WIP: fix: Preserve dotted-key ordering

Fixes toml-rs#163

crates/toml_edit/src/key.rs

@@ -32,6 +32,7 @@ pub struct Key {
     pub(crate) repr: Option<Repr>,
     pub(crate) leaf_decor: Decor,
     pub(crate) dotted_decor: Decor,
+    pub(crate) position: Option<usize>,
 }
 
 impl Key {
@@ -42,6 +43,7 @@ impl Key {
             repr: None,
             leaf_decor: Default::default(),
             dotted_decor: Default::default(),
+            position: Default::default(),
         }
     }
 
@@ -76,6 +78,12 @@ impl Key {
         self
     }
 
+    /// While creating the `Key`, add a table position to it
+    pub fn with_position(mut self, position: Option<usize>) -> Self {
+        self.position = position;
+        self
+    }
+
     /// Access a mutable proxy for the `Key`.
     pub fn as_mut(&mut self) -> KeyMut<'_> {
         KeyMut { key: self }
@@ -158,6 +166,16 @@ impl Key {
         }
     }
 
+    /// Get the position relative to other keys in parent table
+    pub fn position(&self) -> Option<usize> {
+        return self.position;
+    }
+
+    /// Set the position relative to other keys in parent table
+    pub fn set_position(&mut self, position: Option<usize>) {
+        self.position = position;
+    }
+
     /// Auto formats the key.
     pub fn fmt(&mut self) {
         self.repr = None;
@@ -190,6 +208,7 @@ impl Clone for Key {
             repr: self.repr.clone(),
             leaf_decor: self.leaf_decor.clone(),
             dotted_decor: self.dotted_decor.clone(),
+            position: self.position.clone(),
         }
     }
 }

crates/toml_edit/src/parser/inline_table.rs

@@ -40,7 +40,8 @@ fn table_from_pairs(
     // Assuming almost all pairs will be directly in `root`
     root.items.reserve(v.len());
 
-    for (path, (key, value)) in v {
+    for (position, (path, (mut key, value))) in v.into_iter().enumerate() {
+        key.set_position(Some(position));
         let table = descend_path(&mut root, &path)?;
 
         // "Likewise, using dotted keys to redefine tables already defined in [table] form is not allowed"
@@ -162,6 +163,7 @@ mod test {
             r#"{a = 1e165}"#,
             r#"{ hello = "world", a = 1}"#,
             r#"{ hello.world = "a" }"#,
+            r#"{ hello.world = "a", goodbye = "b", hello.moon = "c" }"#,
         ];
         for input in inputs {
             dbg!(input);

crates/toml_edit/src/parser/mod.rs

@@ -216,6 +216,10 @@ that
 key = "value"
 "#,
             r#"hello.world = "a"
+"#,
+            r#"hello.world = "a"
+goodbye = "b"
+hello.moon = "c"
 "#,
             r#"foo = 1979-05-27 # Comment
 "#,

crates/toml_edit/src/parser/state.rs

@@ -7,6 +7,8 @@ pub(crate) struct ParseState {
     root: Table,
     trailing: Option<std::ops::Range<usize>>,
     current_table_position: usize,
+    // Current position within a table, to help order dotted keys
+    current_value_position: usize,
     current_table: Table,
     current_is_array: bool,
     current_table_path: Vec<Key>,
@@ -20,6 +22,7 @@ impl ParseState {
             root: Table::new(),
             trailing: None,
             current_table_position: 0,
+            current_value_position: 0,
             current_table: root,
             current_is_array: false,
             current_table_path: Vec::new(),
@@ -74,6 +77,9 @@ impl ParseState {
         if let (Some(existing), Some(value)) = (self.current_table.span(), value.span()) {
             self.current_table.span = Some((existing.start)..(value.end));
         }
+        key.set_position(Some(self.current_value_position));
+        self.current_value_position += 1;
+
         let table = &mut self.current_table;
         let table = Self::descend_path(table, &path, true)?;
 
@@ -161,6 +167,7 @@ impl ParseState {
         }
 
         self.current_table_position += 1;
+        self.current_value_position = 0;
         self.current_table.decor = decor;
         self.current_table.set_implicit(false);
         self.current_table.set_dotted(false);