supports assignemtn

components/lox-compile/src/compile.rs

@@ -80,6 +80,10 @@ fn compile_expr(db: &dyn crate::Db, expr: &syntax::Expr, chunk: &mut Chunk) {
             let word_str = word.as_str(db);
             chunk.emit_byte(Code::Variable(word_str.to_string()))
         }
-        syntax::Expr::Assign { name, value } => todo!(),
+        syntax::Expr::Assign { name, value } => {
+            compile_expr(db, value, chunk);
+            let name_str = name.as_str(db);
+            chunk.emit_byte(Code::Assign(name_str.to_string()))
+        }
     }
 }

components/lox-execute/src/vm.rs

@@ -234,6 +234,10 @@ impl VM {
                     let value = self.globals.get(&name).expect("variable not found");
                     self.push(value.clone());
                 }
+                bytecode::Code::Assign(name) => {
+                    let value = self.pop();
+                    self.globals.insert(name, value);
+                }
             }
             if let Some(step_inspect) = &mut step_inspect {
                 step_inspect(instruction, self);

components/lox-ir/src/bytecode.rs

@@ -21,6 +21,7 @@ pub enum Code {
     VarDeclaration(String),
     Variable(String),
     Nil,
+    Assign(String),
 }
 
 #[derive(PartialEq, Eq, Debug, Clone, Default)]

lox_tests/assignment.lox

@@ -1,2 +1,3 @@
 var a = 1;
-a = 2;
+a = 2;
+print a;

lox_tests/assignment/bytecode

@@ -8,8 +8,17 @@ Chunk {
         VarDeclaration(
             "a",
         ),
+        Constant(
+            F64(
+                2.0,
+            ),
+        ),
+        Assign(
+            "a",
+        ),
         Variable(
             "a",
         ),
+        Print,
     ],
 }

lox_tests/assignment/execute

@@ -14,12 +14,31 @@ execute: VarDeclaration(
 )
 stack: []
 
+execute: Constant(
+    F64(
+        2.0,
+    ),
+)
+stack: [
+    Number(
+        2.0,
+    ),
+]
+
+execute: Assign(
+    "a",
+)
+stack: []
+
 execute: Variable(
     "a",
 )
 stack: [
     Number(
-        1.0,
+        2.0,
     ),
 ]
 
+execute: Print
+stack: []
+

lox_tests/assignment/syntax

@@ -10,3 +10,6 @@ Expr {
         value: NumberLiteral(2),
     },
 }
+Print {
+    expr: Variable(a),
+}

lox_tests/assignment/token

@@ -1,5 +1,5 @@
 TokenTree {
-    source text: "var a = 1;\na = 2;",
+    source text: "var a = 1;\na = 2;\nprint a;",
     tokens: [
         Alphabetic(var),
         Whitespace(' '),
@@ -16,5 +16,10 @@ TokenTree {
         Whitespace(' '),
         Number(2),
         Semicolon,
+        Whitespace('\n'),
+        Alphabetic(print),
+        Whitespace(' '),
+        Alphabetic(a),
+        Semicolon,
     ],
 }