#! /usr/bin/env raku

use v6.d;

grammar Timestamp {
    rule TOP { <year><month><day>T<hours><minutes> }
    token year { \d**4 }
    token month { \d**2 }
    token day { \d**2 }
    token hours { \d**2 }
    token minutes { \d**2 }
}

grammar Filename {
# This line fails with:
# Cannot look up attributes in a Nil type object. Did you forget a '.new'?
#   in regex TOP at ./test-nesting-grammar.raku line 16
#   in block <unit> at ./test-nesting-grammar.raku line 23
    rule TOP { <name>'-'<timestamp>'.'<extension> }
    token name { <[a..z]>+ }
    token extension { <[a..z]>**3 }
}

Filename.^add_method("timestamp", -> *@_, *%_ { Timestamp.parse(@_[*-1].orig) });

Filename.parse('foo-20240102T1234.bar').say;