• dsmith (14/14) Nov 26 2012 How can I make something like the following work without "Error:
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (22/36) Nov 26 2012 One way is to dispatch the selection to a "traits" template:
• Jacob Carlborg (11/25) Nov 26 2012 Use static-if, but you shouldn't use .stringof. Check the actual type
• dsmith (4/32) Nov 27 2012 Oh, the "static if" ... for compile time evaluation; seems
• Jonathan M Davis (4/6) Nov 27 2012 But the types are known at compile time. If you're doing anything with t...
• dsmith (3/10) Nov 27 2012 Indeed, based on the parameter in the function call.

"dsmith" <ds nomail.com> writes:

How can I make something like the following work without "Error: 
cannot append type double to type string[]" ?


T[] some_function(T[] var) {
  T[] var2;
  double a = 12.34;
  string b = "hello";

  if(typeof(var).stringof == "double") {
    var2 ~= a;
  }
  if(typeof(var).stringof == "string") {
    var2 ~= b;
  }

...
}

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

On 11/26/2012 09:03 PM, dsmith wrote:
 How can I make something like the following work without "Error: cannot
 append type double to type string[]" ?


 T[] some_function(T[] var) {
 T[] var2;
 double a = 12.34;
 string b = "hello";

 if(typeof(var).stringof == "double") {
 var2 ~= a;
 }
 if(typeof(var).stringof == "string") {
 var2 ~= b;
 }

 ...
 }

One way is to dispatch the selection to a "traits" template:

template valueToAdd(T : double)
{
     T valueToAdd = 12.34;
}

template valueToAdd(T : string)
{
     T valueToAdd = "hello";
}


T[] some_function(T)(T[] var) {
     T[] var2;
     var2 ~= valueToAdd!T;
     return var2;
}

import std.stdio;

void main()
{
     writeln(some_function([ 1.25, 2.75 ]));
     writeln(some_function([ "abc", "xyz" ]));
}

Ali

Jacob Carlborg <doob me.com> writes:

On 2012-11-27 06:03, dsmith wrote:
 How can I make something like the following work without "Error: cannot
 append type double to type string[]" ?


 T[] some_function(T[] var) {
   T[] var2;
   double a = 12.34;
   string b = "hello";

   if(typeof(var).stringof == "double") {
     var2 ~= a;
   }
   if(typeof(var).stringof == "string") {
     var2 ~= b;
   }

 ...
 }

Use static-if, but you shouldn't use .stringof. Check the actual type 
and not the string of the type:

static if(is(typeof(var) == double)) {
     var2 ~= a;
}

static if(is(typeof(var) == string)) {
     var2 ~= b;
}

-- 
/Jacob Carlborg

"dsmith" <ds nomail.com> writes:

On Tuesday, 27 November 2012 at 07:28:34 UTC, Jacob Carlborg 
wrote:
 On 2012-11-27 06:03, dsmith wrote:
 How can I make something like the following work without 
 "Error: cannot
 append type double to type string[]" ?


 T[] some_function(T[] var) {
  T[] var2;
  double a = 12.34;
  string b = "hello";

  if(typeof(var).stringof == "double") {
    var2 ~= a;
  }
  if(typeof(var).stringof == "string") {
    var2 ~= b;
  }

 ...
 }

 Use static-if, but you shouldn't use .stringof. Check the 
 actual type and not the string of the type:

 static if(is(typeof(var) == double)) {
     var2 ~= a;
 }

 static if(is(typeof(var) == string)) {
     var2 ~= b;
 }

Oh, the "static if" ... for compile time evaluation; seems 
unintuitive (no?) since data is encountered at run time.

Jonathan M Davis <jmdavisProg gmx.com> writes:

On Tuesday, November 27, 2012 11:30:31 dsmith wrote:
 Oh, the "static if" ... for compile time evaluation; seems
 unintuitive (no?) since data is encountered at run time.

But the types are known at compile time. If you're doing anything with types, 
it has to be done at compile time.

- Jonathan M Davis

"dsmith" <ds nomail.com> writes:

On Tuesday, 27 November 2012 at 10:45:19 UTC, Jonathan M Davis 
wrote:
 On Tuesday, November 27, 2012 11:30:31 dsmith wrote:
 Oh, the "static if" ... for compile time evaluation; seems
 unintuitive (no?) since data is encountered at run time.

 But the types are known at compile time. If you're doing 
 anything with types,
 it has to be done at compile time.

 - Jonathan M Davis

Indeed, based on the parameter in the function call.