On 04/07/2011 09:52 AM, spir wrote:
On 04/07/2011 03:07 AM, Ali Çehreli wrote:
Given an array of strings std.string.join() returns a single string:
import std.string;
void main() {
string[] a1 = ["hello", "red"];
string j1 = join(a1, " "); // OK
}
But in a program I need an array of mutable arrays of chars. If I join the
arrays I get a mutable array of chars.
[...]
Finally, casting ourselves works:
string j2 = cast(string)join(a2, " ");
Oh, that's very good news! Thans Ali, I never thought at that solution. I'm
often i/dup-ing from/to string to manipulate text due to the fact there is no
automatic conversion.
cast() works in place, doesn't it? so this is supposed avoid to avoid copy.
PS: Checked: indeed, it works in-place. But watch the gotcha:
unittest {
string s = "abc";
char[] chars = cast(char[])s;
chars ~= "de";
s = cast(string) chars;
writeln(s, ' ', chars); // abcde abcde
Sorry: forgot this line:
assert(s.ptr == chars.ptr); // pass
chars[1] = 'z';
writeln(s, ' ', chars); // azcde azcde
}
s's chars are mutable ;-) So, I guess there is /really/ no reason for implicite
casts between char[] and string no to exist. (I assumed the reason was
precisely to avoid such traps).
Denis
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