diff --git a/complexpr/src/eval.rs b/complexpr/src/eval.rs
index d4ecaaf..75d9ba4 100644
--- a/complexpr/src/eval.rs
+++ b/complexpr/src/eval.rs
@@ -36,6 +36,10 @@ impl From<RuntimeError> for Unwind {
     }
 }
 
+//
+// Statements
+//
+
 fn unwrap_ident_token(tok: &Token) -> &Rc<str> {
     if let Token { ty: TokenType::Ident(s),.. } = tok {
         s
@@ -128,21 +132,33 @@ pub fn eval_stmt(stmt: &Stmt, env: EnvRef) -> Result<(), Unwind> {
     Ok(())
 }
 
+//
+// Expressions
+//
+
 pub fn eval_expr(expr: &Expr, env: EnvRef) -> Result<Value, RuntimeError> {
     match expr {
         Expr::Literal { value } => Ok(eval_literal(value)),
         Expr::Ident { value } => eval_ident(value, env),
         Expr::Binary { lhs, rhs, op } => match op.ty.get_op_type() {
+            Some(OpType::Additive) 
+            | Some(OpType::Multiplicative) 
+            | Some(OpType::Exponential)
+            | Some(OpType::Comparison) => {
+                let l = eval_expr(lhs, env.clone())?;
+                let r = eval_expr(rhs, env)?;
+                eval_standard_binary(l, r, &op.ty, &op.pos)
+            },
             Some(OpType::Assignment) 
                 => eval_assignment(lhs, rhs, op, env),
-            Some(OpType::Additive) | Some(OpType::Multiplicative) | Some(OpType::Exponential)
-                => eval_arith(lhs, rhs, op, env),
             Some(OpType::LogicalAnd) | Some(OpType::LogicalOr)
                 => eval_boolean(lhs, rhs, op, env),
-            Some(OpType::Comparison)
-                => eval_comp(lhs, rhs, op, env),
-            Some(OpType::Pipeline)
-                => eval_pipeline(lhs, rhs, op, env),
+            Some(OpType::Pipeline) => {
+                let l = eval_expr(lhs, env.clone())?;
+                let r = eval_expr(rhs, env)?;
+                let f = r.as_func().map_err(|e| RuntimeError::new(e, op.pos.clone()))?;
+                eval_pipeline(l, f, op).map_err(exit_pipe(&op.pos))
+            }
             o => todo!("{:?}", o) // TODO other operations
         },
         Expr::Ternary { arg1, arg2, arg3, op } => eval_ternary(arg1, arg2, arg3, op, env),
@@ -152,6 +168,7 @@ pub fn eval_expr(expr: &Expr, env: EnvRef) -> Result<Value, RuntimeError> {
                 end.as_ref().map(|x| x.as_ref()), 
                 step.as_ref().map(|x| x.as_ref()), 
                 *incl, env),
+        Expr::BoxedInfix { func } => Ok(Value::Func(func.clone())),
         Expr::List { items } => {
             let mut list = Vec::with_capacity(items.len());
             for item in items {
@@ -275,10 +292,9 @@ pub fn eval_assignment(lhs: &Expr, rhs: &Expr, op: &Token, env: EnvRef) -> Resul
     }
 }
 
