• Peter Eisenhower (8/8) Oct 29 2013 I am confused as to why I cannot pass the return of the tag
• Peter Eisenhower (5/13) Oct 29 2013 This is the compile error
• Jonathan M Davis (6/16) Oct 29 2013 parse takes the string by ref and removes what it's parsing from the str...
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (19/27) Oct 30 2013 A trivial wrapper makes it convenient:
• Peter Eisenhower (2/32) Nov 03 2013 Thanks

"Peter Eisenhower" <peter.eisenhower gmail.com> writes:

I am confused as to why I cannot pass the return of the tag 
attribute directly into the parse int.

// This works
  string s = xml.tag.attr["key"];
  int key = parse!int(s);

// Compile error on these
int key = parse!int(xml.tag.attr["key"]);
int key = parse!int(cast(string) cml.tag.attr["key"]);

"Peter Eisenhower" <peter.eisenhower gmail.com> writes:

On Wednesday, 30 October 2013 at 01:02:45 UTC, Peter Eisenhower 
wrote:
 I am confused as to why I cannot pass the return of the tag 
 attribute directly into the parse int.

 // This works
  string s = xml.tag.attr["key"];
  int key = parse!int(s);

 // Compile error on these
 int key = parse!int(xml.tag.attr["key"]);
 int key = parse!int(cast(string) cml.tag.attr["key"]);

This is the compile error

Error: template instance 
std.conv.parse!(int,const(immutable(char)[])) error instantiating

"Jonathan M Davis" <jmdavisProg gmx.com> writes:

On Wednesday, October 30, 2013 02:02:40 Peter Eisenhower wrote:
 I am confused as to why I cannot pass the return of the tag
 attribute directly into the parse int.
 
 // This works
 string s = xml.tag.attr["key"];
 int key = parse!int(s);
 
 // Compile error on these
 int key = parse!int(xml.tag.attr["key"]);
 int key = parse!int(cast(string) cml.tag.attr["key"]);

parse takes the string by ref and removes what it's parsing from the string, 
so it can't be a temporary. It has to be an lvalue. Also, casting results in 
an rvalue. To use parse, you should generally be using a local variable for 
the string.

- Jonathan M Davis

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

On 10/29/2013 06:02 PM, Peter Eisenhower wrote:
 I am confused as to why I cannot pass the return of the tag attribute
 directly into the parse int.

 // This works
   string s = xml.tag.attr["key"];
   int key = parse!int(s);

 // Compile error on these
 int key = parse!int(xml.tag.attr["key"]);
 int key = parse!int(cast(string) cml.tag.attr["key"]);

A trivial wrapper makes it convenient:

import std.xml;
import std.conv;

T getAttr(T)(DocumentParser xml, string attrName)
{
     string s = xml.tag.attr[attrName];
     T attr = parse!T(s);
     return attr;
}

unittest
{
     auto xml = new DocumentParser(`<test key="1"></test>`);
     auto key = xml.getAttr!int("key");
     assert(key == 1);
}

void main()
{}

Ali

"Peter Eisenhower" <peter.eisenhower gmail.com> writes:

On Wednesday, 30 October 2013 at 18:19:13 UTC, Ali Çehreli wrote:
 On 10/29/2013 06:02 PM, Peter Eisenhower wrote:
 I am confused as to why I cannot pass the return of the tag 
 attribute
 directly into the parse int.

 // This works
  string s = xml.tag.attr["key"];
  int key = parse!int(s);

 // Compile error on these
 int key = parse!int(xml.tag.attr["key"]);
 int key = parse!int(cast(string) cml.tag.attr["key"]);

 A trivial wrapper makes it convenient:

 import std.xml;
 import std.conv;

 T getAttr(T)(DocumentParser xml, string attrName)
 {
     string s = xml.tag.attr[attrName];
     T attr = parse!T(s);
     return attr;
 }

 unittest
 {
     auto xml = new DocumentParser(`<test key="1"></test>`);
     auto key = xml.getAttr!int("key");
     assert(key == 1);
 }

 void main()
 {}

 Ali

Thanks