From 55a30afd06e6843dc5ca83c939f1f36fb24c8c37 Mon Sep 17 00:00:00 2001
From: Shautvast <shautvast@gmail.com>
Date: Sat, 1 Nov 2025 09:36:09 +0100
Subject: [PATCH] switched to thiserror for better error handling

---
 Cargo.lock               |   2 +-
 Cargo.toml               |   2 +-
 src/ast_compiler.rs      | 174 +++++++++++++++++++--------------------
 src/bytecode_compiler.rs |  15 ++--
 src/compiler_tests.rs    |  10 +--
 src/errors.rs            |  61 ++++++++++++++
 src/lib.rs               |  20 ++++-
 src/main.rs              |  21 +++--
 src/scanner.rs           |  21 ++---
 src/value.rs             |  72 ++++++++--------
 src/vm.rs                |  28 +++----
 11 files changed, 252 insertions(+), 174 deletions(-)
 create mode 100644 src/errors.rs

diff --git a/Cargo.lock b/Cargo.lock
index d7cc1f5..0f3f76e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -195,7 +195,6 @@ dependencies = [
 name = "crudlang"
 version = "0.1.0"
 dependencies = [
- "anyhow",
  "axum",
  "chrono",
  "dotenv",
@@ -203,6 +202,7 @@ dependencies = [
  "log4rs",
  "reqwest",
  "serde",
+ "thiserror",
  "tokio",
  "tokio-postgres",
  "tower",
diff --git a/Cargo.toml b/Cargo.toml
index e570c6a..7a6534a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,7 +17,7 @@ tower-http = { version = "0.6", features = ["fs"] }
 tower = "0.5.0"
 tracing = "0.1.41"
 tracing-subscriber = "0.3.20"
-anyhow = "1.0"
 tower-livereload = "0.9.6"
 log = "0.4.28"
 walkdir = "2.5.0"
+thiserror = "2.0.17"
diff --git a/src/ast_compiler.rs b/src/ast_compiler.rs
index 2c74aab..f1526ea 100644
--- a/src/ast_compiler.rs
+++ b/src/ast_compiler.rs
@@ -1,17 +1,17 @@
+use crate::errors::CompilerError::{self, Expected, IncompatibleTypes, ParseError, TooManyParameters, TypeError, UnexpectedIndent, UninitializedVariable};
 use crate::tokens::TokenType::{
-    Bang, Bool, Char, Colon, Date, Eof, Eol, Equal, F32, F64, False, FloatingPoint, Fn, Greater,
-    GreaterEqual, GreaterGreater, I32, I64, Identifier, Indent, Integer, LeftBrace, LeftBracket,
-    LeftParen, Less, LessEqual, LessLess, Let, ListType, MapType, Minus, Object, Plus, Print,
-    RightBrace, RightBracket, RightParen, SignedInteger, SingleRightArrow, Slash, Star, StringType,
-    True, U32, U64, UnsignedInteger,
+    Bang, Bool, Char, Colon, Date, Eof, Eol, Equal, False, FloatingPoint, Fn, Greater, GreaterEqual, GreaterGreater,
+    Identifier, Indent, Integer, LeftBrace, LeftBracket, LeftParen, Less, LessEqual, LessLess,
+    Let, ListType, MapType, Minus, Object, Plus, Print, RightBrace, RightBracket, RightParen, SignedInteger,
+    SingleRightArrow, Slash, Star, StringType, True, UnsignedInteger, F32, F64,
+    I32, I64, U32, U64,
 };
 use crate::tokens::{Token, TokenType};
 use crate::value::Value;
-use anyhow::anyhow;
 use log::debug;
 use std::collections::HashMap;
 
-pub fn compile(tokens: Vec<Token>) -> anyhow::Result<Vec<Statement>> {
+pub fn compile(tokens: Vec<Token>) -> Result<Vec<Statement>, CompilerError> {
     let mut compiler = AstCompiler::new(tokens);
     compiler.compile_tokens()
 }
@@ -49,13 +49,13 @@ impl AstCompiler {
         self.current = 0;
     }
 
-    fn compile_tokens(&mut self) -> anyhow::Result<Vec<Statement>> {
+    fn compile_tokens(&mut self) -> Result<Vec<Statement>,CompilerError> {
         self.collect_functions()?;
         self.reset();
         self.compile()
     }
 
-    fn compile(&mut self) -> anyhow::Result<Vec<Statement>> {
+    fn compile(&mut self) -> Result<Vec<Statement>, CompilerError> {
         if !self.had_error {
             let mut statements = vec![];
             while !self.is_at_end() {
@@ -68,23 +68,23 @@ impl AstCompiler {
             }
             Ok(statements)
         } else {
-            Err(anyhow::anyhow!("Compilation failed."))
+            Err(CompilerError::Failure)
         }
     }
 
-    fn collect_functions(&mut self) -> anyhow::Result<()> {
+    fn collect_functions(&mut self) -> Result<(), CompilerError> {
         while !self.is_at_end() {
             if self.match_token(vec![Fn]) {
-                let name_token = self.consume(Identifier, "Expect function name.")?;
-                self.consume(LeftParen, "Expect '(' after function name.")?;
+                let name_token = self.consume(Identifier, Expected("function name."))?;
+                self.consume(LeftParen, Expected("'(' after function name."))?;
                 let mut parameters = vec![];
                 while !self.check(RightParen) {
                     if parameters.len() >= 25 {
-                        return Err(anyhow::anyhow!("Too many parameters."));
+                        return Err(TooManyParameters);
                     }
-                    let parm_name = self.consume(Identifier, "Expect parameter name.")?;
+                    let parm_name = self.consume(Identifier, Expected("a parameter name."))?;
 
-                    self.consume(Colon, "Expect : after parameter name")?;
+                    self.consume(Colon, Expected(": after parameter name"))?;
                     let var_type = self.peek().token_type;
                     self.vars.push(Expression::Variable {
                         name: parm_name.lexeme.to_string(),
@@ -100,15 +100,15 @@ impl AstCompiler {
                         self.advance();
                     }
                 }
-                self.consume(RightParen, "Expect ')' after parameters.")?;
+                self.consume(RightParen, Expected(" ')' after parameters."))?;
                 let return_type = if self.check(SingleRightArrow) {
-                    self.consume(SingleRightArrow, "")?;
+                    self.consume(SingleRightArrow, Expected("->"))?;
                     self.advance().token_type
                 } else {
                     TokenType::Void
                 };
-                self.consume(Colon, "Expect colon (:) after function declaration.")?;
-                self.consume(Eol, "Expect end of line.")?;
+                self.consume(Colon, Expected("colon (:) after function declaration."))?;
+                self.consume(Eol, Expected("end of line."))?;
 
                 let function = Function {
                     name: name_token.clone(),
@@ -125,7 +125,7 @@ impl AstCompiler {
         Ok(())
     }
 
