Function sql_impl_func

src/sql/src/func.rs:416–424

Constructs a definition for a built-in function out of a static SQL expression. The SQL expression should use the standard parameter syntax (`$1`, `$2`, ...) to refer to the inputs to the function. For example, a built-in function that takes two arguments and concatenates them with an arrow in between could be defined like so: sql_impl_func("$1 || '<->' || $2") The number of parameters in the S

(expr: &str)

// of parameters in the built-in's declaration. There is no support for variadic
// functions.
fn sql_impl_func(expr: &str) -> Operation<HirScalarExpr> {
    let invoke = sql_impl(expr);
    Operation::variadic(move |ecx, args| {
        let types = args.iter().map(|arg| ecx.scalar_type(arg)).collect();
        let mut out = invoke(ecx, types)?;
        out.splice_parameters(&args, 0);
        Ok(out)
    })
}

// Defines a built-in table function from a static SQL SELECT statement.
//