use crate::{borrowed, file::File, owned, Span};use std::io; /// Represents a possible edit to the git configuration file#[must_use = "An edit must be added to an `Edits` instance to be effective"]enum Edit {    Delete(Span), // section or entry    SetSection(owned::Section),    SetEntry(owned::Entry),} impl Into<Edit> for owned::Section {    fn into(self) -> Edit {        Edit::SetSection(self)    }} impl Into<Edit> for owned::Entry {    fn into(self) -> Edit {        Edit::SetEntry(self)    }} /// Collects edits to be applied to a [`File`], to be written out eventually.pub struct Edits<'a> {    parent: &'a File,    edits: Vec<Edit>,} impl<'a> Edits<'a> {    pub fn delete_section(&mut self, section: &borrowed::Section<'_>) -> &mut Self {        self.edits.push(Edit::Delete(            self.parent.token(section.index).as_section().expect("section").name,        ));        self    }    pub fn delete_entry(&mut self, entry: &borrowed::Entry<'_>) -> &mut Self {        self.edits.push(Edit::Delete(            self.parent.token(entry.index).as_entry().expect("entry").name,        ));        self    }    // Use with [`owned::Section`].    //    // Newly [instantiated][owned::Section::new()] sections will be appended, and existing ones can be edited    // by calling [`borrowed::Section::to_editable()`].    pub fn create_or_update_section(&mut self, section: owned::Section) -> &mut Self {        self.edits.push(Edit::SetSection(section));        self    }    pub fn create_or_update_entry(&mut self, entry: owned::Entry) -> &mut Self {        self.edits.push(Edit::SetEntry(entry));        self    }     pub fn to_write(&self, _out: impl io::Write) -> io::Result<()> {        unimplemented!("to write")    }} impl File {    #[must_use = "Edits must be written using the `write_to(…)` method to be effective."]    pub fn edit(&self) -> Edits {        Edits {            parent: self,            edits: Vec::new(),        }    }}