-    fn indent(&mut self) -> anyhow::Result<Option<Statement>> {
+    fn indent(&mut self) -> Result<Option<Statement>, CompilerError> {
         let expected_indent = *self.indent.last().unwrap();
         // skip empty lines
         while self.check(Eol) {
@@ -138,10 +138,9 @@ impl AstCompiler {
             indent_on_line += 1;
         }
         if indent_on_line > expected_indent {
-            panic!(
-                "unexpected indent level {} vs expected {}",
+            Err(UnexpectedIndent(
                 indent_on_line, expected_indent
-            );
+            ))
         } else if indent_on_line < expected_indent {
             self.indent.pop();
             return Ok(None);
@@ -150,7 +149,7 @@ impl AstCompiler {
         }
     }
 
-    fn declaration(&mut self) -> anyhow::Result<Statement> {
+    fn declaration(&mut self) -> Result<Statement, CompilerError> {
         if self.match_token(vec![Fn]) {
             self.function_declaration()
         } else if self.match_token(vec![Let]) {
@@ -162,10 +161,10 @@ impl AstCompiler {
         }
     }
 
-    fn object_declaration(&mut self) -> anyhow::Result<Statement> {
-        let type_name = self.consume(Identifier, "Expect object name.")?;
-        self.consume(Colon, "Expect ':' after object name.")?;
-        self.consume(Eol, "Expect end of line.")?;
+    fn object_declaration(&mut self) -> Result<Statement, CompilerError> {
+        let type_name = self.consume(Identifier, Expected("object name."))?;
+        self.consume(Colon, Expected("':' after object name."))?;
+        self.consume(Eol, Expected("end of line."))?;
 
         let mut fields = vec![];
 
@@ -181,13 +180,13 @@ impl AstCompiler {
                 }
             }
             if !done {
-                let field_name = self.consume(Identifier, "Expect an object field name.")?;
-                self.consume(Colon, "Expect ':' after field name.")?;
+                let field_name = self.consume(Identifier, Expected("an object field name."))?;
+                self.consume(Colon, Expected("':' after field name."))?;
                 let field_type = self.peek().token_type;
                 if field_type.is_type() {
                     self.advance();
                 } else {
-                    Err(anyhow::anyhow!("Expected a type"))?
+                    Err(Expected("a type"))?
                 }
                 fields.push(Parameter {
                     name: field_name,
@@ -195,26 +194,26 @@ impl AstCompiler {
                 });
             }
         }
-        self.consume(Eol, "Expect end of line.")?;
+        self.consume(Eol, Expected("end of line."))?;
         Ok(Statement::ObjectStmt {
             name: type_name,
             fields,
         })
     }
 
-    fn function_declaration(&mut self) -> anyhow::Result<Statement> {
-        let name_token = self.consume(Identifier, "Expect function name.")?;
-        self.consume(LeftParen, "Expect '(' after function name.")?;
+    fn function_declaration(&mut self) -> Result<Statement, CompilerError> {
+        let name_token = self.consume(Identifier, Expected("function name."))?;
+        self.consume(LeftParen, Expected("'(' after function name."))?;
         while !self.check(RightParen) {
             self.advance();
         }
 
-        self.consume(RightParen, "Expect ')' after parameters.")?;
+        self.consume(RightParen, Expected("')' after parameters."))?;
         while !self.check(Colon) {
             self.advance();
         }
-        self.consume(Colon, "2Expect colon (:) after function declaration.")?;
-        self.consume(Eol, "Expect end of line.")?;
+        self.consume(Colon, Expected("colon (:) after function declaration."))?;
+        self.consume(Eol, Expected("end of line."))?;
 
         let current_indent = self.indent.last().unwrap();
         self.indent.push(current_indent + 1);
@@ -228,8 +227,8 @@ impl AstCompiler {
         Ok(function_stmt)
     }
 
-    fn let_declaration(&mut self) -> anyhow::Result<Statement> {
-        let name_token = self.consume(Identifier, "Expect variable name.")?;
+    fn let_declaration(&mut self) -> Result<Statement, CompilerError> {
+        let name_token = self.consume(Identifier, Expected("variable name."))?;
 
         let declared_type = if self.check(Colon) {
             self.advance();
@@ -240,14 +239,14 @@ impl AstCompiler {
 
         if self.match_token(vec![Equal]) {
             let initializer = self.expression()?;
-            self.consume(Eol, "Expect end of line after initializer.")?;
+            self.consume(Eol, Expected("end of line after initializer."))?;
 
             let inferred_type = initializer.infer_type();
             let var_type = match calculate_type(declared_type, inferred_type) {
                 Ok(var_type) => var_type,
                 Err(e) => {
                     self.had_error = true;
-                    return Err(anyhow!("error at line {}: {}", name_token.line, e));
+                    return Err(TypeError(name_token.line, Box::new(e)));
                 }
             };
             self.vars.push(Expression::Variable {
@@ -261,11 +260,11 @@ impl AstCompiler {
                 initializer,
             })
         } else {
-            Err(anyhow::anyhow!("Uninitialized variables are not allowed."))?
+            Err(UninitializedVariable)?
         }
     }
 
-    fn statement(&mut self) -> anyhow::Result<Statement> {
+    fn statement(&mut self) -> Result<Statement, CompilerError> {
         if self.match_token(vec![Print]) {
             self.print_statement()
         } else {
@@ -273,68 +272,68 @@ impl AstCompiler {
         }
     }
 
-    fn print_statement(&mut self) -> anyhow::Result<Statement> {
+    fn print_statement(&mut self) -> Result<Statement, CompilerError> {
         let expr = self.expression()?;
-        self.consume(Eol, "Expect end of line after print statement.")?;
+        self.consume(Eol, Expected("end of line after print statement."))?;
         Ok(Statement::PrintStmt { value: expr })
     }
 
-    fn expr_statement(&mut self) -> anyhow::Result<Statement> {
+    fn expr_statement(&mut self) -> Result<Statement, CompilerError> {
         let expr = self.expression()?;
-        self.consume(Eol, "Expect end of line after expression.")?;
+        self.consume(Eol, Expected("end of line after expression."))?;
         Ok(Statement::ExpressionStmt { expression: expr })
     }
 
