www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.bugs - [Issue 5379] New: std.array.replace fails on char[]s

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=5379

           Summary: std.array.replace fails on char[]s
           Product: D
           Version: D2
          Platform: x86
        OS/Version: Mac OS X
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Phobos
        AssignedTo: nobody puremagic.com
        ReportedBy: oag optusnet.com.au


--- Comment #0 from Oliver Goodman <oag optusnet.com.au> 2010-12-27 00:42:34
PST ---
import std.stdio;
import std.array;

void main() {
    char[] s = "abcdef".dup;
    char[] t = "xxxx".dup;
    replace(s, 2, 4, t);
    writefln("s = %s", s);
}

/+
Gives me the following compile error:

mymble:d oag$ dmd replace.d 
replace.d(7): Error: template std.array.replace(T,Range) if
(is(ElementType!(Range) == T)) does not match any function template declaration
replace.d(7): Error: template std.array.replace(T,Range) if
(is(ElementType!(Range) == T)) cannot deduce template function from argument
types !()(char[],int,int,char[])

It appears to think that ElementType!(char[]) is dchar.
+/

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Dec 27 2010
parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=5379


Lars T. Kyllingstad <bugzilla kyllingen.net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |bugzilla kyllingen.net
         Resolution|                            |WONTFIX


--- Comment #1 from Lars T. Kyllingstad <bugzilla kyllingen.net> 2011-01-03
05:55:54 PST ---
The thing is, char[] is assumed to be UTF-8 encoded, which means that one array
element doesn't necessarily correspond to one symbol (or, more precisely, one
code point may be composed of several code units).  That's why (from a range
point of view) the element type of char[] is dchar, which is UTF-32 encoded, or
"decoded" in the sense that one element is one symbol.

Here's an example to prove the point:

  char[] foo = "ångstrøm";
  replace(foo, 0, 1, "a");

If this were allowed, foo would not contain "angstrøm" as one may expect, it
would contain garbage.  This is because the first character, "å", spans two
array elements.

You have two options:

1. If you want to use std.array.replace() like this with character arrays, you
should use dchar[].

2. Use std.string.replace(), which works with strings but always allocates.


I am closing this as WONTFIX.  There are several people who disagree with dchar
being the range element type of char[], however, so feel free to reopen as an
enhancement request if you wish.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Jan 03 2011