Super simple VM

1 files changed, 102 insertions, 0 deletions

diff --git a/src/vm.rs b/src/vm.rs
new file mode 100644
index 0000000..6b26b65
--- /dev/null
+++ b/src/vm.rs
@@ -0,0 +1,102 @@
+
+#[derive(Debug, Clone, Copy)]
+pub enum Value {
+    Float(f64),
+    Int(i64),
+    Bool(bool),
+}
+
+#[derive(Debug)]
+pub enum Op {
+    Pop,
+    Constant(Value),
+    Print,
+    Return,
+}
+
+#[derive(Debug)]
+pub struct Block {
+    name: String,
+    ops: Vec<Op>,
+}
+
+impl Block {
+    pub fn new(name: &str) -> Self {
+        Self {
+            name: String::from(name),
+            ops: Vec::new(),
+        }
+    }
+
+    pub fn add(&mut self, op: Op) -> usize {
+        self.ops.push(op);
+        self.ops.len()
+    }
+}
+
+#[derive(Debug)]
+pub struct VM {
+    stack: Vec<Value>,
+
+    block: Block,
+    ip: usize,
+}
+
+pub fn run_block(block: Block) {
+    let mut vm = VM {
+        stack: Vec::new(),
+
+        block,
+        ip: 0,
+    };
+
+    vm.run();
+}
+
+impl VM {
+    pub fn run(&mut self) {
+        const PRINT_WHILE_RUNNING: bool = true;
+        const PRINT_BLOCK: bool = true;
+
+        if PRINT_BLOCK {
+            println!(" === {} ===", self.block.name);
+            for s in self.block.ops.iter() {
+                println!("| {:?}", s);
+            }
+            println!("");
+        }
+
+        loop {
+
+            if PRINT_WHILE_RUNNING {
+                print!("    [");
+                for s in self.stack.iter() {
+                    print!("{:?} ", s);
+                }
+                println!("]");
+
+                println!("{:?}", self.block.ops[self.ip]);
+            }
+
+            match self.block.ops[self.ip] {
+                Op::Pop => {
+                    self.stack.pop();
+                }
+
+                Op::Constant(value) => {
+                    self.stack.push(value);
+                }
+
+                Op::Print => {
+                    println!("PRINT: {:?}", self.stack[0]);
+                }
+
+                Op::Return => {
+                    return;
+                }
+            }
+
+            self.ip += 1;
+        }
+    }
+}