-    fn expression(&mut self) -> anyhow::Result<Expression> {
+    fn expression(&mut self) -> Result<Expression, CompilerError> {
         self.or()
     }
 
-    fn or(&mut self) -> anyhow::Result<Expression> {
+    fn or(&mut self) -> Result<Expression, CompilerError> {
         let expr = self.and()?;
         self.binary(vec![TokenType::LogicalOr], expr)
     }
 
-    fn and(&mut self) -> anyhow::Result<Expression> {
+    fn and(&mut self) -> Result<Expression, CompilerError> {
         let expr = self.bit_and()?;
         self.binary(vec![TokenType::LogicalAnd], expr)
     }
 
-    fn bit_and(&mut self) -> anyhow::Result<Expression> {
+    fn bit_and(&mut self) -> Result<Expression, CompilerError> {
         let expr = self.bit_or()?;
         self.binary(vec![TokenType::BitAnd], expr)
     }
 
-    fn bit_or(&mut self) -> anyhow::Result<Expression> {
+    fn bit_or(&mut self) -> Result<Expression, CompilerError> {
         let expr = self.bit_xor()?;
         self.binary(vec![TokenType::BitOr], expr)
     }
 
-    fn bit_xor(&mut self) -> anyhow::Result<Expression> {
+    fn bit_xor(&mut self) -> Result<Expression, CompilerError> {
         let expr = self.equality()?;
         self.binary(vec![TokenType::BitXor], expr)
     }
 
-    fn equality(&mut self) -> anyhow::Result<Expression> {
+    fn equality(&mut self) -> Result<Expression, CompilerError> {
         let expr = self.comparison()?;
         self.binary(vec![TokenType::EqualEqual, TokenType::BangEqual], expr)
     }
 
-    fn comparison(&mut self) -> anyhow::Result<Expression> {
+    fn comparison(&mut self) -> Result<Expression, CompilerError> {
         let expr = self.bitshift()?;
         self.binary(vec![Greater, GreaterEqual, Less, LessEqual], expr)
     }
 
-    fn bitshift(&mut self) -> anyhow::Result<Expression> {
+    fn bitshift(&mut self) -> Result<Expression, CompilerError> {
         let expr = self.term()?;
         self.binary(vec![GreaterGreater, LessLess], expr)
     }
 
-    fn term(&mut self) -> anyhow::Result<Expression> {
+    fn term(&mut self) -> Result<Expression, CompilerError> {
         let expr = self.factor()?;
         self.binary(vec![Minus, Plus], expr)
     }
 
-    fn factor(&mut self) -> anyhow::Result<Expression> {
+    fn factor(&mut self) -> Result<Expression, CompilerError> {
         let expr = self.unary()?;
         self.binary(vec![Slash, Star], expr)
     }
@@ -343,7 +342,7 @@ impl AstCompiler {
         &mut self,
         types: Vec<TokenType>,
         mut expr: Expression,
-    ) -> anyhow::Result<Expression> {
+    ) -> Result<Expression, CompilerError> {
         while self.match_token(types.clone()) {
             let operator = self.previous().clone();
             let right = self.comparison()?;
@@ -357,7 +356,7 @@ impl AstCompiler {
         Ok(expr)
     }
 
-    fn unary(&mut self) -> anyhow::Result<Expression> {
+    fn unary(&mut self) -> Result<Expression, CompilerError> {
         if self.match_token(vec![Bang, Minus]) {
             let operator = self.previous().clone();
             let right = self.unary()?;
@@ -371,7 +370,7 @@ impl AstCompiler {
         }
     }
 
-    fn primary(&mut self) -> anyhow::Result<Expression> {
+    fn primary(&mut self) -> Result<Expression, CompilerError> {
         debug!("primary {:?}", self.peek());
         Ok(if self.match_token(vec![LeftBracket]) {
             self.list()?
@@ -393,13 +392,13 @@ impl AstCompiler {
             Expression::Literal {
                 line: self.peek().line,
                 literaltype: Integer,
-                value: Value::I64(self.previous().lexeme.parse()?),
+                value: Value::I64(self.previous().lexeme.parse().map_err(|e|ParseError(format!("{:?}",e)))?),
             }
         } else if self.match_token(vec![FloatingPoint]) {
             Expression::Literal {
                 line: self.peek().line,
                 literaltype: FloatingPoint,
-                value: Value::F64(self.previous().lexeme.parse()?),
+                value: Value::F64(self.previous().lexeme.parse().map_err(|e|ParseError(format!("{:?}",e)))?),
             }
         } else if self.match_token(vec![StringType]) {
             Expression::Literal {
@@ -415,7 +414,7 @@ impl AstCompiler {
             }
         } else if self.match_token(vec![LeftParen]) {
             let expr = self.expression()?;
-            self.consume(RightParen, "Expect ')' after expression.")?;
+            self.consume(RightParen, Expected("')' after expression."))?;
             Expression::Grouping {
                 line: self.peek().line,
                 expression: Box::new(expr),
@@ -431,14 +430,14 @@ impl AstCompiler {
         })
     }
 
-    fn list(&mut self) -> anyhow::Result<Expression> {
+    fn list(&mut self) -> Result<Expression, CompilerError> {
         let mut list = vec![];
         while !self.match_token(vec![RightBracket]) {
             list.push(self.expression()?);
             if self.peek().token_type == TokenType::Comma {
                 self.advance();
             } else {
-                self.consume(RightBracket, "Expect ']' after list.")?;
+                self.consume(RightBracket, Expected("']' at the end of the list."))?;
                 break;
             }
         }
@@ -449,17 +448,17 @@ impl AstCompiler {
         })
     }
 
-    fn map(&mut self) -> anyhow::Result<Expression> {
+    fn map(&mut self) -> Result<Expression, CompilerError> {
         let mut entries = vec![];
         while !self.match_token(vec![RightBrace]) {
             let key = self.expression()?;
-            self.consume(Colon, "Expect ':' after map key.")?;
+            self.consume(Colon, Expected("':' after map key."))?;
             let value = self.expression()?;
             entries.push((key, value));
             if self.peek().token_type == TokenType::Comma {
                 self.advance();
             } else {
-                self.consume(RightBrace, "Expect '}' after map.")?;
+                self.consume(RightBrace, Expected("'}' after map."))?;
                 break;
             }
         }
@@ -470,7 +469,7 @@ impl AstCompiler {
         })
     }
 
