NAME

IdClass - role for typed string IDs

SYNOPSIS

use IdClass;

class BlaId does IdClass {
    method prefix { "BLA" }
}

my BlaId $id = BlaId.new;
say $id;              # BLA-<ts>-<rest>

my Str $raw = $id.Str;
my BlaId $from-str = BlaId($raw);
say $from-str === $id; # True

sub load-item(BlaId() $item-id) {
    say "loading {$item-id}";
}

load-item $raw;   # coerces Str into BlaId

DESCRIPTION

IdClass provides a compact, typed identifier object with predictable string format and fast coercion from strings. The default string representation is:

PREFIX-TS-REST

Where PREFIX is a short, human-readable prefix, TS is a time-based segment, and REST is a random segment. The role is used directly in a class with custom methods like prefix, size, chars, and ts-scale.

ROLE

Use the role directly in a class and override the configuration methods when needed.

METHODS

prefix

method prefix

Returns the prefix string. Override this method in your class to supply the prefix.

size

method size

Returns the total size target used to compute the random segment length. The default is 40.

chars

method chars

Returns the character list used to generate the random segment.

ts-scale

method ts-scale

Returns the numeric scale applied to now when generating the timestamp segment. The default is 1000000.

Str

method Str

Returns the canonical string representation PREFIX-TS-REST.

gist

method gist

Same as Str.

COERCE

method COERCE(Str $id)

Coerces a string into the current class when the prefix matches. Coercion into IdClass itself is not implemented yet; only class-specific coercion is supported.

WHICH

method WHICH

Provides identity semantics based on the class name and string value.

FUNCTIONS

There are no helper factory functions. Define a class that does IdClass directly.

COERCION RULES

• A string must match PREFIX-TS-REST with three word-like segments. - If coercing into a specific IdClass-derived type, the prefix must match. - Coercion into IdClass itself is not implemented yet. - Invalid strings throw an exception.

EXAMPLES

use IdClass;

class UserId does IdClass {
    method prefix { "USR" }
}

class SessionId does IdClass {
    method prefix { "SES" }
}

class ShortId does IdClass {
    method prefix { "SHR" }
    method size   { 20 }
    method chars  { <A B C 1 2 3> }
}

class FastId does IdClass {
    method prefix            { "FST" }
    method ts-scale          { 1000 }
}

my UserId $user-id = UserId.new;
my Str $stored = $user-id.Str;      # save to storage

# Later: restore from storage
my UserId $restored = UserId($stored);

# Function parameters can coerce from Str
sub open-session(SessionId() $sid) {
    say "open {$sid}";
}

open-session SessionId.new.Str;

SEE ALSO

Raku Pod6/Rakudoc: https://docs.raku.org/language/pod