implement order strategy "alphabetical"

malva/src/doc_gen/stmt.rs

@@ -302,9 +302,12 @@ fn format_statements<'s>(
                     ..
                 }))
             ) {
-                use crate::config::DeclarationOrder;
+                use crate::{config::DeclarationOrder, helpers::sort_decl};
                 match declaration_order {
-                    DeclarationOrder::Alphabetical => {}
+                    DeclarationOrder::Alphabetical => {
+                        sortable_decls
+                            .sort_by(|(a, _), (b, _)| sort_decl::compare_in_alphabetical(a, b));
+                    }
                     DeclarationOrder::Smacss => {}
                     DeclarationOrder::Concentric => {}
                 }

malva/src/helpers/mod.rs

@@ -0,0 +1 @@
+pub mod sort_decl;

malva/src/helpers/sort_decl.rs

@@ -0,0 +1,19 @@
+use std::cmp::Ordering;
+
+pub fn compare_in_alphabetical(a: &str, b: &str) -> Ordering {
+    strip_vendor_prefix(a).cmp(strip_vendor_prefix(b))
+}
+
+pub fn strip_vendor_prefix(s: &str) -> &str {
+    s.strip_prefix('-')
+        .and_then(|s| {
+            let trimmed = s.trim_start_matches(|c: char| c.is_ascii_alphanumeric());
+            if s == trimmed {
+                None
+            } else {
+                Some(trimmed)
+            }
+        })
+        .and_then(|s| s.strip_prefix('-'))
+        .unwrap_or(s)
+}

malva/src/lib.rs

@@ -4,6 +4,7 @@ pub mod config;
 mod ctx;
 mod doc_gen;
 mod error;
+mod helpers;
 mod line_bounds;
 mod state;