replace mutex with rwlock

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

src/eval.rs

@@ -36,11 +36,10 @@ pub fn eval (
     let mut cdr = Box::from(Ctr::None);
 
     // lets me redirect the input
+    let table_handle = SYM_TABLE.read().unwrap();
     let mut arg_car = &ast.car;
     let mut arg_cdr = &ast.cdr;
 
-    let table_handle = SYM_TABLE.lock().unwrap();
-
     // iterate over ast and build out ret
     let mut none = false;
     while !none {
@@ -68,7 +67,6 @@ pub fn eval (
                 }
             }
 
-            // im tired please simplify this
             Ctr::Symbol(_) => {
                 if simplify_function_branches && first {
                     if let Some(func) = prefetched_function {

src/stl.rs

@@ -45,7 +45,7 @@ pub static LIB_STORE_NO_ENV: Symbol = Symbol {
 
 // TODO : declare function if arg list is long enough
 fn _store_callback (ast: &Seg, env_cfg: bool) -> Ctr {
-    let mut table_handle = SYM_TABLE.lock().unwrap();
+    let mut table_handle = SYM_TABLE.write().unwrap();
     let is_var = ast.len() == 2;
     if let Ctr::Symbol(ref identifier) = *ast.car {
         match &*ast.cdr {

src/sym.rs

@@ -18,14 +18,14 @@
 use crate::eval::eval;
 use crate::segment::{Seg, Ctr, Type};
 use std::collections::HashMap;
-use std::sync::Mutex;
+use std::sync::RwLock;
 use lazy_static::lazy_static;
 
 pub type SymTable = HashMap<String, Symbol>;
 
 lazy_static! {
-    pub static ref SYM_TABLE: Mutex<SymTable> = {
-        Mutex::new(SymTable::new())
+    pub static ref SYM_TABLE: RwLock<SymTable> = {
+        RwLock::new(SymTable::new())
     };
 }
 
@@ -172,7 +172,7 @@ impl Symbol {
 
                 // Prep var table for function execution
                 for n in 0..f.arg_syms.len() {
-                    if let Some(old) = SYM_TABLE.lock().unwrap()
+                    if let Some(old) = SYM_TABLE.write().unwrap()
                         .insert(f.arg_syms[n].clone(), Symbol{
                             name: f.arg_syms[n].clone(),
                             value: ValueType::VarForm(Box::new(args[n].clone())),
@@ -206,9 +206,9 @@ impl Symbol {
 
                 // clear local vars and restore previous values
                 for n in 0..f.arg_syms.len() {
-                    SYM_TABLE.lock().unwrap().remove(&f.arg_syms[n]);
+                    SYM_TABLE.write().unwrap().remove(&f.arg_syms[n]);
                     if let Some(val) = holding_table.remove(&f.arg_syms[n]) {
-                        SYM_TABLE.lock().unwrap().insert(f.arg_syms[n].clone(), val);
+                        SYM_TABLE.write().unwrap().insert(f.arg_syms[n].clone(), val);
                     }
                 }