Model ast without comments and errors

src/ast.rs

@@ -0,0 +1,150 @@
+#[derive(Debug, Clone)]
+struct Ident(String);
+
+#[derive(Debug, Clone)]
+enum NumLit {
+    /// - `0b_0001_1011`
+    /// - `-0b10`
+    Bin(i64, String),
+
+    /// - `12_345`
+    /// - `-7`
+    Dec(i64, String),
+
+    /// - `0x_c0_f3`
+    /// - `-0xB`
+    Hex(i64, String),
+}
+
+#[derive(Debug, Clone)]
+enum TableLitElem {
+    /// `a`
+    Positional(Box<Expr>),
+
+    /// `foo: a`
+    Named(Ident, Box<Expr>),
+}
+
+/// `'{ a, foo: b }`
+#[derive(Debug, Clone)]
+struct TableLit {
+    elems: Vec<TableLitElem>,
+    trailing_comma: bool,
+}
+
+#[derive(Debug, Clone)]
+enum Lit {
+    /// `nil`
+    Nil,
+
+    /// - `true`
+    /// - `false`
+    Bool(bool),
+
+    /// See [`NumLit`].
+    Num(NumLit),
+
+    /// - `"foo"`
+    /// - `"Hello world!\n"`
+    /// - `""`
+    String(String),
+
+    /// See [`TableLit`].
+    Table(TableLit),
+}
+
+#[derive(Debug, Clone)]
+enum TableConstrElem {
+    /// `a`
+    Positional(Box<Expr>),
+
+    /// `foo: a`
+    Named(Ident, Box<Expr>),
+
+    /// `[a]: b`
+    Indexed(Box<Expr>, Box<Expr>),
+}
+
+/// `{ a, b, foo: c, [d]: e }`
+#[derive(Debug, Clone)]
+struct TableConstr {
+    elems: Vec<TableConstrElem>,
+    trailing_comma: bool,
+}
+
+#[derive(Debug, Clone, Copy)]
+enum BinOp {
+    /// `+`
+    Add,
+    /// `-`
+    Sub,
+    /// `*`
+    Mul,
+    /// `/`
+    Div,
+    /// `%`
+    Mod,
+    /// `==`
+    Eq,
+    /// `!=`
+    Neq,
+    /// `and`
+    And,
+    /// `or`
+    Or,
+}
+
+#[derive(Debug, Clone)]
+enum Expr {
+    Lit(Lit),
+
+    /// See [`TableConstr`].
+    TableConstr(TableConstr),
+
+    /// `foo`
+    Var(Ident),
+
+    /// `[a]`
+    VarExpr(Box<Expr>),
+
+    /// `foo = a`
+    VarAssign(Ident, Box<Expr>),
+
+    /// `[a] = b`
+    VarExprAssign(Box<Expr>, Box<Expr>),
+
+    /// `-a`
+    Neg(Box<Expr>),
+
+    /// `not a`
+    Not(Box<Expr>),
+
+    /// `a.foo`
+    Field(Box<Expr>, Ident),
+
+    /// `a[b]`
+    FieldExpr(Box<Expr>, Box<Expr>),
+
+    /// `a.foo = b`
+    FieldAssign(Box<Expr>, Ident, Box<Expr>),
+
+    /// `a[b] = c`
+    FieldExprAssign(Box<Expr>, Box<Expr>, Box<Expr>),
+
+    /// - `a + b`
+    /// - `a == b`
+    /// - `a and b`
+    BinOp(Box<Expr>, BinOp, Box<Expr>),
+}
+
+#[derive(Debug, Clone)]
+enum Program {
+    /// At the beginning of the file:
+    /// ```text
+    /// module
+    /// ...
+    /// ```
+    Module(TableLit),
+
+    Expr(Expr),
+}