-    fn variable_lookup(&mut self, token: &Token) -> anyhow::Result<Expression> {
+    fn variable_lookup(&mut self, token: &Token) -> Result<Expression, CompilerError> {
         let (var_name, var_type) = self
             .vars
             .iter()
@@ -482,7 +481,7 @@ impl AstCompiler {
                 }
             })
             .find(|e| e.0 == &token.lexeme)
-            .ok_or_else(|| return anyhow::anyhow!("Unknown variable: {:?}", token))?;
+            .ok_or_else(|| return CompilerError::UndeclaredVariable(token.clone()))?;
         Ok(Expression::Variable {
             name: var_name.to_string(),
             var_type: var_type.clone(),
@@ -490,20 +489,19 @@ impl AstCompiler {
         })
     }
 
-    fn function_call(&mut self, name: String) -> anyhow::Result<Expression> {
+    fn function_call(&mut self, name: String) -> Result<Expression, CompilerError> {
         let function_name = self.functions.get(&name).unwrap().name.lexeme.clone();
         let function = self.functions.get(&function_name).unwrap().clone();
 
         let mut arguments = vec![];
         while !self.match_token(vec![RightParen]) {
             if arguments.len() >= 25 {
-                return Err(anyhow::anyhow!("Too many parameters."));
+                return Err(TooManyParameters);
             }
             let arg = self.expression()?;
             let arg_type = arg.infer_type();
             if arg_type != function.parameters[arguments.len()].var_type {
-                return Err(anyhow::anyhow!(
-                    "Incompatible argument types. Expected {}, found {}",
+                return Err(IncompatibleTypes(
                     function.parameters[arguments.len()].var_type,
                     arg_type
                 ));
@@ -512,7 +510,7 @@ impl AstCompiler {
             if self.peek().token_type == TokenType::Comma {
                 self.advance();
             } else {
-                self.consume(RightParen, "Expect ')' after arguments.")?;
+                self.consume(RightParen, Expected("')' after arguments."))?;
                 break;
             }
         }
@@ -525,16 +523,17 @@ impl AstCompiler {
         })
     }
 
-    fn consume(&mut self, token_type: TokenType, message: &str) -> anyhow::Result<Token> {
+    fn consume(&mut self, token_type: TokenType, message: CompilerError) -> Result<Token, CompilerError> {
         if self.check(token_type) {
             self.advance();
         } else {
             self.had_error = true;
-            return Err(anyhow::anyhow!(
-                "{} at {:?}",
-                message.to_string(),
-                self.peek()
-            ));
+            // return Err(anyhow::anyhow!(
+            //     "{} at {:?}",
+            //     message.to_string(),
+            //     self.peek()
+            // ));
+            return Err(message);
         }
         Ok(self.previous().clone())
     }
@@ -580,7 +579,7 @@ impl AstCompiler {
 fn calculate_type(
     declared_type: Option<TokenType>,
     inferred_type: TokenType,
-) -> anyhow::Result<TokenType> {
+) -> Result<TokenType, CompilerError> {
     Ok(if let Some(declared_type) = declared_type {
         if declared_type != inferred_type {
             match (declared_type, inferred_type) {
@@ -596,8 +595,7 @@ fn calculate_type(
                 (U64, I32) => U64,
                 (StringType, _) => StringType, // meh, this all needs rigorous testing. Update: this is in progress
                 _ => {
-                    return Err(anyhow::anyhow!(
-                        "Incompatible types. Expected {}, found {}",
+                    return Err(IncompatibleTypes(
                         declared_type,
                         inferred_type
                     ));
@@ -615,7 +613,7 @@ fn calculate_type(
             ListType => ListType,
             MapType => MapType,
             Object => Object,
-            _ => panic!("Unexpected type"),
+            _ => return Err(CompilerError::UnexpectedType(inferred_type)),
         }
     })
 }
diff --git a/src/bytecode_compiler.rs b/src/bytecode_compiler.rs
index bd1db56..8e708ef 100644
--- a/src/bytecode_compiler.rs
+++ b/src/bytecode_compiler.rs
@@ -10,12 +10,13 @@ use crate::vm::{
     OP_RETURN, OP_SHL, OP_SHR, OP_SUBTRACT,
 };
 use std::collections::HashMap;
+use crate::errors::CompilerError;
 
 pub fn compile(
     namespace: Option<&str>,
     ast: &Vec<Statement>,
     registry: &mut HashMap<String, Chunk>,
-) -> anyhow::Result<()> {
+) -> Result<(),CompilerError> {
     compile_name(ast, namespace, registry)
 }
 
@@ -23,7 +24,7 @@ pub(crate) fn compile_function(
     function: &Function,
     registry: &mut HashMap<String, Chunk>,
     namespace: &str,
-) -> anyhow::Result<Chunk> {
+) -> Result<Chunk, CompilerError> {
     let mut compiler = Compiler::new(&function.name.lexeme);
     for parm in &function.parameters {
         let name = parm.name.lexeme.clone();
@@ -39,7 +40,7 @@ pub(crate) fn compile_name(
     ast: &Vec<Statement>,
     namespace: Option<&str>,
     registry: &mut HashMap<String, Chunk>,
-) -> anyhow::Result<()> {
+) -> Result<(),CompilerError> {
     let name=namespace.unwrap_or("main");
     let compiler = Compiler::new(name);
     let chunk = compiler.compile(ast, registry, name)?;
@@ -74,7 +75,7 @@ impl Compiler {
         ast: &Vec<Statement>,
         registry: &mut HashMap<String, Chunk>,
         namespace: &str,
-    ) -> anyhow::Result<Chunk> {
+    ) -> Result<Chunk, CompilerError> {
         //TODO can likely be removed
         for statement in ast {
             if let Statement::FunctionStmt { function } = statement {
@@ -99,7 +100,7 @@ impl Compiler {
         statement: &Statement,
         registry: &mut HashMap<String, Chunk>,
         namespace: &str,
-    ) -> anyhow::Result<()> {
+    ) -> Result<(), CompilerError> {
         self.current_line = statement.line();
         match statement {
             Statement::VarStmt {
@@ -140,7 +141,7 @@ impl Compiler {
         namespace: &str,
         expression: &Expression,
         registry: &mut HashMap<String, Chunk>,
-    ) -> anyhow::Result<()> {
+    ) -> Result<(), CompilerError> {
         match expression {
             Expression::FunctionCall {
                 name, arguments, ..
@@ -229,7 +230,7 @@ impl Compiler {
         var_type: &TokenType,
         name_index: usize,
         initializer: &Expression,
-    ) -> anyhow::Result<()> {
+    ) -> Result<(), CompilerError> {
         let def_op = match var_type {
             TokenType::I32 => OP_DEF_I32,
             TokenType::I64 => OP_DEF_I64,
diff --git a/src/compiler_tests.rs b/src/compiler_tests.rs
index 14a0a34..26ef21c 100644
--- a/src/compiler_tests.rs
+++ b/src/compiler_tests.rs
@@ -1,13 +1,13 @@
 #[cfg(test)]
 mod tests {
-    use crate::compile;
+    use crate::{compile, run};
     use crate::scanner::scan;
     use crate::value::Value;
     use crate::vm::interpret;
 
