Hello Monks

We have a sudoers file that is a mess. I'm attempting to parse it out, and after a few attempts to basically roll my own parser, I found Marpa. I've read through the tutorial, and I thought I understood, so I build my grammar spec based on the Sudoers Manual... I was getting errors so I am attempting to break down my grammar into little pieces and build the grammar back up to the full spec.

I'm definitely missing something because I don't see anything wrong, but I'm getting an error...

Here's my small sample code:

#!/usr/bin/env perl
use strict;
use warnings;
use warnings;

use Marpa::R2;
my $grammar_spec    = get_grammar();
my $test_input      = test_input();

my $grammar = Marpa::R2::Scanless::G->new({ source => \$grammar_spec, 
+});
my $recce = Marpa::R2::Scanless::R->new({ grammar => $grammar });

$recce->read(\$test_input);

my $val = $recce->value;


sub get_grammar {
    return <<'END_GRAMMAR';
    :start              ::= Alias
    :discard            ~ ws

    Alias               ::= 'User_Alias'  User_Alias (':' User_Alias)*
    User_Alias          ::= NAME '=' User_List
    User_List           ::= User
                        | User ',' User_List

    User                ::= <user name>
    NAME                ~ [A-Z]([A-Z][0-9]_)*
    ws                  ~ [\s]+
    <user name>         ~ [a-z]([a-z][0-9]_)*

END_GRAMMAR
}

sub test_input {
    return <<'END_INPUT';
User_Alias FOO = abc, def
END_INPUT
}
[download]

The error I get is:

Error in SLIF parse: No lexemes accepted at line 4, column 70
* String before error:      ::= 'User_Alias'  User_Alias (':' User_Ali
+as)
* The error was at line 4, column 70, and at character 0x002a '*', ...
* here: *\n    User_Alias          ::= NAME '=' User_List\n
Marpa::R2 exception at test.pl line 10.
[download]

This seems to indicate the error is in the line:

    Alias               ::= 'User_Alias'  User_Alias (':' User_Alias)*
[download]

rewriting the Alias definition:

    Alias               ::= 'User_Alias'  User_Alias
[download]

Returns a new error:

Error in SLIF parse: No lexemes accepted at line 10, column 45
* String before error: ame>\n    NAME                ~ [A-Z]([A-Z][0-9
+]_)
* The error was at line 10, column 45, and at character 0x002a '*', ..
+.
* here: *\n    ws                  ~ [\\s]+\n    <user nam
Marpa::R2 exception at test.pl line 10.
[download]

So I'm thinking the problem lies in the second iteration of "User_Alias" i.e.: (':' User_Alias)* ... I'm just not sure what the problem is.

Also, the second error seems to indicate an issue with my NAME definition. column 40 is the dash between the 0 and 9 in "(A-Z0-9_)*"

I appreciate any thoughts or assistance.

Thanks!

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