-pub fn eval_arith(lhs: &Expr, rhs: &Expr, op: &Token, env: EnvRef) -> Result<Value, RuntimeError> {
-    let l = eval_expr(lhs, env.clone())?;
-    let r = eval_expr(rhs, env)?;
-    match op.ty {
+pub fn eval_standard_binary(l: Value, r: Value, opty: &TokenType, pos: &Position) -> Result<Value, RuntimeError> {
+    let mk_err = || format!("Cannot compare {:?} with {:?}", l, r);
+    match opty {
         TokenType::Plus => &l + &r,
         TokenType::Minus => &l - &r,
         TokenType::Star => &l * &r,
@@ -286,35 +302,6 @@ pub fn eval_arith(lhs: &Expr, rhs: &Expr, op: &Token, env: EnvRef) -> Result<Val
         TokenType::Percent => &l % &r,
         TokenType::Caret => l.pow(&r),
         TokenType::DoubleSlash => l.fracdiv(&r),
-        _ => todo!()
-    }.map_err(|e| RuntimeError::new(e, op.pos.clone()))
-}
-
-pub fn eval_boolean(lhs: &Expr, rhs: &Expr, op: &Token, env: EnvRef) -> Result<Value, RuntimeError> {
-    let l = eval_expr(lhs, env.clone())?;
-    match op.ty {
-        TokenType::DoubleAmper => if l.truthy() {
-            eval_expr(rhs, env)
-        } else { 
-            Ok(l)
-        },
-        TokenType::DoublePipe => if !l.truthy() {
-            eval_expr(rhs, env)
-        } else { 
-            Ok(l)
-        },
-        _ => unreachable!()
-    }
-}
-
-pub fn eval_comp(lhs: &Expr, rhs: &Expr, op: &Token, env: EnvRef) -> Result<Value, RuntimeError> {
-    let l = eval_expr(lhs, env.clone())?;
-    let r = eval_expr(rhs, env)?;
-    let mk_err = || RuntimeError::new(
-        format!("Cannot compare {:?} with {:?}", l, r),
-        op.pos.clone()
-    );
-    match op.ty {
         TokenType::DoubleEqual => Ok(Value::Bool(l == r)),
         TokenType::BangEqual => Ok(Value::Bool(l != r)),
         TokenType::Greater => l.partial_cmp(&r)
@@ -333,6 +320,23 @@ pub fn eval_comp(lhs: &Expr, rhs: &Expr, op: &Token, env: EnvRef) -> Result<Valu
             .ok_or_else(mk_err)
             .map(|o| Value::from(o as i8)),
         _ => unreachable!()
+    }.map_err(|e| RuntimeError::new(e, pos.clone()))
+}
+
+pub fn eval_boolean(lhs: &Expr, rhs: &Expr, op: &Token, env: EnvRef) -> Result<Value, RuntimeError> {
+    let l = eval_expr(lhs, env.clone())?;
+    match op.ty {
+        TokenType::DoubleAmper => if l.truthy() {
+            eval_expr(rhs, env)
+        } else { 
+            Ok(l)
+        },
+        TokenType::DoublePipe => if !l.truthy() {
+            eval_expr(rhs, env)
+        } else { 
+            Ok(l)
+        },
+        _ => unreachable!()
     }
 }
 
@@ -371,16 +375,8 @@ fn mk_pipequestion_inner(f: Func, it: CIterator) -> Func {
     }
 }
 
-
-pub fn eval_pipeline(lhs: &Expr, rhs: &Expr, op: &Token, env: EnvRef) -> Result<Value, RuntimeError> {
-    let l = eval_expr(lhs, env.clone())?;
-    let r = eval_expr(rhs, env)?;
-    let f = r.as_func().map_err(|e| RuntimeError::new(e, op.pos.clone()))?;
-    eval_pipeline_inner(l, f, op).map_err(exit_pipe(&op.pos))
-}
-
 #[allow(clippy::needless_collect)] // collect is necesary to allow for rev() call
-fn eval_pipeline_inner(l: Value, r: &Func, op: &Token) -> Result<Value, RuntimeError> {
+fn eval_pipeline(l: Value, r: &Func, op: &Token) -> Result<Value, RuntimeError> {
     match op.ty {
         TokenType::PipePoint => r.call(vec![l]),
         TokenType::PipeColon => Ok(Value::Func(mk_pipecolon_inner(r.clone(), l.iter()?))),
diff --git a/complexpr/src/expr.rs b/complexpr/src/expr.rs
index ad30676..3146a85 100644
--- a/complexpr/src/expr.rs
+++ b/complexpr/src/expr.rs
@@ -1,6 +1,6 @@
 use std::fmt;
 
-use crate::{token::{Token, OpType}, Position, value::Type};
+use crate::{token::{Token, OpType}, Position, value::{Type, func::Func}};
 
