Pure functions as initializers for immutable structures?

[Tomek Sowiński]

Dnia 18-10-2010 o 20:53:15 Steven Schveighoffer <schveiguy at yahoo.com>  
napisał(a):

> On Mon, 18 Oct 2010 14:31:26 -0400, Tomek Sowiński <just at ask.me> wrote:
>
>> Initializing immutable structures is a source of constant grief.  
>> Anything non-trivial requires instancing a mutable structure,  
>> initializing it, and then either casting to immutable (it's up to you  
>> to ensure no alias leaked) or, not to violate the type system,  
>> duplicate the whole.
>
> Aren't we supposed to get so-called immutable constructors?

Haven't heard, can you point to the discussion?
Anyway, if these immutable ctors are defined inside the type, then the  
library writer may not provide a ctor suitable for your case (very  
possible).
Plus, if the thing I wrote is correct, why not?

> If that's not what you mean, can you give an example of such grief?

Build an immutable dictionary that would hold the program's options.

> I admit I don't use immutable structs/objects in day-to-day coding.

Some time ago I tried, swore loud, took hours to isolate & file several  
bugs. But I'll try again, as soon as I get sufficient adrenaline lust. ;)

-- 
Tomek