1 files changed, 67 insertions, 0 deletions
diff --git a/src/ast.zig b/src/ast.zig
new file mode 100644
index 0000000..2f8f209
--- /dev/null
+++ b/src/ast.zig
@@ -0,0 +1,67 @@
+const std = @import("std");
+const tok = @import("tokenize.zig");
+
+const SyntaxError = error{SyntaxError};
+const expectedToken = error{ExpectedToken};
+
+pub const BinOp = enum {
+    Add,
+    Sub,
+    Mul,
+    Div,
+};
+
+pub const Literal = union(enum) {
+    Int: i32,
+};
+
+pub const Ast = union(enum) {
+    Expr: struct {
+        kind: ExprKind,
+    },
+    Stmt: struct {
+        kind: StmtKind,
+    },
+};
+
+const StmtKind = union(enum) {
+    exit: Ast.Expr,
+};
+
+const ExprKind = union(enum) {
+    Literal: Literal,
+    BinaryOp: struct {
+        op: BinOp,
+        left: Ast.Expr,
+        right: Ast.Expr,
+    },
+};
+
+fn checkType(token: tok.Token, typ: tok.TokenType) bool {
+    return switch (token) {
+        typ => true,
+        else => false,
+    };
+}
+
+const AstParser = struct {
+    tokens: tok.Iterator(tok.Token),
+    fn parseStmt(self: *AstParser) !Ast.Stmt {
+        return switch (self.tokens.peek().?) {
+            .ret => try self.exitStmt(),
+        };
+    }
+
+    fn parseExpr(self: *AstParser) !Ast.Expr {
+
+    }
+
+    fn exitStmt(self: *AstParser) !Ast.Stmt {
+        if (!checkType(self.tokens.consume().?, tok.TokenType.ret)) return expectedToken;
+        const value = self.parseExpr();
+
+        if (!checkType(self.tokens.consume().?, tok.TokenType.semiCol)) return expectedToken;
+        const kind = StmtKind{ .exit = value };
+        return Ast.Stmt{ .kind = kind };
+    }
+};