Made tokens printable

src/config/verbosity.rs

@@ -6,7 +6,6 @@ use serde::Deserialize;
 #[derive(Default, Debug, Deserialize)]
 pub enum VerbosityLevel {
     /// No messages logged.
-    #[default]
     None,
 
     /// All messages are logged.
@@ -16,6 +15,7 @@ pub enum VerbosityLevel {
     Medium,
 
     /// Only high priority messages are logged.
+    #[default]
     High,
 }
 

src/interpreter/ast.rs

@@ -1,3 +1,5 @@
+use std::fmt;
+
 /// Token that is parsed by a [Parser] from source input and can be consumed by an [Interpreter].
 #[derive(Debug, Clone)]
 pub enum Token {
@@ -22,3 +24,25 @@ pub enum Token {
     /// Signals the [Interpreter] to read a byte from `stdin` and store it at the currently pointed at location.
     Read,
 }
+
+impl fmt::Display for Token {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::Inc => write!(f, "Inc"),
+            Self::Dec => write!(f, "Dec"),
+            Self::MoveRight => write!(f, "MoveRght"),
+            Self::MoveLeft => write!(f, "MoveLeft"),
+            Self::Loop(vec) => {
+                write!(f, "Loop[")?;
+
+                for ele in vec {
+                    write!(f, "{},", ele)?;
+                }
+
+                return write!(f, "]");
+            }
+            Self::Print => write!(f, "Print"),
+            Self::Read => write!(f, "Read"),
+        }
+    }
+}

src/interpreter/mod.rs

@@ -13,13 +13,17 @@ pub enum ProgramError {
 
     /// Error when performing an I/O operation.
     IOError,
+
+    /// Error when performing illegal operation
+    IllegalOperation 
 }
 
 impl fmt::Display for ProgramError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             ProgramError::OutOfBounds => write!(f, "Attempted to move pointer past end of buffer"),
             ProgramError::IOError => write!(f, "Error when attempting to perform IO operation"),
+            ProgramError::IllegalOperation => write!(f, "Operation is illegal")
         }
     }
 }
@@ -106,8 +110,16 @@ impl Interpreter {
     /// Processes the given [Token] and returns the result of its computation.
     fn process_token(&self, token: Token) -> Result<(), ProgramError> {
         match token {
-            Token::Inc => self.data.borrow_mut().inc(),
-            Token::Dec => self.data.borrow_mut().dec(),
+            Token::Inc => {
+                self.data.borrow_mut().inc();
+            }
+            Token::Dec => {
+                if self.data.borrow().get() == 0 {
+                    return Err(ProgramError::IllegalOperation);
+                }
+
+                self.data.borrow_mut().dec();
+            }
             Token::MoveLeft => {
                 if self.data.borrow().pointer() == 0 {
                     return Err(ProgramError::OutOfBounds);