Re: [boost] [gsoc16] Can I quickly check if the below really is the best approach?

Subject: Re: [boost] [gsoc16] Can I quickly check if the below really is the best approach?
From: Niall Douglas (s_sourceforge_at_[hidden])
Date: 2016-01-16 06:49:39

On 16 Jan 2016 at 15:06, Shangtong Zhang wrote:

> > // At global scope, allocates no memory whatsoever
> > static const constexpr static_map<int, const char *> map {
> >  { 5, "apple" },
> >  { 8, "pear" },
> >  { 0, "banana" },
> >  ...
> > };
> > // Works
> > map[5]="orange";
> > assert(map[5] && !strcmp(map[5], "orange");
> 
> I have difficulty understanding this, 
> As variable map is const and constexpr, how can map[5]=“orange” work?
> I don’t know how to implement this, where to store the “orange”.
> Could anyone help me?

Good catch. You are right that if it is const, it cannot be modified 
without a compiler error. If it is constexpr, it can only be modified 
in a constexpr evaluation context, and otherwise not.

I'll fix the project idea description before I announce the call for 
GSoC project ideas which will be probably Monday.

Niall

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