start bytecode compilation

src/bytecode.rs

@@ -0,0 +1,45 @@
+use crate::value::{HashMap, Symbol};
+use std::rc::Rc;
+
+#[derive(Debug, Default)]
+pub struct FnBlock {
+    pub code: Vec<Instr>,
+    pub stack_sizes: Vec<usize>,
+    pub arity: u8,
+}
+
+// todo: this should be copy in the end tbh
+#[derive(Debug)]
+pub enum Instr {
+    /// Store the current value on the stack to the stack location with the local offset `usize`
+    Store(usize),
+    /// Load the variable value from the local offset `usize` onto the stack
+    Load(usize),
+    /// Push a value onto the stack
+    PushVal(Box<Value>),
+    /// Negate the top value on the stack. Only works with numbers and booleans
+    Neg,
+    BinAdd,
+    BinSub,
+    BinMul,
+    BinDiv,
+    BinMod,
+    BinAnd,
+    BinOr,
+    CmpGreater,
+    CmpGreaterEq,
+    CmpLess,
+    CmpLessEq,
+    CmpEq,
+    CmpNotEq,
+}
+
+#[derive(Debug)]
+pub enum Value {
+    Null,
+    Bool(bool),
+    Num(f64),
+    String(Rc<str>),
+    Array(Vec<Value>),
+    Object(HashMap<Symbol, Value>),
+}