Improved for loop

parser/src/ast.rs

@@ -164,7 +164,8 @@ pub enum Statement {
         body: Box<Statement>,
     },
     For {
-        pattern: Identifier,
+        mutable: bool,
+        pattern: Pattern,
         iterator: Expression,
         body: Box<Statement>,
     },

parser/src/grammar.pest

@@ -142,7 +142,7 @@ c_for_stmt = {
 }
 
 for_stmt = {
-    "for" ~ "(" ~ identifier ~ "in" ~ expr ~ ")" ~ statement
+    "for" ~ "(" ~ mutable? ~ pattern ~ "in" ~ expr ~ ")" ~ statement
 }
 
 match_item = { pattern ~ "=>" ~ block }

parser/src/lib.rs

@@ -365,7 +365,8 @@ impl From<pest::iterators::Pair<'_, Rule>> for Statement {
             },
 
             Rule::for_stmt => Statement::For {
-                pattern: Identifier::from(inner.next().unwrap()),
+                mutable: listen_rule(&mut inner, Rule::mutable),
+                pattern: Pattern::from(inner.next().unwrap()),
                 iterator: inner.next().unwrap().into(),
                 body: Box::new(Statement::from(inner.next().unwrap())),
             },