     #[test]
     fn literal_int() {
-        assert!(compile("1").is_ok());
+        assert_eq!(run("1"), Ok(Value::I64(1)));
     }
 
     #[test]
@@ -52,7 +52,7 @@ mod tests {
         if let Err(e) = &r {
             assert_eq!(
                 e.to_string(),
-                "error at line 1: Incompatible types. Expected u32, found i32/64"
+                "Type mismatch at line 1: Incompatible types. Expected u32, found i32/64"
             );
         }
     }
@@ -64,7 +64,7 @@ mod tests {
         if let Err(e) = &r {
             assert_eq!(
                 e.to_string(),
-                "error at line 1: Incompatible types. Expected u64, found i32/64"
+                "Type mismatch at line 1: Incompatible types. Expected u64, found i32/64"
             );
         }
     }
@@ -76,7 +76,7 @@ mod tests {
         if let Err(e) = &r {
             assert_eq!(
                 e.to_string(),
-                "error at line 1: Incompatible types. Expected u64, found string"
+                "Type mismatch at line 1: Incompatible types. Expected u64, found string"
             );
         }
     }
diff --git a/src/errors.rs b/src/errors.rs
new file mode 100644
index 0000000..c4d6772
--- /dev/null
+++ b/src/errors.rs
@@ -0,0 +1,61 @@
+use thiserror::Error;
+use crate::tokens::{Token, TokenType};
+
+#[derive(Error, Debug, PartialEq)]
+pub enum Error {
+    #[error(transparent)]
+    Compiler(#[from] CompilerError),
+    #[error(transparent)]
+    Runtime(#[from] RuntimeError),
+    #[error("Platform error {0}")]
+    Platform(String),
+}
+
+
+#[derive(Error, Debug, PartialEq)]
+pub enum CompilerError {
+    #[error("Compilation failed")]
+    Failure,
+    #[error("Too many parameters")]
+    TooManyParameters,
+    #[error("Expected {0}")]
+    Expected(&'static str),
+    #[error("unexpected indent level {0} vs expected {1}")]
+    UnexpectedIndent(usize,usize),
+    #[error("Type mismatch at line {0}: {1}")]
+    TypeError(usize, Box<CompilerError>),
+    #[error("Uninitialized variables are not allowed.")]
+    UninitializedVariable,
+    #[error("Incompatible types. Expected {0}, found {1}")]
+    IncompatibleTypes(TokenType, TokenType),
+    #[error("Error parsing number {0}")]
+    ParseError(String),
+    #[error("Undeclared variable: {0:?}")]
+    UndeclaredVariable(Token),
+    #[error("Unexpected identifier at line {0}")]
+    UnexpectedIdentifier(usize),
+    #[error("Unterminated {0} at line {1}")]
+    Unterminated(&'static str, usize),
+    #[error("Illegal char length for {0} at line {1}")]
+    IllegalCharLength(String, usize),
+    #[error("Unexpected type {0}")]
+    UnexpectedType(TokenType)
+}
+
+#[derive(Error, Debug, PartialEq)]
+pub enum RuntimeError {
+    #[error("Error while executing")]
+    Value(#[from] ValueError),
+    #[error("Error occurred")]
+    Something,
+    #[error("Expected {0}, got {1}")]
+    Expected(&'static str, &'static str),
+}
+
+#[derive(Error, Debug, PartialEq)]
+pub enum ValueError {
+    #[error("{0}")]
+    CannotAnd(&'static str),
+    #[error("{0}")]
+    Some(&'static str),
+}
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
index 541e929..00446c7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,20 +1,32 @@
-use std::collections::HashMap;
 use crate::scanner::scan;
+use crate::value::Value;
+use crate::vm::interpret;
+use std::collections::HashMap;
+use crate::errors::Error;
 
 pub mod ast_compiler;
 pub mod bytecode_compiler;
 pub mod chunk;
+mod compiler_tests;
 mod keywords;
 pub mod scanner;
-mod compiler_tests;
 mod tokens;
 mod value;
 pub mod vm;
+pub mod errors;
 
-pub fn compile(src: &str) -> anyhow::Result<HashMap<String, chunk::Chunk>> {
+pub fn compile(src: &str) -> Result<HashMap<String, chunk::Chunk>, Error> {
     let tokens = scan(src)?;
     let mut registry = HashMap::new();
-    let ast= ast_compiler::compile(tokens)?;
+    let ast = ast_compiler::compile(tokens)?;
     bytecode_compiler::compile(None, &ast, &mut registry)?;
     Ok(registry)
 }
+
+fn run(src: &str) -> Result<Value, Error> {
+    let tokens = scan(src)?;
+    let mut registry = HashMap::new();
+    let ast = ast_compiler::compile(tokens)?;
+    bytecode_compiler::compile(None, &ast, &mut registry)?;
+    interpret(&registry, "main").map_err(Error::from)
+}
diff --git a/src/main.rs b/src/main.rs
index 9eb235c..9056623 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,4 +1,4 @@
-use axum::extract::{Path, State};
+use axum::extract::{State};
 use axum::http::StatusCode;
 use axum::routing::get;
 use axum::{Json, Router};
@@ -9,12 +9,13 @@ use crudlang::scanner::scan;
 use crudlang::vm::{interpret, interpret_async};
 use std::collections::HashMap;
 use std::fs;
-use std::hash::Hash;
 use std::sync::Arc;
 use walkdir::WalkDir;
+use crudlang::errors::Error;
+use crudlang::errors::Error::Platform;
 
