diff --git a/src/tokens/function.rs b/src/tokens/function.rs
new file mode 100644
index 0000000..e6eac16
--- /dev/null
+++ b/src/tokens/function.rs
@@ -0,0 +1,152 @@
+use std::collections::VecDeque;
+
+use crate::tokens::Token;
+use crate::tokens::Operator;
+//use crate::quantity::Quantity;
+
+
+#[derive(Debug)]
+#[derive(Copy, Clone)]
+pub enum Function {
+	Abs,
+	Floor,
+	Ceil,
+	Round,
+	
+	// TODO: Add arbitrary log
+	NaturalLog,
+	TenLog,
+
+	Sin,
+	Cos,
+	Tan,
+	Asin,
+	Acos,
+	Atan,
+	Csc,
+	Sec,
+	Cot,
+
+	Sinh,
+	Cosh,
+	Tanh,
+	Asinh,
+	Acosh,
+	Atanh,
+	Csch,
+	Sech,
+	Coth,
+}
+
+impl Function {
+	pub fn to_string(&self) -> String {
+		match self {
+			Function::Abs => { String::from("abs") },
+			Function::Floor => { String::from("floor") },
+			Function::Ceil => { String::from("ceil") },
+			Function::Round => { String::from("round") },
+			Function::NaturalLog => { String::from("ln") },
+			Function::TenLog => { String::from("log") },
+			Function::Sin => { String::from("sin") },
+			Function::Cos => { String::from("cos") },
+			Function::Tan => { String::from("tan") },
+			Function::Asin => { String::from("asin") },
+			Function::Acos => { String::from("acos") },
+			Function::Atan => { String::from("atan") },
+			Function::Csc => { String::from("csc") },
+			Function::Sec => { String::from("sec") },
+			Function::Cot => { String::from("cot") },
+			Function::Sinh => { String::from("sinh") },
+			Function::Cosh => { String::from("cosh") },
+			Function::Tanh => { String::from("tanh") },
+			Function::Asinh => { String::from("asinh") },
+			Function::Acosh => { String::from("acosh") },
+			Function::Atanh => { String::from("atanh") },
+			Function::Csch => { String::from("csch") },
+			Function::Sech => { String::from("sech") },
+			Function::Coth => { String::from("coth") },
+		}
+	}
+
+	pub fn apply(&self, args: &VecDeque<Token>) -> Result<Token, ()> {
+		if args.len() != 1 {panic!()};
+		let a = args[0].as_number();
+		let Token::Number(q) = a else {panic!()};
+
+		match self {
+			Function::Abs => { return Ok(Token::Number(q.abs())); },
+			Function::Floor => { return Ok(Token::Number(q.floor())); },
+			Function::Ceil => { return Ok(Token::Number(q.ceil())); },
+			Function::Round => { return Ok(Token::Number(q.round())); },
+
+			Function::NaturalLog => { return Ok(Token::Number(q.ln())); },
+			Function::TenLog => { return Ok(Token::Number(q.log10())); },
+
+			Function::Sin => { return Ok(Token::Number(q.sin())); },
+			Function::Cos => { return Ok(Token::Number(q.cos())); },
+			Function::Tan => { return Ok(Token::Number(q.tan())); },
+			Function::Asin => { return Ok(Token::Number(q.asin())); },
+			Function::Acos => { return Ok(Token::Number(q.acos())); },
+			Function::Atan => { return Ok(Token::Number(q.atan())); },
+
+			Function::Csc => {
+				return Ok(
+					Token::Operator(
+						Operator::Flip,
+						VecDeque::from(vec!(Token::Number(q.sin())))
+					).eval()?
+				);
+			},
+			Function::Sec => {
+				return Ok(
+					Token::Operator(
+						Operator::Flip,
+						VecDeque::from(vec!(Token::Number(q.cos())))
+					).eval()?
+				);
+			},
+			Function::Cot => {
+				return Ok(
+					Token::Operator(
+						Operator::Flip,
+						VecDeque::from(vec!(Token::Number(q.tan())))
+					).eval()?
