From 640a53cad82ca07c2281ffabd8f9918afccba873 Mon Sep 17 00:00:00 2001
From: Ava Hahn <ava@sunnypup.io>
Date: Sat, 11 Mar 2023 22:04:46 -0800
Subject: [PATCH] better eval and test for eval,quote

---
 Readme.org         |  4 ----
 src/stl.rs         | 22 ++++++++++++++++++++++
 src/stl/decl.rs    | 22 ++++++++++++++++++----
 tests/test_vars.rs | 32 ++++++++++++++++++++++++++++++++
 4 files changed, 72 insertions(+), 8 deletions(-)

diff --git a/Readme.org b/Readme.org
index d1f8514..71d24ba 100644
--- a/Readme.org
+++ b/Readme.org
@@ -301,10 +301,6 @@ This contains any executable target of this project. Notably the main shell file
 Note: this section will not show the status of each item unless you are viewing it with a proper orgmode viewer.
 Note: this section only tracks the state of incomplete TODO items. Having everything on here would be cluttered.
 
-*** TODO Quote function
-    (just needs tests and stl entries)
-*** TODO Eval function
-    (just needs tests and stl entries)
 *** TODO list contains via circuit
 *** TODO Lambda hack
 BAD IDEAS
diff --git a/src/stl.rs b/src/stl.rs
index 39bd96e..d72de59 100644
--- a/src/stl.rs
+++ b/src/stl.rs
@@ -470,6 +470,28 @@ pub fn static_stdlib(syms: &mut SymTable) -> Result<(), String> {
         },
     );
 
+    syms.insert(
+        "quote".to_string(),
+        Symbol {
+            name: String::from("quote"),
+            args: Args::Lazy(1),
+            conditional_branches: true,
+            docs: decl::QUOTE_DOCSTRING.to_string(),
+            value: ValueType::Internal(Rc::new(decl::quote_callback)),
+        },
+    );
+
+    syms.insert(
+        "eval".to_string(),
+        Symbol {
+            name: String::from("eval"),
+            args: Args::Lazy(1),
+            conditional_branches: true,
+            docs: decl::EVAL_DOCSTRING.to_string(),
+            value: ValueType::Internal(Rc::new(decl::eval_callback)),
+        },
+    );
+
     Ok(())
 }
 
diff --git a/src/stl/decl.rs b/src/stl/decl.rs
index 37ec731..452860b 100644
--- a/src/stl/decl.rs
+++ b/src/stl/decl.rs
@@ -26,17 +26,31 @@ pub fn quote_callback(ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
     if ast.len() > 1 {
         Err("do not quote more than one thing at a time".to_string())
     } else {
-        Ok(Ctr::Seg(ast.clone()))
+        Ok(*ast.car.clone())
     }
 }
 
-pub const EVAL_DOCSTRING: &str = "takes an unevaluated argument and evaluates it.";
+pub const EVAL_DOCSTRING: &str = "takes an unevaluated argument and evaluates it.
+Specifically, does one pass of the tree simplification algorithm.
+If you have a variable referencing another variable you will get the
+referenced variable.";
 
 pub fn eval_callback(ast: &Seg, syms: &mut SymTable) -> Result<Ctr, String> {
     if ast.len() > 1 {
-        Err("do not quote more than one thing at a time".to_string())
+        Err("do not eval more than one thing at a time".to_string())
     } else {
-        Ok(*eval(ast, syms)?.clone())
+        match *ast.car {
+            Ctr::Seg(ref s) => Ok(*eval(s, syms)?.clone()),
+            Ctr::Symbol(ref sym) => {
+                let intermediate = syms.call_symbol(sym, &Seg::new(), true)?;
+                if let Ctr::Seg(ref s) = *intermediate {
+                    Ok(*eval(s, syms)?.clone())
+                } else {
+                    Ok(*intermediate)
+                }
+            },
+            _ => Ok(*ast.car.clone())
+        }
     }
 }
 
diff --git a/tests/test_vars.rs b/tests/test_vars.rs
index 818b108..47a8d76 100644
--- a/tests/test_vars.rs
+++ b/tests/test_vars.rs
@@ -265,4 +265,36 @@ mod var_lib_tests {
         eval(&env_tree, &mut syms).unwrap();
         eval(&tst_tree, &mut syms).unwrap();
     }
+
+    #[test]
+    fn test_quote() {
+        let document = "(quote (add 1 2))";
+        let result = "(add 1 2)";
+        let mut syms = SymTable::new();
+        static_stdlib(&mut syms).unwrap();
+        dynamic_stdlib(&mut syms).unwrap();
+        assert_eq!(
+            *eval(&lex(&document.to_string()).unwrap(), &mut syms)
+                .unwrap()
+                .to_string(),
+            result.to_string(),
+        );
+    }
+
+    #[test]
+    fn test_eval() {
+        let document = "
+          (let ((stored-tree (quote (add 1 2))))
+            (eval stored-tree)))";
+        let result = "3";
+        let mut syms = SymTable::new();
+        static_stdlib(&mut syms).unwrap();
+        dynamic_stdlib(&mut syms).unwrap();
+        assert_eq!(
+            *eval(&lex(&document.to_string()).unwrap(), &mut syms)
+                .unwrap()
+                .to_string(),
+            result.to_string(),
+        );
+    }
 }