 #[tokio::main]
-async fn main() -> anyhow::Result<()> {
+async fn main() -> Result<(), crudlang::errors::Error> {
     tracing_subscriber::fmt::init();
 
     let mut paths = HashMap::new();
@@ -23,12 +24,12 @@ async fn main() -> anyhow::Result<()> {
         let path = entry.path();
         if path.is_file() && path.ends_with("web.crud") {
             print!("compiling {:?}: ", path);
-            let source = fs::read_to_string(path)?;
+            let source = fs::read_to_string(path).map_err(map_underlying())?;
             let tokens = scan(&source)?;
             match ast_compiler::compile(tokens) {
                 Ok(statements) => {
                     let path = path
-                        .strip_prefix("source")?
+                        .strip_prefix("source").map_err(|e|Platform(e.to_string()))?
                         .to_str()
                         .unwrap()
                         .replace(".crud", "");
@@ -58,13 +59,17 @@ async fn main() -> anyhow::Result<()> {
                 get(handle_get).with_state(state.clone()),
             );
         }
-        let listener = tokio::net::TcpListener::bind("0.0.0.0:3000").await?;
-        println!("listening on {}", listener.local_addr()?);
-        axum::serve(listener, app).await?;
+        let listener = tokio::net::TcpListener::bind("0.0.0.0:3000").await.map_err(map_underlying())?;
+        println!("listening on {}", listener.local_addr().map_err(map_underlying())?);
+        axum::serve(listener, app).await.map_err(map_underlying())?;
     }
     Ok(())
 }
 
+fn map_underlying() -> fn(std::io::Error) -> Error {
+    |e| Error::Platform(e.to_string())
+}
+
 #[derive(Clone)]
 struct AppState {
     name: String,
diff --git a/src/scanner.rs b/src/scanner.rs
index bcb1c22..c99fbe0 100644
--- a/src/scanner.rs
+++ b/src/scanner.rs
@@ -1,4 +1,3 @@
-use anyhow::anyhow;
 use crate::tokens::TokenType::{BitXor, FloatingPoint, Integer};
 use crate::{
     keywords,
@@ -7,8 +6,10 @@ use crate::{
         TokenType::{self},
     },
 };
+use crate::errors::CompilerError;
+use crate::errors::CompilerError::{IllegalCharLength, UnexpectedIdentifier, Unterminated};
 
-pub fn scan(source: &str) -> anyhow::Result<Vec<Token>> {
+pub fn scan(source: &str) -> Result<Vec<Token>, CompilerError> {
     let scanner = Scanner {
         chars: source.chars().collect(),
         current: 0,
@@ -21,7 +22,7 @@ pub fn scan(source: &str) -> anyhow::Result<Vec<Token>> {
 }
 
 impl Scanner {
-    fn scan(mut self) -> anyhow::Result<Vec<Token>> {
+    fn scan(mut self) -> Result<Vec<Token>, CompilerError> {
         while !self.is_at_end() {
             self.start = self.current;
             self.scan_token()?;
@@ -31,7 +32,7 @@ impl Scanner {
         Ok(self.tokens)
     }
 
-    fn scan_token(&mut self) -> anyhow::Result<()>{
+    fn scan_token(&mut self) -> Result<(),CompilerError> {
         let c = self.advance();
         if self.new_line && (c == ' ' || c == '\t') {
             self.add_token(TokenType::Indent);
@@ -138,7 +139,7 @@ impl Scanner {
                     } else if is_alpha(c) {
                         self.identifier();
                     } else {
-                        return Err(anyhow!("Unexpected identifier at line {}", self.line));
+                        return Err(UnexpectedIdentifier(self.line));
                     }
                 }
             }
@@ -173,13 +174,13 @@ impl Scanner {
         self.add_token_with_value(if has_dot { FloatingPoint } else { Integer }, value);
     }
 
-    fn char(&mut self) -> anyhow::Result<()>{
+    fn char(&mut self) -> Result<(), CompilerError>{
         while self.peek() != '\'' && !self.is_at_end() {
             self.advance();
         }
 
         if self.is_at_end() {
-            return Err(anyhow!("Unterminated char at {}", self.line))
+            return Err(Unterminated("char", self.line))
         }
 
         self.advance();
@@ -188,13 +189,13 @@ impl Scanner {
             .iter()
             .collect();
         if value.len() != 1 {
-            return Err(anyhow!("Illegal char length for {} at line {}", value, self.line))
+            return Err(IllegalCharLength(value, self.line))
         }
         self.add_token_with_value(TokenType::Char, value);
         Ok(())
     }
 
-    fn string(&mut self) -> anyhow::Result<()>{
+    fn string(&mut self) -> Result<(),CompilerError> {
         while self.peek() != '"' && !self.is_at_end() {
             if self.peek() == '\n' {
                 self.line += 1;
@@ -203,7 +204,7 @@ impl Scanner {
         }
 
         if self.is_at_end() {
-            return Err(anyhow!("Unterminated string at {}", self.line))
+            return Err(Unterminated("string", self.line))
         }
 
         self.advance();
diff --git a/src/value.rs b/src/value.rs
index ffeb772..cd0ca83 100644
--- a/src/value.rs
+++ b/src/value.rs
@@ -1,10 +1,10 @@
-use anyhow::anyhow;
 use chrono::{DateTime, Utc};
 use std::cmp::Ordering;
 use std::collections::HashMap;
 use std::fmt::{Display, Formatter};
 use std::hash::{Hash, Hasher};
 use std::ops::{Add, BitAnd, BitOr, BitXor, Div, Mul, Neg, Not, Shl, Shr, Sub};
+use crate::errors::ValueError;
 
 #[derive(Debug, Clone)]
 pub struct Object {
@@ -143,7 +143,7 @@ fn to_string(f: &mut Formatter, map: &HashMap<Value, Value>) -> std::fmt::Result
 }
 
 impl Neg for &Value {
-    type Output = anyhow::Result<Value>;
+    type Output = Result<Value, ValueError>;
 
     fn neg(self) -> Self::Output {
         match self {
@@ -151,13 +151,13 @@ impl Neg for &Value {
             Value::I64(i) => Ok(Value::I64(-i)),
             Value::F32(i) => Ok(Value::F32(-i)),
             Value::F64(i) => Ok(Value::F64(-i)),
-            _ => Err(anyhow!("Cannot negate")),
+            _ => Err(ValueError::Some("Cannot negate")),
         }
     }
 }
 
 impl Add<&Value> for &Value {
-    type Output = anyhow::Result<Value>;
+    type Output = Result<Value, ValueError>;
 
