starting to add an env so symbols can be found and functions run

src/types.rs

@@ -1,4 +1,5 @@
-use std::num::ParseIntError;
+use color_eyre::{eyre::eyre, Result};
+use std::{num::ParseIntError, rc::Rc};
 
 #[derive(Debug, Default, Clone, PartialEq, Eq, PartialOrd, Ord)]
 pub struct Expression {
@@ -15,6 +16,8 @@ impl From<&str> for Expression {
     }
 }
 
+pub type LispArgs = Vec<Value>;
+
 #[derive(Default, Debug, Clone, Eq, PartialEq, PartialOrd, Ord)]
 pub enum Value {
     List(Vec<Value>),
@@ -22,7 +25,7 @@ pub enum Value {
     Number(i64),
     #[default]
     Nil,
-    Function,
+    Function(fn(LispArgs) -> Result<Value>, Rc<Value>),
     True,
     Symbol(Symbol),
     Keyword(Keyword),
@@ -35,6 +38,17 @@ impl Value {
             _ => Self::Nil,
         }
     }
+
+    pub fn func(f: fn(LispArgs) -> Result<Value>) -> Self {
+        Self::Function(f, Rc::new(Self::Nil))
+    }
+
+    pub fn apply(&self, args: LispArgs) -> Result<Value> {
+        match self {
+            Self::Function(f, _) => f(args),
+            _ => Err(eyre!("No function here, shouldn't call apply")),
+        }
+    }
 }
 
 impl From<Vec<Value>> for Value {
@@ -54,10 +68,6 @@ impl From<&str> for Value {
             Value::True
         } else if s.starts_with(r#"""#) {
             Value::String(s.replace('"', ""))
-        } else if s == "fn".to_owned() {
-            Value::Function
-        } else if s == "defun".to_owned() {
-            Value::Function
         } else if s == "nil".to_owned() {
             Value::Nil
         } else {