I'm trying to create an associative array where the keys will be a "string" type and the values will be function pointers. I'm using a custom type is called "file_struct" and for anyone that wants to try specifically with this type, the definition is the following:

struct file_struct {
  FILE* file;
  const char* name;
  size_t ln, cn, size;
  str identifier, type_buffer, type_buffer_tmp;

  void inc_ln() {
    this.cn = 0;
    this.ln++;
  }
}

The function pointers will point to a function that doesn't return anything and takes only one parameter that is of my custom "file_struct" type. More specifically, the signature is the following:

void function(ref file_struct)

So with that been said, I tried to create an associative array with the following code:

// Suppose that the function exists in another file
void parse_let(ref file_struct file) {}

immutable void function(ref file_struct)[string] common_identifiers = [
  "let"     : &parse_let,
  // "macro"   : &parse_macro,
];

When I try to compile it (I can only compile with "ldc2" because my code contains gcc-style inline assembly), I get the following error message:

main.d(12,71): Error: expression `["let":& parse_let]` is not a constant

Of course the file name and the number of line is relative to me case. Any ideas?

On Wednesday, 20 April 2022 at 10:42:59 UTC, rempas wrote:

You need shared static this for initializing immutable AA:

immutable void function(ref file_struct)[string] common_identifiers;

shared static this(){
	common_identifiers = [
      "let"     : &parse_let,
      // "macro"   : &parse_macro,
    ];
}

On Wednesday, 20 April 2022 at 11:10:18 UTC, vit wrote:

immutable void function(ref file_struct)[string] common_identifiers;

shared static this(){
	common_identifiers = [
      "let"     : &parse_let,
      // "macro"   : &parse_macro,
    ];
}

Unfortunately, this will not work for me as it uses "TypeInfo" and it is not available with "-betterC". Thank you for trying to help regardless!