On Monday, 8 June 2020 at 06:37:18 UTC, tirithen wrote:
How can I initialize my two dimensional array?
When I try to run the code below I get the error:
Error: non-constant expression ["user":[cast(Capability)0],
"administrator":[cast(Capability)1]]
Code:
enum Capability {
self,
administer
}
alias Capabilities = immutable Capability[];
private Capabilities[string] roleCapabilities = [
"user" : [Capability.self], "administrator" :
[Capability.administer]
];
I have tried adding more const and immutable prefixes but it
still gives me the same error. The goal is that
roleCapabilities should be an immutable/const two dimensional
array.
What you declare here is not a two dim array it's an associative
array.
Associative array implementation have limitations. To initialize
one that doesn't have const expr as key you can use a static
module constructor:
---
enum Capability {
self,
administer
}
alias Capabilities = immutable Capability[];
private Capabilities[string] roleCapabilities;
static this()
{
roleCapabilities = [
"user" : [Capability.self], "administrator" :
[Capability.administer]
];
}
---
which is done at runtime, just before the D main() get executed.
Notes:
1. You can also use a function containing a switch statement
instead of an assoc array.
2. the other way would work because it would be a static array,
the enum member giving an integer index:
---
enum Capability {
self,
administer
}
alias Capabilities = immutable Capability[];
private string[Capability.max + 1] roleCapabilities = [
Capability.self : "user",
Capability.administer : "administrator",
];
---
but I suppose that is different.
