concatenation

Simon Buerger krox at gmx.net
Mon Jan 24 16:54:30 PST 2011


On 25.01.2011 00:22, Robert Clipsham wrote:
> If you append something mutable to something immutable, the resulting
> type must be mutable, as some of the contents is mutable and could be
> changed - if that can happen the result can't be immutable. To get
> around this there's .idup I believe.
>

This is true in a more general sense, but not for 
string-concatenation. The ~ operator always creates a copy of the 
array elements. So even with
y = x ~ "";
y will point to different data than x, so it would be okay to be mutable.

Your statement is however true for arrays of 
Object/Pointer/any-reference-type instead of simple chars.

Krox


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