Function suggest_valid_function

datafusion/sql/src/expr/function.rs:46–70

Suggest a valid function based on an invalid input function name Returns `None` if no valid matches are found. This happens when there are no functions registered with the context.

(
    input_function_name: &str,
    is_window_func: bool,
    ctx: &dyn ContextProvider,
)

/// Returns `None` if no valid matches are found. This happens when there are no
/// functions registered with the context.
pub fn suggest_valid_function(
    input_function_name: &str,
    is_window_func: bool,
    ctx: &dyn ContextProvider,
) -> Option<String> {
    let valid_funcs = if is_window_func {
        // All aggregate functions and builtin window functions
        let mut funcs = Vec::new();

        funcs.extend(ctx.udaf_names());
        funcs.extend(ctx.udwf_names());

        funcs
    } else {
        // All scalar functions and aggregate functions
        let mut funcs = Vec::new();

        funcs.extend(ctx.udf_names());
        funcs.extend(ctx.higher_order_function_names());
        funcs.extend(ctx.udaf_names());

        funcs
    };
    find_closest_match(valid_funcs, input_function_name)
}

/// Find the closest matching string to the target string in the candidates list, using edit distance(case insensitive)
/// Input `candidates` must not be empty otherwise an error is returned.