     fn add(self, rhs: &Value) -> Self::Output {
         if let Value::List(s) = self {
@@ -189,14 +189,14 @@ impl Add<&Value> for &Value {
                 }
                 (Value::String(s1), Value::Map(m)) => Ok(Value::String(format!("{}{:?}", s1, m))),
                 //enum?
-                _ => Err(anyhow!("Cannot add")),
+                _ => Err(ValueError::Some("Cannot add")),
             }
         }
     }
 }
 
 impl Sub<&Value> for &Value {
-    type Output = anyhow::Result<Value>;
+    type Output = Result<Value, ValueError>;
 
     fn sub(self, rhs: &Value) -> Self::Output {
         match (self, rhs) {
@@ -207,13 +207,13 @@ impl Sub<&Value> for &Value {
             (Value::F32(a), Value::F32(b)) => Ok(Value::F32(a - b)),
             (Value::F64(a), Value::F64(b)) => Ok(Value::F64(a - b)),
             //enum?
-            _ => Err(anyhow!("Cannot subtract")),
+            _ => Err(ValueError::Some("Cannot subtract")),
         }
     }
 }
 
 impl Mul<&Value> for &Value {
-    type Output = anyhow::Result<Value>;
+    type Output = Result<Value, ValueError>;
 
     fn mul(self, rhs: &Value) -> Self::Output {
         match (self, rhs) {
@@ -223,13 +223,13 @@ impl Mul<&Value> for &Value {
             (Value::U64(a), Value::U64(b)) => Ok(Value::U64(a * b)),
             (Value::F32(a), Value::F32(b)) => Ok(Value::F32(a * b)),
             (Value::F64(a), Value::F64(b)) => Ok(Value::F64(a * b)),
-            _ => Err(anyhow!("Cannot multiply")),
+            _ => Err(ValueError::Some("Cannot multiply")),
         }
     }
 }
 
 impl Div<&Value> for &Value {
-    type Output = anyhow::Result<Value>;
+    type Output = Result<Value, ValueError>;
 
     fn div(self, rhs: &Value) -> Self::Output {
         match (self, rhs) {
@@ -239,52 +239,52 @@ impl Div<&Value> for &Value {
             (Value::U64(a), Value::U64(b)) => Ok(Value::U64(a / b)),
             (Value::F32(a), Value::F32(b)) => Ok(Value::F32(a / b)),
             (Value::F64(a), Value::F64(b)) => Ok(Value::F64(a / b)),
-            _ => Err(anyhow!("Cannot divide")),
+            _ => Err(ValueError::Some("Cannot divide")),
         }
     }
 }
 
 impl BitAnd<&Value> for &Value {
-    type Output = anyhow::Result<Value>;
+    type Output = Result<Value, ValueError>;
     fn bitand(self, rhs: &Value) -> Self::Output {
         match (self, rhs) {
             (Value::I32(a), Value::I32(b)) => Ok(Value::I32(a & b)),
             (Value::I64(a), Value::I64(b)) => Ok(Value::I64(a & b)),
             (Value::U32(a), Value::U32(b)) => Ok(Value::U32(a & b)),
             (Value::U64(a), Value::U64(b)) => Ok(Value::U64(a & b)),
-            _ => Err(anyhow!("Cannot do bitwise-and on")),
+            _ => Err(ValueError::Some("Cannot do bitwise-and on")),
         }
     }
 }
 
 impl BitOr<&Value> for &Value {
-    type Output = anyhow::Result<Value>;
+    type Output = Result<Value, ValueError>;
     fn bitor(self, rhs: &Value) -> Self::Output {
         match (self, rhs) {
             (Value::I32(a), Value::I32(b)) => Ok(Value::I32(a | b)),
             (Value::I64(a), Value::I64(b)) => Ok(Value::I64(a | b)),
             (Value::U32(a), Value::U32(b)) => Ok(Value::U32(a | b)),
             (Value::U64(a), Value::U64(b)) => Ok(Value::U64(a | b)),
-            _ => Err(anyhow!("Cannot do bitwise-or on")),
+            _ => Err(ValueError::Some("Cannot do bitwise-or on")),
         }
     }
 }
 
 impl BitXor<&Value> for &Value {
-    type Output = anyhow::Result<Value>;
+    type Output = Result<Value, ValueError>;
     fn bitxor(self, rhs: &Value) -> Self::Output {
         match (self, rhs) {
             (Value::I32(a), Value::I32(b)) => Ok(Value::I32(a ^ b)),
             (Value::I64(a), Value::I64(b)) => Ok(Value::I64(a ^ b)),
             (Value::U32(a), Value::U32(b)) => Ok(Value::U32(a ^ b)),
             (Value::U64(a), Value::U64(b)) => Ok(Value::U64(a ^ b)),
-            _ => Err(anyhow!("Cannot do bitwise-xor on")),
+            _ => Err(ValueError::Some("Cannot do bitwise-xor on")),
         }
     }
 }
 
 impl Not for &Value {
-    type Output = anyhow::Result<Value>;
+    type Output = Result<Value, ValueError>;
 
     fn not(self) -> Self::Output {
         match self {
@@ -293,33 +293,33 @@ impl Not for &Value {
             Value::I64(i64) => Ok(Value::I64(!i64)),
             Value::U32(u32) => Ok(Value::U32(!u32)),
             Value::U64(u64) => Ok(Value::U64(!u64)),
-            _ => Err(anyhow!("Cannot calculate not")),
+            _ => Err(ValueError::Some("Cannot calculate not")),
         }
     }
 }
 
 impl Shl<&Value> for &Value {
-    type Output = anyhow::Result<Value>;
+    type Output = Result<Value, ValueError>;
     fn shl(self, rhs: &Value) -> Self::Output {
         match (self, rhs) {
             (Value::I32(a), Value::I32(b)) => Ok(Value::I32(a << b)),
             (Value::I64(a), Value::I64(b)) => Ok(Value::I64(a << b)),
             (Value::U32(a), Value::U32(b)) => Ok(Value::U32(a << b)),
             (Value::U64(a), Value::U64(b)) => Ok(Value::U64(a << b)),
-            _ => Err(anyhow!("Cannot shift left on")),
+            _ => Err(ValueError::Some("Cannot shift left on")),
         }
     }
 }
 
