supports executing var decl

components/lox-execute/src/vm.rs

@@ -1,3 +1,5 @@
+use std::collections::HashMap;
+
 use lox_ir::bytecode;
 
 #[derive(Debug, Clone)]
@@ -118,6 +120,9 @@ pub struct VM {
     ip: usize,
 
     pub stack: Vec<Value>,
+
+    // global variables
+    globals: HashMap<String, Value>,
 }
 
 impl VM {
@@ -126,6 +131,7 @@ impl VM {
             chunk,
             ip: 0,
             stack: Vec::new(),
+            globals: HashMap::new(),
         }
     }
 
@@ -217,8 +223,13 @@ impl VM {
                     // FIXME: This should be a call to a intrinsic function.
                     println!("{:?}", value);
                 },
-                bytecode::Code::VarDeclaration(_) => todo!(),
-                bytecode::Code::Nil => todo!(),
+                bytecode::Code::VarDeclaration(name) => {
+                    let value = self.pop();
+                    self.globals.insert(name, value);
+                },
+                bytecode::Code::Nil => {
+                    self.push(Value::Nil);
+                },
             }
             if let Some(step_inspect) = &mut step_inspect {
                 step_inspect(instruction, self);

lox_tests/var.lox

@@ -1 +1,2 @@
-var a = 1;
+var a = 1;
+var b;

lox_tests/var/bytecode

@@ -8,5 +8,9 @@ Chunk {
         VarDeclaration(
             "a",
         ),
+        Nil,
+        VarDeclaration(
+            "b",
+        ),
     ],
 }

lox_tests/var/execute

@@ -0,0 +1,26 @@
+execute: Constant(
+    F64(
+        1.0,
+    ),
+)
+stack: [
+    Number(
+        1.0,
+    ),
+]
+
+execute: VarDeclaration(
+    "a",
+)
+stack: []
+
+execute: Nil
+stack: [
+    Nil,
+]
+
+execute: VarDeclaration(
+    "b",
+)
+stack: []
+

lox_tests/var/syntax

@@ -4,3 +4,7 @@ Var {
         NumberLiteral(1),
     ),
 }
+Var {
+    name: "b",
+    initializer: None,
+}

lox_tests/var/token

@@ -1,5 +1,5 @@
 TokenTree {
-    source text: "var a = 1;",
+    source text: "var a = 1;\nvar b;",
     tokens: [
         Alphabetic(var),
         Whitespace(' '),
@@ -9,5 +9,10 @@ TokenTree {
         Whitespace(' '),
         Number(1),
         Semicolon,
+        Whitespace('\n'),
+        Alphabetic(var),
+        Whitespace(' '),
+        Alphabetic(b),
+        Semicolon,
     ],
 }