 #[derive(Clone)]
 pub enum Stmt {
@@ -41,6 +41,7 @@ pub enum Expr {
     Ternary { arg1: Box<Expr>, arg2: Box<Expr>, arg3: Box<Expr>, op: Token },
     Unary { arg: Box<Expr>, op: Token },
     Range { start: Box<Expr>, end: Option<Box<Expr>>, step: Option<Box<Expr>>, incl: bool },
+    BoxedInfix { func: Func },
     Ident { value: Token },
     Literal { value: Token },
     List { items: Vec<Expr> },
@@ -57,6 +58,7 @@ impl fmt::Debug for Expr {
             Self::Ternary { arg1, arg2, arg3, op} => write!(f, "({:?} {:?} {:?} {:?})", op, arg1, arg2, arg3),
             Self::Unary { arg, op } => write!(f, "({:?} {:?})", op, arg),
             Self::Range { start, end, step, incl } => write!(f, "(range {:?}..{:?} step {:?} incl {:?})", start, end, step, incl),
+            Self::BoxedInfix { func } => write!(f, "(boxed-infix {:?})", func),
             Self::Ident { value } => write!(f, "(ident {:?})", value),
             Self::Literal { value } => write!(f, "(lit {:?})", value),
             Self::List { items } => write!(f, "(list {:?})", items),
diff --git a/complexpr/src/parser.rs b/complexpr/src/parser.rs
index 27dff76..3ac226a 100644
--- a/complexpr/src/parser.rs
+++ b/complexpr/src/parser.rs
@@ -1,4 +1,6 @@
-use crate::{token::{Token, TokenType, OpType}, ParserError, expr::{Stmt, Expr}, value};
+use std::rc::Rc;
+
+use crate::{token::{Token, TokenType, OpType}, ParserError, expr::{Stmt, Expr}, value::{self, func::Func}, eval::eval_standard_binary};
 
 pub struct Parser {
     tokens: Vec<Token>,
@@ -400,6 +402,7 @@ impl Parser {
         }
     }
 
+    // unary: !x, -x
     fn unary(&mut self) -> Result<Expr, ParserError> {
         self.err_on_eof()?;
         if matches!(self.peek().ty, TokenType::Bang | TokenType::Minus) {
@@ -410,6 +413,7 @@ impl Parser {
         }
     }
 
+    // function calls and array access
     fn fncall(&mut self) -> Result<Expr, ParserError> {
         let mut expr = self.expr_base()?;
         while !self.at_end() {
@@ -422,12 +426,14 @@ impl Parser {
         Ok(expr)
     }
 
+    // function call: a(b)
     fn fncall_inner(&mut self, expr: Expr) -> Result<Expr, ParserError> {
         let lparen = self.next();
         let args = self.commalist(TokenType::RParen, Self::assignment)?;
         Ok(Expr::FuncCall { func: Box::new(expr), args, pos: lparen.pos })
     }
 
+    // array index: a[b]
     fn arrindex_inner(&mut self, expr: Expr) -> Result<Expr, ParserError> {
         let lbrack = self.next();
         let index = self.assignment()?;
@@ -438,6 +444,7 @@ impl Parser {
         Ok(Expr::Index { lhs: Box::new(expr), index: Box::new(index), pos: lbrack.pos })
     }
 
+    // key-value pairs for maps
     fn kv_pair(&mut self) -> Result<(Expr, Expr), ParserError> {
         let key = self.assignment()?;
         self.err_on_eof()?;
@@ -449,6 +456,7 @@ impl Parser {
         Ok((key, value))
     }
 
