G'MIC exercises

Been readying my guided filter and have come to an annoyance in terms of echoing.

gmic sp tiger guided .,1,1

Apply guided filter on image [0], with guide image [0],...

Notice guide image [0] but I can’t reproduce it with a command that uses pass.

foo_pass_:
  v - pass$1 0 v + e[] "Name : '"{b}"'\nIndex: "$1

gmic sp tiger foo_pass_ .

Name : 'tiger_c1'
Index: .

The best I can do is

1 {b}, which yields tiger_c1. I want tiger; or

2 $1, which yields . or whatever the user inputs. I want the interpreted index, which in this case is [0].

Suggestions?