• =?UTF-8?Q?Ali_=c3=87ehreli?= (18/18) Dec 15 2018 This one confused me until I decided to talk to a rubber ducky:
• bauss (8/28) Dec 16 2018 The reason it doesn't work in the second example is because it
• Steven Schveighoffer (6/27) Dec 16 2018 Hm... maybe a runtime error? I didn't think the compiler knows to
• =?UTF-8?Q?Ali_=c3=87ehreli?= (9/17) Dec 16 2018 Sorry, it was a runtime error. (I was seeing compile time because of the...

=?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:

This one confused me until I decided to talk to a rubber ducky:

import std.string;

void main() {
     auto s = "%s is a good number".format(42);
}

Fine; it works... Then the string becomes too long and I split it:

     auto s = "%s is a good number but one needs to know" ~
              " what the question exactly was.".format(42);

Now there is a compilation error:

   Orphan format arguments: args[0..1]

What? Is that a bug in format? It can't be because the string should be 
concatenated by the compiler as a single string, no? No: operator dot 
has precedence over ~, so format is applied to the second part of the 
string before the concatenation. Doh! This puzzled me a lot.

Anyway, the solution, once again, is to use parentheses:

     auto s = ("%s is a good number but one needs to know" ~
               " what the question exactly was.").format(42);

Ali

bauss <jj_1337 live.dk> writes:

On Sunday, 16 December 2018 at 00:34:48 UTC, Ali Çehreli wrote:
 This one confused me until I decided to talk to a rubber ducky:

 import std.string;

 void main() {
     auto s = "%s is a good number".format(42);
 }

 Fine; it works... Then the string becomes too long and I split 
 it:

     auto s = "%s is a good number but one needs to know" ~
              " what the question exactly was.".format(42);

 Now there is a compilation error:

   Orphan format arguments: args[0..1]

 What? Is that a bug in format? It can't be because the string 
 should be concatenated by the compiler as a single string, no? 
 No: operator dot has precedence over ~, so format is applied to 
 the second part of the string before the concatenation. Doh! 
 This puzzled me a lot.

 Anyway, the solution, once again, is to use parentheses:

     auto s = ("%s is a good number but one needs to know" ~
               " what the question exactly was.").format(42);

 Ali

The reason it doesn't work in the second example is because it 
translates to something like this:

auto s = "%s is a good number but one needs to know" ~ ("what the 
question exactly was.".format(42));

The reason encapsulation the two strings works is because you 
append the second string to the first before you call format.

Definitely not a bug.

Steven Schveighoffer <schveiguy gmail.com> writes:

On 12/15/18 7:34 PM, Ali Çehreli wrote:
 This one confused me until I decided to talk to a rubber ducky:
 
 import std.string;
 
 void main() {
      auto s = "%s is a good number".format(42);
 }
 
 Fine; it works... Then the string becomes too long and I split it:
 
      auto s = "%s is a good number but one needs to know" ~
               " what the question exactly was.".format(42);
 
 Now there is a compilation error:
 
    Orphan format arguments: args[0..1]

Hm... maybe a runtime error? I didn't think the compiler knows to 
complain about this.

 
 What? Is that a bug in format? It can't be because the string should be 
 concatenated by the compiler as a single string, no? No: operator dot 
 has precedence over ~, so format is applied to the second part of the 
 string before the concatenation. Doh! This puzzled me a lot.

Yes, in fact that is kind of a difference from previous 
"auto-concatenation" if you just put whitespace between the strings.

-Steve

=?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:

On 12/16/2018 12:00 PM, Steven Schveighoffer wrote:

 Now there is a compilation error:

    Orphan format arguments: args[0..1]

 Hm... maybe a runtime error? I didn't think the compiler knows to
 complain about this.

Sorry, it was a runtime error. (I was seeing compile time because of the 
following.)

 Yes, in fact that is kind of a difference from previous
 "auto-concatenation" if you just put whitespace between the strings.

Yes. The reason for my confusion was, since the former is deprecated, I 
assumed the following two would exactly be the same:

   "hello" "world"
   "hello" ~ "world"

Whether they are the same depends on code around them; hence my post. :)

 -Steve

Ali