+    // After infix operators, unary operators, function calls, and array indexes have been parsed
     fn expr_base(&mut self) -> Result<Expr, ParserError> {
         self.err_on_eof()?;
         let next = self.next();
@@ -457,10 +465,29 @@ impl Parser {
             | TokenType::Int(_) | TokenType::Float(_) | TokenType::ImFloat(_)
             | TokenType::String(_) | TokenType::Char(_)
         ) {
+            // A literal value
             Ok(Expr::Literal { value: next })
         } else if let TokenType::Ident(..) = next.ty {
+            // An identifier
             Ok(Expr::Ident { value: next })
         } else if next.ty == TokenType::LParen {
+            // Special case for "boxed infix operators"
+            if !self.at_end() && self.peek().ty.is_infix_op() {
+                let op = self.next();
+                self.err_on_eof()?;
+                if self.peek().ty != TokenType::RParen {
+                    return Err(self.mk_error("Expected right parenthesis after enclosed operator"))
+                }
+                self.next();
+                let func = Func::BuiltinClosure {
+                    arg_count: 2,
+                    func: Rc::new(move |args| {
+                        eval_standard_binary(args[0].clone(), args[1].clone(), &op.ty, &op.pos)
+                    })
+                };
+                return Ok(Expr::BoxedInfix { func })
+            }
+            // general case: parentheses as grouping symbols
             let expr = self.assignment()?;
             if self.at_end() || TokenType::RParen != self.next().ty {
                 Err(self.mk_error("Left parenthesis never closed"))
@@ -468,12 +495,15 @@ impl Parser {
                 Ok(expr)
             }
         } else if next.ty == TokenType::LBrack {
+            // list literal
             let items = self.commalist(TokenType::RBrack, Self::assignment)?;
             Ok(Expr::List { items })
         } else if next.ty == TokenType::LBrace {
+            // map literal
             let items = self.commalist(TokenType::RBrace, Self::kv_pair)?;
             Ok(Expr::Map { items })
         } else if next.ty == TokenType::Fn {
+            // anonymous (lambda) function definition
             self.err_on_eof()?;
             if !self.expect(TokenType::LParen).0 {
                 return Err(self.mk_error("Expected left parenthesis to start arguments list"))
diff --git a/complexpr/src/stdlib/mod.rs b/complexpr/src/stdlib/mod.rs
index 2948140..a779b9f 100644
--- a/complexpr/src/stdlib/mod.rs
+++ b/complexpr/src/stdlib/mod.rs
@@ -61,11 +61,11 @@ fn fn_copy(args: Vec<Value>) -> Result<Value, RuntimeError> {
 }
 
 fn fn_str(args: Vec<Value>) -> Result<Value, RuntimeError> {
-    Ok(Value::String(args[0].to_string()))
+    Ok(Value::from(args[0].to_string()))
 }
 
 fn fn_repr(args: Vec<Value>) -> Result<Value, RuntimeError> {
-    Ok(Value::String(args[0].repr()))
+    Ok(Value::from(args[0].repr()))
 }
 
 fn fn_ord(args: Vec<Value>) -> Result<Value, RuntimeError> {
diff --git a/complexpr/src/token.rs b/complexpr/src/token.rs
index cbf305d..6907ed6 100644
--- a/complexpr/src/token.rs
+++ b/complexpr/src/token.rs
@@ -66,8 +66,6 @@ impl TokenType {
             Self::DoubleAmper => Some(OpType::LogicalAnd),
             Self::DoublePipe => Some(OpType::LogicalOr),
 
-            Self::DoubleDot => Some(OpType::Range),
-
             _ => None
         }
     }
@@ -78,11 +76,21 @@ impl TokenType {
             _ => None
         }
     }
+
+    pub fn is_infix_op(&self) -> bool {
+        matches!(self.get_op_type(), Some(
+            OpType::Additive
+            | OpType::Multiplicative
+            | OpType::Exponential
+            | OpType::Comparison
+            // TODO | OpType::Pipeline
+        ))
+    }
 }
 
 #[derive(Clone,Copy,Debug,PartialEq,Eq)]
 pub enum OpType {
-    Assignment, Comparison, Pipeline, Additive, Multiplicative, Exponential, LogicalAnd, LogicalOr, Range
+    Assignment, Comparison, Pipeline, Additive, Multiplicative, Exponential, LogicalAnd, LogicalOr
 }
 
 impl OpType {
diff --git a/complexpr/src/value/mod.rs b/complexpr/src/value/mod.rs
index 784d417..7a27dee 100644
--- a/complexpr/src/value/mod.rs
+++ b/complexpr/src/value/mod.rs
@@ -1,5 +1,6 @@
 use std::{rc::Rc, collections::HashMap, ops::*, cmp::Ordering, cell::RefCell, hash::Hash, sync::atomic::{AtomicUsize, self}};
 
