Fixed bug in repl not allowing using variables previously bound in REPL in new binding expression

2 files changed, 22 insertions, 16 deletions

diff --git a/TUTORIAL.md b/TUTORIAL.md
index 74384b1..1ba6642 100644
--- a/TUTORIAL.md
+++ b/TUTORIAL.md
@@ -89,7 +89,7 @@ false : bool
 Values can be bound to variables using the let expression.
 ```console
 > (let x 1)
-Bind saved
+x saved
 > x
 1 : int
 ```
@@ -119,11 +119,11 @@ and a function for checking if a integer is between two
 others.
 ```console
 > (let ++ (fn a int int (+ a 1)))
-Bind saved
+++ saved
 > (++ 1)
 2 : int
 > (let between (fn (a b c) (int int int) bool (and (< b c) (> b a))))
-Bind saved
+between saved
 > (between 1 2 3)
 true : bool
 > (between 1 0 3)
diff --git a/src/main.rs b/src/main.rs
index b507cbd..8a09cfd 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,6 +1,7 @@
 
 use myslip::parse::parsetree::parse_to_ast;
-use myslip::sexp::{SExp::*, SLeaf::{Nil, Let}, util::scons};
+use myslip::sexp::{SExp, SExp::*, SLeaf::Nil, util::scons};
+use myslip::r#type::Type::NilType;
 use std::{io, io::Write};
 
 fn main() {
@@ -26,7 +27,7 @@ fn repl() -> Result<(), io::Error> {
     let stdin = io::stdin();
     let mut stdout = io::stdout();
 
-    let mut binds = vec![];
+    let mut binds: Vec<SExp> = vec![];
 
     loop {
 
@@ -36,7 +37,7 @@ fn repl() -> Result<(), io::Error> {
 	    break;
 	}
 
-        let mut expression = match parse_to_ast(&input) {
+        let orig_expression = match parse_to_ast(&input) {
             Ok(SCons(a, b)) if *b == Atom(Nil) => *a,
             Ok(t) => t,
 	    Err(e) => {
@@ -44,22 +45,27 @@ fn repl() -> Result<(), io::Error> {
 		continue;
 	    },
         };
-
-	match &expression {
-	    SCons(l, _) if **l == Atom(Let) => match scons(expression.clone(), Nil).type_check() {
-		Ok(_) => {
-		    binds.push(expression);
-		    println!("Bind saved");
+	if let Some((name, _value)) = orig_expression.clone().check_let() {
+	    let mut expr = scons(orig_expression.clone(), scons(Nil, Nil));
+	    for i in 1..=binds.len() {
+		expr = scons(binds[binds.len() - i].clone(), expr);
+	    }
+	    match expr.type_check() {
+		Ok(NilType) => {
+		    binds.push(orig_expression);
+		    println!("{name} saved");
 		    continue;
 		},
 		Err(e) => {
-		    println!("Type error: {e}");
+		    println!("Type error: {}", e);
 		    continue;
-		}
-	    },
-	    _ => (),
+		},
+		Ok(_) => (),
+	    }
 	}
 
+	let mut expression = orig_expression.clone();
+
 	for i in 1..=binds.len() {
 	    expression = scons(binds[binds.len() - i].clone(), expression);
 	}