initial commit, correctly parses simple example

src/ast.rs

@@ -0,0 +1,132 @@
+#[derive(Debug, Clone, Copy)]
+pub struct Position(pub usize);
+
+#[derive(Debug)]
+pub struct Script<'a> {
+    pub items: Vec<TopLevelItem<'a>>,
+}
+
+#[derive(Debug)]
+pub enum TopLevelItem<'a> {
+    GlobalVar(GlobalVar<'a>),
+    Function(Function<'a>),
+}
+
+#[derive(Debug)]
+pub struct GlobalVar<'a> {
+    pub position: Position,
+    pub visibility: Visibility,
+    pub name: &'a str,
+    pub type_: Type,
+}
+
+#[derive(Debug)]
+pub struct Function<'a> {
+    pub position: Position,
+    pub visibility: Visibility,
+    pub name: &'a str,
+    pub params: Vec<(&'a str, Type)>,
+    pub type_: Option<Type>,
+    pub body: Block<'a>,
+}
+
+#[derive(Debug)]
+pub struct Block<'a> {
+    pub statements: Vec<Statement<'a>>,
+    pub final_expression: Option<Expression<'a>>,
+}
+
+#[derive(Debug)]
+pub enum Statement<'a> {
+    LocalVariable(LocalVariable<'a>),
+    Poke {
+        mem_location: MemoryLocation<'a>,
+        value: Expression<'a>,
+    },
+    Expression(Expression<'a>),
+}
+
+#[derive(Debug)]
+pub struct MemoryLocation<'a> {
+    pub position: Position,
+    pub size: MemSize,
+    pub left: Expression<'a>,
+    pub right: Expression<'a>,
+}
+
+#[derive(Debug)]
+pub struct LocalVariable<'a> {
+    pub position: Position,
+    pub name: &'a str,
+    pub type_: Option<Type>,
+    pub value: Option<Expression<'a>>,
+}
+
+#[derive(Debug)]
+pub enum Expression<'a> {
+    I32Const(i32),
+    Variable {
+        position: Position,
+        name: &'a str,
+    },
+    Loop {
+        position: Position,
+        label: &'a str,
+        block: Box<Block<'a>>,
+    },
+    BranchIf {
+        position: Position,
+        condition: Box<Expression<'a>>,
+        label: &'a str,
+    },
+    BinOp {
+        position: Position,
+        op: BinOp,
+        left: Box<Expression<'a>>,
+        right: Box<Expression<'a>>,
+    },
+    LocalTee {
+        position: Position,
+        name: &'a str,
+        value: Box<Expression<'a>>,
+    },
+}
+
+#[derive(Debug)]
+pub enum BinOp {
+    Add,
+    Sub,
+    Mul,
+    Div,
+    Rem,
+    And,
+    Or,
+    Xor,
+    Eq,
+    Ne,
+    Gt,
+    Ge,
+    Lt,
+    Le,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum MemSize {
+    Byte,
+    Word,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Visibility {
+    Local,
+    Export,
+    Import,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Type {
+    I32,
+    I64,
+    F32,
+    F64,
+}