+use either::Either;
 use num_traits::{Zero, ToPrimitive, Pow};
 use strum::{EnumCount, EnumDiscriminants, EnumIter, IntoEnumIterator, AsRefStr};
 
@@ -42,6 +43,73 @@ pub fn generate_builtin_types() -> Vec<Type> {
     types
 }
 
+fn fmt_list(list: &Vec<Value>) -> String {
+    let mut result: String = "[".into();
+    for v in list {
+        result += &(v.repr() + ", ");
+    }
+    result.pop();
+    result.pop();
+    result + "]"
+}
+
+fn fmt_map(map: &HashMap<Value, Value>) -> String {
+    let mut result: String = "{".into();
+    for (k, v) in map {
+        result += &(k.repr() + ": " + &v.repr() + ", ");
+    }
+    result.pop();
+    result.pop();
+    result + "}"
+}
+
+enum EscapeResult { Char(char), Str(&'static str), String(String) }
+
+fn escape_char(c: char, is_char: bool) -> EscapeResult {
+    match c {
+        '\0' => EscapeResult::Str("\\0"),
+        '\n' => EscapeResult::Str("\\n"),
+        '\r' => EscapeResult::Str("\\r"),
+        '\t' => EscapeResult::Str("\\t"),
+        '\x1b' => EscapeResult::Str("\\e"),
+        '\\' if is_char => EscapeResult::Str("\\\\"),
+        '\'' if is_char => EscapeResult::Str("\\'"),
+        '"' if !is_char => EscapeResult::Str("\\\""),
+        _ if c.is_control() => {
+            if c <= '\u{ff}' {
+                EscapeResult::String(format!("\\x{:02x}", c as u32))
+            } else {
+                EscapeResult::String(format!("\\u{{{:06x}}}", c as u32))
+            }
+        }
+        _ => EscapeResult::Char(c)
+    }
+}
+
+fn repr_string(s: &str) -> String {
+    let mut result: String = "\"".into();
+    for c in s.chars() {
+        match escape_char(c, false) {
+            EscapeResult::Char(c) => result.push(c),
+            EscapeResult::Str(s) => result += s,
+            EscapeResult::String(s) => result += &s,
+        }
+    }
+    result.push('"');
+    result
+}
+
+fn repr_char(c: char) -> String {
+    let mut result: String = "'".into();
+    match escape_char(c, true) {
+        EscapeResult::Char(c) => result.push(c),
+        EscapeResult::Str(s) => result += s,
+        EscapeResult::String(s) => result += &s
+    }
+    result.push('\'');
+    result
+}
+
 #[derive(Clone, Debug)]
 pub struct CxprStruct {
     pub ty: Type,
@@ -91,52 +159,50 @@ impl Value {
                     Err("Only zero-argument functions can be used as iterators".into())
                 }
             },
-            v => Err(format!("{:?} is not iterable", v))
+            v => Err(format!("{} is not iterable", v.repr()))
         }
     }
 
     pub fn as_func(&self) -> Result<&Func, String> {
         match self {
             Value::Func(f) => Ok(f),
-            v => Err(format!("{:?} is not a function", v))
+            v => Err(format!("{} is not a function", v.repr()))
         }
     }
 
