From 00ac922bd0f1216b9c2b37f92b9b1b980c66002d Mon Sep 17 00:00:00 2001
From: Roman Godmaire <godmaire@twilit.io>
Date: Sat, 4 May 2024 21:55:17 -0400
Subject: [PATCH] feat: basic quoting

...  I think this is right?
---
 src/env/core.rs  | 8 ++++++++
 src/evaluator.rs | 5 +++++
 2 files changed, 13 insertions(+)

diff --git a/src/env/core.rs b/src/env/core.rs
index 641521e..c82586e 100644
--- a/src/env/core.rs
+++ b/src/env/core.rs
@@ -35,6 +35,14 @@ pub(super) fn core() -> HashMap<String, Node> {
                 eval_node(env, Node::List(list))
             }),
         ),
+        (
+            "quote",
+            Node::Special(|_env, args| {
+                arg_count!(1, args.len());
+                let val = args.into_iter().next().unwrap();
+                Ok(val)
+            }),
+        ),
         // Arithmetic operations
         (
             "+",
diff --git a/src/evaluator.rs b/src/evaluator.rs
index f86a31a..859bf86 100644
--- a/src/evaluator.rs
+++ b/src/evaluator.rs
@@ -69,6 +69,7 @@ pub fn eval_node(env: &Environment, ast_node: Node) -> Result<Node> {
                 _ => Err(Error::InvalidOperator)?,
             }
         }
+
         Node::Symbol(sym) => env.get(&sym).ok_or(Error::NotInEnv(sym))?.to_owned(),
 
         val => val,
@@ -95,6 +96,10 @@ mod test {
     // Meta
     #[case("(eval (list + 1 1))", "2")]
     #[case("(apply + (list 1 2 3))", "6")]
+    #[case("'(1 2 3)", "(1 2 3)")]
+    #[case("(quote (1 2 3))", "(1 2 3)")]
+    #[case("'(1 2 (4 5) 6 7)", "(1 2 (4 5) 6 7)")]
+    #[case("(quote (1 2 (4 5) 6 7))", "(1 2 (4 5) 6 7)")]
     // Arithmetic
     #[case("(+ 1 2)", "3")]
     #[case("(- 5 1)", "4")]