add bool var toggle function

Signed-off-by: Ava Hahn <ava@aidanis.online>

src/stl/boolean.rs

@@ -15,7 +15,7 @@
  */
 
 use crate::segment::{Ctr, Seg};
-use crate::sym::SymTable;
+use crate::sym::{SymTable, ValueType};
 
 pub fn bool_and_callback(ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
     let mut type_error = false;
@@ -71,6 +71,27 @@ pub fn bool_iseq_callback(_ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, Strin
     todo!()
 }
 
-pub fn bool_toggle_callback(_ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
-    todo!()
+pub fn bool_toggle_callback(ast: &Seg, syms: &mut SymTable) -> Result<Ctr, String> {
+    let var_name: String;
+    if let Ctr::Symbol(ref s) = *ast.car  {
+         var_name = s.clone();
+    } else {
+        return Err("argument to toggle should be a symbol".to_string())
+    }
+
+    let mut sym = syms.remove(&var_name).expect(&format!("symbol {var_name} is not defined"));
+    if let ValueType::VarForm(ref var) = sym.value {
+        if let Ctr::Bool(ref b) = **var {
+            sym.value = ValueType::VarForm(Box::new(Ctr::Bool(!b)));
+        } else {
+            syms.insert(var_name, sym);
+            return Err("can only toggle a boolean".to_string())
+        }
+    } else {
+        syms.insert(var_name, sym);
+        return Err("cannot toggle a function".to_string())
+    }
+
+    syms.insert(var_name, sym);
+    Ok(Ctr::None)
 }

src/stl/control.rs

@@ -116,9 +116,6 @@ pub fn let_callback(ast: &Seg, syms: &mut SymTable) -> Result<Ctr, String> {
                         return false
                     }
 
-                    let temp = var_val_res.clone().unwrap();
-                    println!("dbg: {}", temp);
-
                     localsyms.insert(name.clone(), Symbol {
                         name: name.clone(),
                         args: Args::None,