-    pub fn to_string(&self) -> Rc<str> {
+    pub fn to_string(&self) -> String {
         match self {
-            Self::Nil => Rc::from("nil"),
-            Self::Bool(b) => Rc::from(b.to_string()),
-            Self::Int(n) => Rc::from(n.to_string()),
-            Self::Float(f) => Rc::from(f.to_string()),
-            Self::Rational(r) => Rc::from(r.to_string()),
-            Self::Complex(z) => Rc::from(z.to_string()),
-            Self::Char(c) => Rc::from(c.to_string()),
-            Self::String(s) => s.clone(),
-            Self::List(l) => Rc::from(format!("{:?}", l)), // TODO fix
-            Self::Map(m) => Rc::from(format!("{:?}", m)), // TODO fix
-            Self::Type(t) => Rc::from(format!("<type {}>", t.name)),
-            Self::Func(Func::Builtin { name, func, .. }) => Rc::from(format!("<builtin fn {} at {:?}>", name, *func as *const ())),
-            Self::Func(Func::BuiltinClosure { .. }) => Rc::from(format!("<builtin anonymous fn>")),
+            Self::Nil => "nil".into(),
+            Self::Bool(b) => b.to_string(),
+            Self::Int(n) => n.to_string(),
+            Self::Float(f) => f.to_string(),
+            Self::Rational(r) => r.to_string(),
+            Self::Complex(z) => z.to_string(),
+            Self::Char(c) => c.to_string(),
+            Self::String(s) => s.as_ref().to_owned(),
+            Self::List(l) => fmt_list(&l.borrow()),
+            Self::Map(m) => fmt_map(&m.borrow()),
+            Self::Type(t) => format!("<type {}>", t.name),
+            Self::Func(Func::Builtin { name, func, .. }) => format!("<builtin fn {} at {:?}>", name, *func as *const ()),
+            Self::Func(Func::BuiltinClosure { .. }) => format!("<builtin anonymous fn>"),
             Self::Func(f @ Func::Partial { .. }) => match f.name() {
-                Some(name) => Rc::from(format!("<partial of fn {}>", name)),
-                None => Rc::from("<partial of anonymous fn>"),
+                Some(name) => format!("<partial of fn {}>", name),
+                None => "<partial of anonymous fn>".into(),
             }
             Self::Func(Func::Func { name, .. }) => match name {
-                Some(name) => Rc::from(format!("<fn {}>", name)),
-                None => Rc::from("<anonymous fn>"),
+                Some(name) => format!("<fn {}>", name),
+                None => "<anonymous fn>".into(),
             },
             Self::Data(_) => todo!(),
         }
     }
     
-    pub fn repr(&self) -> Rc<str> {
+    pub fn repr(&self) -> String {
         match self {
-            Self::Float(f) => Rc::from(format!("{:?}",f)),
-            Self::Rational(r) => Rc::from(r.numer().to_string() + "//" + &r.denom().to_string()),
-            Self::Char(c) => Rc::from(format!("'{}'", c)), // TODO escaping
-            Self::String(s) => Rc::from(format!("\"{}\"", s)), // TODO escaping
-            Self::List(l) => Rc::from(format!("{:?}", l.borrow())), // TODO fix
-            Self::Map(m) => Rc::from(format!("{:?}", m)), // TODO fix
+            Self::Float(f) => format!("{:?}",f),
+            Self::Rational(r) => r.numer().to_string() + "//" + &r.denom().to_string(),
+            Self::Char(c) => repr_char(*c),
+            Self::String(s) => repr_string(s),
             _ => self.to_string(),
         }
     }
@@ -148,17 +214,17 @@ impl Value {
                     .ok_or_else(|| format!("String index {} out of bounds for length {}", i, s.chars().count()))
                     .map(Value::Char),
                 Value::Int(i) => Err(format!("String index {} cannot be negative", i)),
-                _ => Err(format!("Cannot index {:?} with {:?}", self, idx))
+                _ => Err(format!("Cannot index {} with {}", self.repr(), idx.repr()))
             },
             Self::List(l) => match idx {
                 Value::Int(i) if *i >= 0 => l.borrow().get(*i as usize)
                     .ok_or_else(|| format!("List index {} out of bounds for length {}", i, l.borrow().len()))
                     .map(|v| v.clone()),
                 Value::Int(i) => Err(format!("List index {} cannot be negative", i)),
-                _ => Err(format!("Cannot index {:?} with {:?}", self, idx))
+                _ => Err(format!("Cannot index {} with {}", self.repr(), idx.repr()))
             }
-            Self::Map(m) => m.borrow().get(idx).cloned().ok_or_else(|| format!("Map does not contain key {:?}", idx)),
-            v => Err(format!("Cannot index into {:?}", v))
+            Self::Map(m) => m.borrow().get(idx).cloned().ok_or_else(|| format!("Map does not contain key {}", idx.repr())),
+            v => Err(format!("Cannot index into {}", v.repr()))
         }
     }
 
