S-expressions with Marpa::R2: Grammar for Numbers

I use this to process s-expressions with Marpa::R2:

my $DSL = <<'DSL';
:default ::= action => ::first
lexeme default = latm => 1

start ::= sexp

sexp ::= list
       | atom

list ::= LPAREN elements RPAREN action => Sexp::Tiny::Actions::do_list
elements ::= element* action => Sexp::Tiny::Actions::do_elements
element ::= sexp

atom ::= string
       | symbol

string ::= DQUOTE string_chars DQUOTE action => Sexp::Tiny::Actions::do_string
         | DQUOTE DQUOTE            action => Sexp::Tiny::Actions::do_empty_string

string_chars ::= string_char+ action => Sexp::Tiny::Actions::do_join
string_char  ::= STRCHAR

DQUOTE  ~ '"'
STRCHAR ~ [^"]


symbol ::= symbol_chars action => Sexp::Tiny::Actions::do_symbol
symbol_chars ::= symbol_char+ action => Sexp::Tiny::Actions::do_join
symbol_char  ::= SYMCHAR
SYMCHAR ~ [^()\s"]

LPAREN ~ '('
RPAREN ~ ')'

:discard ~ WS
WS ~ [\s]+

DSL

Probably awkward and there are certainly better ways, but it works: (i skip the processing part):

karl@pazuzu:~/src/perl/debug/sexp-tiny$ bin/sexp.pl examples/fossil.dat                                                                
{  fields => {
              "anonymous"           => "off",
              "canonical-url"       => "https://goethebier.space/fossil/p-acme",
              "crlf-glob"           => "*.bat *.cmd",
              "crnl-glob"           => "",
              "default-user"        => "karl",
              "hash-policy"         => "sha3",              "http-port"           => 8081,
              "ignore-glob"         => ["*.o", "*.swp", "*.tmp", ".direnv/", "_build/", "_opam/"],
              "localauth"           => "on",
              "max-upload"          => "20MB",              "project-description" => "Private ACME tooling repository",
              "project-name"        => "p-acme",
              "ssl-ca-location"     => "/etc/ssl/certs",
              "throttle"            => 0,
              "timeline-utc"        => "on",
            },
  type   => "fossil",
}

But it only works for strings so far:

karl@pazuzu:~/src/perl/debug/sexp-tiny$ echo '(acme (foo "bar"))' | bin/sexp.pl { fields => { foo => "bar" }, type => "acme" }

But not with numbers:

karl@pazuzu:~/src/perl/debug/sexp-tiny$ echo '(acme (x 1))' | bin/sexp.pl 
bin/sexp.pl expected (key value...)

I can only pass them in as string:

karl@pazuzu:~/src/perl/debug/sexp-tiny$ echo '(acme (x "1"))' | bin/sexp.pl 
{ fields => { x => 1 }, type => "acme" }

How must i modify the grammar to handle numbers (float and int)? I didn't find an example yet.