 impl Shr<&Value> for &Value {
-    type Output = anyhow::Result<Value>;
+    type Output = Result<Value, ValueError>;
     fn shr(self, rhs: &Value) -> Self::Output {
         match (self, rhs) {
             (Value::I32(a), Value::I32(b)) => Ok(Value::I32(a >> b)),
             (Value::I64(a), Value::I64(b)) => Ok(Value::I64(a >> b)),
             (Value::U32(a), Value::U32(b)) => Ok(Value::U32(a >> b)),
             (Value::U64(a), Value::U64(b)) => Ok(Value::U64(a >> b)),
-            _ => Err(anyhow!("Cannot shift right on")),
+            _ => Err(ValueError::Some("Cannot shift right on")),
         }
     }
 }
@@ -337,19 +337,19 @@ impl PartialEq for Value {
             (Value::String(a), Value::String(b)) => a == b,
             (Value::Char(a), Value::Char(b)) => a == b,
             (Value::Date(a), Value::Date(b)) => a == b,
-            // (Value::List(a), Value::List(b)) => a == b,
-            // (Value::Map(a), Value::Map(b)) => {
-            //     let mut equal = true;
-            //     for (k, v) in a.iter() {
-            //         if !b.contains_key(k) || b.get(k).unwrap() != v {
-            //             //safe unwrap
-            //             equal = false;
-            //             break;
-            //         }
-            //     }
-            //     equal
-            // }
-            // struct?
+            (Value::List(a), Value::List(b)) => a == b,
+            (Value::Map(a), Value::Map(b)) => {
+                let mut equal = true;
+                for (k, v) in a.iter() {
+                    if !b.contains_key(k) || b.get(k).unwrap() != v {
+                        //safe unwrap
+                        equal = false;
+                        break;
+                    }
+                }
+                equal
+            }
+            // TODO objects
             _ => false, //?
         }
     }
diff --git a/src/vm.rs b/src/vm.rs
index d9a2876..8e42177 100644
--- a/src/vm.rs
+++ b/src/vm.rs
@@ -1,6 +1,7 @@
 use crate::chunk::Chunk;
+use crate::errors::RuntimeError::{Something};
+use crate::errors::{RuntimeError, ValueError};
 use crate::value::Value;
-use anyhow::anyhow;
 use std::collections::HashMap;
 use tracing::debug;
 
@@ -11,9 +12,8 @@ macro_rules! define_var {
         if let Value::$variant(_) = value {
             $self.local_vars.insert(name, value);
         } else {
-            return Err(anyhow!(
-                concat!("Expected ", stringify!($variant), ", got {:?}"),
-                value
+            return Err(RuntimeError::Expected(
+                 stringify!($variant), stringify!(value),
             ));
         }
     }};
@@ -27,7 +27,7 @@ pub struct Vm<'a> {
     registry: &'a HashMap<String, Chunk>,
 }
 
-pub fn interpret(registry: &HashMap<String, Chunk>, function: &str) -> anyhow::Result<Value> {
+pub fn interpret(registry: &HashMap<String, Chunk>, function: &str) -> Result<Value, RuntimeError> {
     let chunk = registry.get(function).unwrap().clone();
     // for (key,value) in registry.iter() {
     //     println!("{}", key);
@@ -43,7 +43,7 @@ pub fn interpret(registry: &HashMap<String, Chunk>, function: &str) -> anyhow::R
     vm.run(&chunk, vec![])
 }
 
-pub async fn interpret_async(registry: &HashMap<String, Chunk>, function: &str) -> anyhow::Result<Value> {
+pub async fn interpret_async(registry: &HashMap<String, Chunk>, function: &str) -> Result<Value, RuntimeError> {
     let chunk = registry.get(function).unwrap().clone();
     let mut vm = Vm {
         ip: 0,
@@ -55,7 +55,7 @@ pub async fn interpret_async(registry: &HashMap<String, Chunk>, function: &str)
     vm.run(&chunk, vec![])
 }
 
-pub fn interpret_function(chunk: &Chunk, args: Vec<Value>) -> anyhow::Result<Value> {
+pub fn interpret_function(chunk: &Chunk, args: Vec<Value>) -> Result<Value, RuntimeError> {
     let mut vm = Vm {
         ip: 0,
         stack: vec![],
@@ -67,13 +67,13 @@ pub fn interpret_function(chunk: &Chunk, args: Vec<Value>) -> anyhow::Result<Val
 }
 
 impl <'a> Vm<'a> {
-    fn run(&mut self, chunk: &Chunk, args: Vec<Value>) -> anyhow::Result<Value> {
+    fn run(&mut self, chunk: &Chunk, args: Vec<Value>) -> Result<Value, RuntimeError> {
         for arg in args {
             self.push(arg);
         }
         loop {
             if self.error_occurred {
-                return Err(anyhow!("Error occurred"));
+                return Err(Something);
             }
             debug!("{:?}", self.stack);
             let opcode = chunk.code[self.ip];
@@ -91,14 +91,14 @@ impl <'a> Vm<'a> {
                     if let (Value::Bool(a), Value::Bool(b)) = (a, b) {
                         Ok(Value::Bool(*a && *b))
                     } else {
-                        Err(anyhow!("Cannot and"))
+                        Err(ValueError::Some("Cannot and"))
                     }
                 }),
                 OP_OR => binary_op(self, |a, b| {
                     if let (Value::Bool(a), Value::Bool(b)) = (a, b) {
                         Ok(Value::Bool(*a || *b))
                     } else {
-                        Err(anyhow!("Cannot compare"))
+                        Err(ValueError::Some("Cannot compare"))
                     }
                 }),
                 OP_NOT => unary_op(self, |a| !a),
@@ -210,7 +210,7 @@ impl <'a> Vm<'a> {
     }
 }
 
-fn binary_op(vm: &mut Vm, op: impl Fn(&Value, &Value) -> anyhow::Result<Value> + Copy) {
+fn binary_op(vm: &mut Vm, op: impl Fn(&Value, &Value) -> Result<Value, ValueError>  + Copy) {
     let b = vm.pop();
     let a = vm.pop();
 
@@ -218,13 +218,13 @@ fn binary_op(vm: &mut Vm, op: impl Fn(&Value, &Value) -> anyhow::Result<Value> +
     match result {
         Ok(result) => vm.push(result),
         Err(e) => {
-            println!("Error: {} {:?} and {:?}", e.to_string(), a, b);
             vm.error_occurred = true;
+            println!("Error: {} {:?} and {:?}", e.to_string(), a, b);
         }
     }
 }
 
-fn unary_op(stack: &mut Vm, op: impl Fn(&Value) -> anyhow::Result<Value> + Copy) {
+fn unary_op(stack: &mut Vm, op: impl Fn(&Value) -> Result<Value, ValueError>  + Copy) {
     let a = stack.pop();
     let result = op(&a);
     match result {