Function function_call 

pub fn function_call(inner: &str) -> Option<FunctionCall<'_>>

Parse the call at the start of inner, or None if it does not start with name(. A name is [A-Za-z_][A-Za-z0-9_.]*, so a schema-qualified public.my_fn() parses too; whitespace may sit between it and (. The closing ) is the one that balances the opening (.