@@ -171,13 +237,13 @@ impl Value {
                 }
                 Value::Int(i) if *i >= 0 => Err(format!("List index {} out of bounds for length {}", i, l.borrow().len())),
                 Value::Int(i) => Err(format!("List index {} cannot be negative", i)),
-                _ => Err(format!("Cannot index {:?} with {:?}", self, idx))
+                _ => Err(format!("Cannot index {} with {}", self.repr(), idx.repr()))
             }
             Self::Map(m) => {
                 m.borrow_mut().insert(idx.clone(), value); 
                 Ok(())
             }
-            v => Err(format!("Cannot assign to index in {:?}", v))
+            v => Err(format!("Cannot assign to index in {}", v.repr()))
         }
     }
 
@@ -186,7 +252,7 @@ impl Value {
             Value::String(s) => Ok(s.len()),
             Value::List(l) => Ok(l.borrow().len()),
             Value::Map(m) => Ok(m.borrow().len()),
-            v => Err(format!("{:?} has no length", v))
+            v => Err(format!("{} has no length", v.repr()))
         }
     }
     
@@ -205,7 +271,7 @@ impl Value {
             (Rational(a), Int(b)) => Ok(Value::from(a/b)),
             (Int(a), Rational(b)) => Ok(Value::from(b.recip()*a)),
             (Rational(a), Rational(b)) => Ok(Value::from(a/b)),
-            (x,y) => Err(format!("Unsupported operation 'fracdiv' between {:?} and {:?}", x, y))
+            (x,y) => Err(format!("Unsupported operation 'fracdiv' between {} and {}", x.repr(), y.repr()))
         }
     }
     
@@ -400,7 +466,7 @@ macro_rules! impl_numeric_op {
                     (Rational(a), Complex(b))  => Ok(self::Complex::from(a.to_f64().ok_or(RATIO_CAST_FAIL)?).$fnname(b).into()),
                     (Complex(a),  Rational(b)) => Ok(a.$fnname(self::Complex::from(b.to_f64().ok_or(RATIO_CAST_FAIL)?)).into()),
                     (Complex(a),  Complex(b))  => Ok(a.$fnname(b).into()),
-                    (lhs, rhs) => Err(format!("Unsupported operation '{}' between {:?} and {:?}", stringify!($fnname), lhs, rhs))
+                    (lhs, rhs) => Err(format!("Unsupported operation '{}' between {} and {}", stringify!($fnname), lhs.repr(), rhs.repr()))
                 }
             }
         }
@@ -415,7 +481,7 @@ impl Neg for Value {
             Value::Float(a) => Ok(Value::Float(-a)),
             Value::Rational(a) => Ok(Value::Rational(-a)),
             Value::Complex(a) => Ok(Value::Complex(-a)),
-            _ => Err(format!("Unsupported operation 'neg' on {:?}", self))
+            _ => Err(format!("Unsupported operation 'neg' on {}", self.repr()))
         }
     }
 }
@@ -490,7 +556,7 @@ impl Pow<&Value> for &Value {
             (Rational(a), Complex(b))  => Ok(self::Complex::from(a.to_f64().ok_or(RATIO_CAST_FAIL)?).pow(b).into()),
             (Complex(a),  Rational(b)) => Ok(a.pow(self::Complex::from(b.to_f64().ok_or(RATIO_CAST_FAIL)?)).into()),
             (Complex(a),  Complex(b))  => Ok(a.pow(b).into()),
-            (lhs, rhs) => Err(format!("Unsupported operation 'pow' between {:?} and {:?}", lhs, rhs))
+            (lhs, rhs) => Err(format!("Unsupported operation 'pow' between {} and {}", lhs.repr(), rhs.repr()))
         }
     }
 }