• Michael (10/12) Apr 27 2013 So, immutable string s = "..."; should be a manifest constant.
• Andrej Mitrovic (3/4) Apr 27 2013 Probably outdated documentation (and in upcoming 2.063 this will
• Minas Mina (2/14) Apr 27 2013 Because maybe string is already (immutable)char[]?
• Namespace (4/24) Apr 27 2013 immutable string is converted to immutable(string) which is
• Michael (6/8) Apr 28 2013 Immutable var itself is runtime constant (as mentioned here -
• Jonathan M Davis (15/33) Apr 27 2013 Because an immutable string _isn't_ a manifest constant. Only enums are

"Michael" <pr m1xa.com> writes:

According to http://dlang.org/const3.html

The simplest immutable declarations use it as a storage class.
It can be used to declare manifest constants.

So, immutable string s = "..."; should be a manifest constant.

If it is a constant that it can be used in switch(...).

switch(someStr)
{
    case s: ...; // Error: case must be a string or an integral 
constant, not s.
},

but string s = "..."; works good.

Why?

"Andrej Mitrovic" <andrej.mitrovich gmail.com> writes:

On Saturday, 27 April 2013 at 18:14:11 UTC, Michael wrote:
 Why?

Probably outdated documentation (and in upcoming 2.063 this will 
be enforced properly). Use enum instead.

"Minas Mina" <minas_mina1990 hotmail.co.uk> writes:

On Saturday, 27 April 2013 at 18:14:11 UTC, Michael wrote:
 According to http://dlang.org/const3.html

The simplest immutable declarations use it as a storage class.
It can be used to declare manifest constants.

 So, immutable string s = "..."; should be a manifest constant.

 If it is a constant that it can be used in switch(...).

 switch(someStr)
 {
    case s: ...; // Error: case must be a string or an integral 
 constant, not s.
 },

 but string s = "..."; works good.

 Why?

Because maybe string is already (immutable)char[]?

"Namespace" <rswhite4 googlemail.com> writes:

On Saturday, 27 April 2013 at 21:46:03 UTC, Minas Mina wrote:
 On Saturday, 27 April 2013 at 18:14:11 UTC, Michael wrote:
 According to http://dlang.org/const3.html

The simplest immutable declarations use it as a storage class.
It can be used to declare manifest constants.

 So, immutable string s = "..."; should be a manifest constant.

 If it is a constant that it can be used in switch(...).

 switch(someStr)
 {
   case s: ...; // Error: case must be a string or an integral 
 constant, not s.
 },

 but string s = "..."; works good.

 Why?

 Because maybe string is already (immutable)char[]?

immutable string is converted to immutable(string) which is 
converted to immutable(immutable(char)[]).
So no error with that.

"Michael" <pr m1xa.com> writes:

 Why?

 Because maybe string is already (immutable)char[]?

Immutable var itself is runtime constant (as mentioned here - 
docs are outdated), enum var is manifest constant (can be 
copypasted at compile time).
Now right way is 'enum string' ... or 'str.to!string()' that can 
be evaluated at compile time.


P.S.: Found this in previous similar topic.

Jonathan M Davis <jmdavisProg gmx.com> writes:

On Saturday, April 27, 2013 20:14:10 Michael wrote:
 According to http://dlang.org/const3.html
 
The simplest immutable declarations use it as a storage class.
It can be used to declare manifest constants.

 
 So, immutable string s = "..."; should be a manifest constant.
 
 If it is a constant that it can be used in switch(...).
 
 switch(someStr)
 {
     case s: ...; // Error: case must be a string or an integral
 constant, not s.
 },
 
 but string s = "..."; works good.
 
 Why?

Because an immutable string _isn't_ a manifest constant. Only enums are 
manifest constants.

immutable s = "foo";

or

immutable string s = "foo";

specifically create an immutable variable. It has an address and doesn't result 
in "foo" being copy-pasted everywhere that s is used like it would if s were 
an enum. It's no different from

string s = "foo";

or

auto s = "foo";

except that when is is immutable, it's implicitly shared, and you can't mutate 
it.

- Jonathna m Davis