If you set $::RD_TRACE, it would tell you where it stopped working for the first time, by not matching the terminals or rule or subrules.

The following code works as per what you want.

$grammar = q(
       file: section(s) 
       section: header assign(s?)
       header: '[' /\w+/ ']'
       assign: pair comment(?)
       pair:   /\w+/ '=' /\w+/
       comment: /[\;\#]/ /\w+/
};
[download]

It gives you the output like:

header: [ Section1 ]
pair: key1 = value1
comment: # Comment
assign: 1 ARRAY(0x1d5e758)
pair: key2 = value2
comment: ; Comment
assign: 1 ARRAY(0x2014078)
pair: key3 = value3
assign: 1 ARRAY(0x1d5e818)
section: 1 ARRAY(0x1d5e74c)
header: [ Section2 ]
pair: key4 = value4
assign: 1 ARRAY(0x20140cc)
pair: key5 = value5
assign: 1 ARRAY(0x1d5e830)
section: 1 ARRAY(0x2014090)
file: ARRAY(0x2014084)
[download]

The removal of the '$' sign at the end of the 'assign' terms does the trick. I also seperated the comments from the key value pair.

artist