Function build_use_function_edit

src/completion/use_edit.rs:403–442

Build an `additional_text_edits` entry that inserts a `use function` statement for the given fully-qualified function name at the alphabetically correct position in the file's existing use block. The sort key is prefixed with `"function "` so that function imports naturally group after class imports and among other function imports. When this is the first `use function` being added and there are

(
    fqn: &str,
    use_block: &UseBlockInfo,
)

/// Global functions never need importing.  Returns `None` when no import
/// is required.
pub(crate) fn build_use_function_edit(
    fqn: &str,
    use_block: &UseBlockInfo,
) -> Option<Vec<TextEdit>> {
    // Global functions (no namespace separator) never need importing.
    if !fqn.contains('\\') {
        return None;
    }

    // Use a prefixed sort key so function imports sort after class
    // imports and sit among other function imports.
    let sort_key = format!("function {}", fqn.to_lowercase());

    // Skip if this exact function is already imported.
    if use_block.existing.iter().any(|(_, k)| k == &sort_key) {
        return None;
    }
    let insert_pos = use_block.insert_position_for_key(&sort_key);

    // Prepend a blank line when:
    // - There are no existing imports at all and the file has a
    //   namespace (separate namespace from the use block), or
    // - This is the first function import and there are already class
    //   imports (group separator).
    let separator = if (use_block.existing.is_empty() && use_block.has_namespace)
        || (!use_block.has_function_imports() && use_block.has_class_imports())
    {
        "\n"
    } else {
        ""
    };

    Some(vec![TextEdit {
        range: Range {
            start: insert_pos,
            end: insert_pos,
        },
        new_text: format!("{}use function {};\n", separator, fqn),
    }])
}

#[cfg(test)]
#[path = "use_edit_tests.rs"]