Macro tt_call::tt_is_comma

macro_rules! tt_is_comma {
    { $caller : tt input = [{ , }] } => { ... };
    { $caller : tt input = [{ $other : tt }] } => { ... };
}

Predicate that accepts a single token and determines whether it is a comma. ^[tt-call]

Input

• input = [{ a single token tree }]

Output

• is_comma = [{ either true or false }]