feat: do statement for blocks

src/env/core.rs

@@ -2,7 +2,7 @@ use std::borrow::Borrow;
 use std::collections::HashMap;
 
 use crate::error::Error;
-use crate::evaluator::eval_node;
+use crate::evaluator::{eval, eval_node};
 use crate::macros::arg_count;
 use crate::node::Node;
 
@@ -347,6 +347,18 @@ pub(super) fn core() -> HashMap<String, Node> {
                 Ok(Node::String(val.to_string()))
             }),
         ),
+        (
+            "do",
+            Node::Special(|env, args| {
+                let res = eval(env, args)?;
+
+                if let Some(res) = res.last() {
+                    return Ok(res.to_owned());
+                }
+
+                Ok(Node::Nil)
+            }),
+        ),
         // IO
         (
             "display",