Function exported_shell 

pub fn exported_shell(
    name: &ShellName,
    sentence: &str,
    matched: Vec<GeneratedToken>,
    body: Vec<GeneratedToken>,
) -> Result<Vec<GeneratedToken>, Overflow>

The exported carrier: a hidden definition under the mangled name, with one rule matching what the delivery consumes and expanding to the body it guards.

Errors

Returns Overflow where the definition outgrows the declared token magnitude.