Feature/sliding imports

Configurations.md

@@ -6,7 +6,7 @@ A possible content of `rustfmt.toml` or `.rustfmt.toml` might look like this:
 
 ```toml
 indent_style = "Block"
-reorder_imports = false
+reorder_imports = "Off"
 ```
 
 Each configuration option is either stable or unstable.
@@ -2016,14 +2016,14 @@ impl Iterator for Dummy {
 
 ## `reorder_imports`
 
-Reorder import and extern crate statements alphabetically in groups (a group is
+Reorder import and extern crate statements in groups (a group is
 separated by a newline).
 
-- **Default value**: `true`
-- **Possible values**: `true`, `false`
-- **Stable**: Yes
+- **Default value**: `"Alphabetically"`
+- **Possible values**: `"Alphabetically"`, `"Length"`, `"Off"`
+- **Stable**: No
 
-#### `true` (default):
+#### `"Alphabetically"` (default):
 
 ```rust
 use dolor;
@@ -2032,7 +2032,7 @@ use lorem;
 use sit;
 ```
 
-#### `false`:
+#### `"Off"`:
 
 ```rust
 use lorem;

src/config/config_type.rs

@@ -290,6 +290,10 @@ macro_rules! create_config {
                     }
                 )+
             }
+            /*#[allow(unreachable_pub)]
+            pub fn reorder_imports(&self) -> ReorderImports {
+                self.reorder_imports
+            }*/
 
             fn set_width_heuristics(&mut self, heuristics: WidthHeuristics) {
                 let max_width = self.max_width.2;

src/config/mod.rs

@@ -86,7 +86,8 @@ create_config! {
     merge_imports: bool, false, false, "(deprecated: use imports_granularity instead)";
 
     // Ordering
-    reorder_imports: bool, true, true, "Reorder import and extern crate statements alphabetically";
+    reorder_imports: ReorderImports, ReorderImports::Alphabetically, false,
+        "Reorder import and extern crate statements";
     reorder_modules: bool, true, true, "Reorder module statements alphabetically in group";
     reorder_impl_items: bool, false, false, "Reorder impl items";
 
@@ -547,7 +548,7 @@ imports_indent = "Block"
 imports_layout = "Mixed"
 imports_granularity = "Preserve"
 group_imports = "Preserve"
-reorder_imports = true
+reorder_imports = "Alphabetically"
 reorder_modules = true
 reorder_impl_items = false
 type_punctuation_density = "Wide"

src/config/options.rs

@@ -462,3 +462,13 @@ pub enum MatchArmLeadingPipe {
     /// Preserve any existing leading pipes
     Preserve,
 }
+
+/// Reorder imports
+#[config_type]
+pub enum ReorderImports {
+    Alphabetically,
+
+    Length,
+
+    Off,
+}