"Adam D. Ruppe" <destructionator gmail.com> writes:

Easiest is to just do it by hand:

foo(args[0], args[1]);

This can also be automated with a bit of code in a lot of cases:

import std.traits;

ParameterTypeTuple!foo params;
foreach(index, ref param; params) {
     params[index] = args[index];
}

foo(params);


Move that into a helper function and you can call it apply.

You could also make that assignment in the loop to type 
conversion if you wanted, my jsvar.d does this to provide 
javascript-style functions with an apply method.

=?iso-8859-1?Q?Robert_M._M=FCnch?= <robert.muench saphirion.com> writes:

On 2015-04-28 17:52:57 +0000, Adam D. Ruppe said:

 This can also be automated with a bit of code in a lot of cases:
 
 import std.traits;
 
 ParameterTypeTuple!foo params;
 foreach(index, ref param; params) {
      params[index] = args[index];
 }
 
 foo(params);
 
 
 Move that into a helper function and you can call it apply.

Adam, thanks a lot! That's what I need. Great stuff.

 You could also make that assignment in the loop to type conversion if 
 you wanted, my jsvar.d does this to provide javascript-style functions 
 with an apply method.

Yep, that's what I did. Really cool...

-- 
Robert M. Münch
http://www.saphirion.com
smarter | better | faster

=?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:

On 04/28/2015 10:48 AM, Robert M. Münch wrote:
 Hi, I have the following "problem": I have the parameters for a function
 in an array. Now I want to call a function with a specific arity and use
 the parameters from the array to call it.

 Like this pseudo-code:

 args = [10, 20];

 def foo(a, b): return a + b;

 print(foo(*args));

 Is something like this possible in D?

import std.stdio;
import std.typetuple;

void foo(int i, string s, double d)
{
     writefln("foo: %s %s %s", i, s, d);
}

void main()
{
     auto args = TypeTuple!(42, "hello", 1.5);
     ++args[0];
     args[1] ~= " world";
     args[2] *= 3;
     foo(args);
}

Ali