On Wednesday, 16 October 2013 at 19:55:41 UTC, Simen Kjaeraas
wrote:
On 2013-10-16, 18:54, Daniel Davidson wrote:
On Thursday, 13 June 2013 at 12:29:57 UTC, Simen Kjaeraas
wrote:
On Thu, 13 Jun 2013 14:17:22 +0200, Stephan Schiffels
<[email protected]> wrote:
For example, is there a way of instantiating an object
normally (i.e. mutable), and then later "freeze" it to
immutable via a simple cast or so?
In std.exception there is assumeUnique. It's basically just a
cast, but
might be good enough for you.
Is there any other recourse here?
Why does making `this(...) immutable` fix things below?
Shouldn't that immutable designation mean no members of this
will be modified? But that is the whole point of an
initializer? Why does immutable make sense in this context at
all?
Immutable in the case of constructors means that the instance
will be
created using only data implicitly castable to immutable. That
way, when
construction is finished, it is safe for the type system to
mark the
result as immutable.
My problem is a bit more elaborate and unfortunately to
initialize members I need to call standard functions that have
not been made pure (but should be).
If you're calling functions that are not marked pure in order
to create
immutable data, you will need to cast to immutable afterwards.
If you
know this is safe, no problem.
I'm in the learn news group for a reason. I think what you say
makes sense - a cast is required. But perhaps you have more
confidence that there is no problem. You and dicebot surely
disagree on this practice as he sees no real reason to ever
circumvent the type system.
It would benefit us all if you reported these functions or
created a pull
request for Phobos, of course.
I reported my issue with the `chain` function to this NG and
tried to start annotating items used by chain with pure to see
how far the thread led. Honestly it was quickly clear that it led
too far for me to follow it and someone else indicated the
problem had to do with Voldermort types. If there is more I could
do to "benefit us all", beyond learning how it works and what to
avoid in my own code - I will be glad to try.
