Function render_scalar_function_as 

pub fn render_scalar_function_as(
    form: ScalarFunctionForm,
    routine: &RoutineSpec,
) -> String

Spell this scalar function in a named grammar.

Parameters:

• form: the grammar to spell it in. Custom answers with the PostgreSQL form under a comment naming the grammar, so a dialect that is nearly one of these has something to start from;
• routine: the function, in the shape a Custom dialect receives it.