+				);
+			},
+
+
+			Function::Sinh => { return Ok(Token::Number(q.sinh())); },
+			Function::Cosh => { return Ok(Token::Number(q.cosh())); },
+			Function::Tanh => { return Ok(Token::Number(q.tanh())); },
+			Function::Asinh => { return Ok(Token::Number(q.asinh())); },
+			Function::Acosh => { return Ok(Token::Number(q.acosh())); },
+			Function::Atanh => { return Ok(Token::Number(q.atanh())); },
+
+			Function::Csch => {
+				return Ok(
+					Token::Operator(
+						Operator::Flip,
+						VecDeque::from(vec!(Token::Number(q.sinh())))
+					).eval()?
+				);
+			},
+			Function::Sech => {
+				return Ok(
+					Token::Operator(
+						Operator::Flip,
+						VecDeque::from(vec!(Token::Number(q.cosh())))
+					).eval()?
+				);
+			},
+			Function::Coth => {
+				return Ok(
+					Token::Operator(
+						Operator::Flip,
+						VecDeque::from(vec!(Token::Number(q.tanh())))
+					).eval()?
+				);
+			},
+
+		}
+	}
+}
diff --git a/src/tokens/mod.rs b/src/tokens/mod.rs
new file mode 100644
index 0000000..3924e27
--- /dev/null
+++ b/src/tokens/mod.rs
@@ -0,0 +1,74 @@
+use std::collections::VecDeque;
+
+mod function;
+mod operator;
+
+pub use crate::tokens::function::Function;
+pub use crate::tokens::operator::Operator;
+
+
+use crate::quantity::Quantity;
+
+/// Tokens represent logical objects in an expession.
+/// 
+/// Tokens starting with `Pre*` are intermediate tokens, and
+/// will never show up in a fully-parsed expression tree.
+#[derive(Debug)]
+#[derive(Clone)]
+pub enum Token {
+	Number(Quantity),
+
+	Constant(Quantity, String),
+
+	Operator(
+		Operator,
+		VecDeque<Token>
+	),
+}
+
+impl Token {
+
+	pub fn print(&self) -> String {
+		match self {
+			Token::Number(v) => v.to_string(),
+			Token::Constant(_,s) => s.clone(),
+			Token::Operator(o,a) => o.print(a)
+		}
+	}
+
+	#[inline(always)]
+	pub fn get_args(&self) -> Option<&VecDeque<Token>> {
+		match self {
+			Token::Operator(_, ref a) => Some(a),
+			_ => None
+		}
+	}
+
+	#[inline(always)]
+	pub fn get_args_mut(&mut self) -> Option<&mut VecDeque<Token>> {
+		match self {
+			Token::Operator(_, ref mut a) => Some(a),
+			_ => None
+		}
+	}
+
+	#[inline(always)]
+	pub fn eval(&self) -> Result<Token, ()> {
+		Ok(match self {
+			Token::Number(_) => { self.clone() },
+			Token::Constant(v,_) => { Token::Number(v.clone()) },
+			Token::Operator(o,v) => { o.apply(&v)? }
+		})
+	}
+
+	// Temporary solution
+	#[inline(always)]
+	pub fn as_number(&self) -> Token {
+		match self {
+			Token::Number(v) => { Token::Number(v.clone()) },
+			Token::Constant(v,_) => { Token::Number(v.clone()) },
+			_ => panic!()
+		}
+	}
+
+}
\ No newline at end of file
diff --git a/src/tokens.rs b/src/tokens/operator.rs
similarity index 66%
rename from src/tokens.rs
rename to src/tokens/operator.rs
index 5478909..5d852ec 100644
--- a/src/tokens.rs
+++ b/src/tokens/operator.rs
@@ -1,72 +1,10 @@
 use std::collections::VecDeque;
 use std::cmp::Ordering;
 
+use crate::tokens::Token;
+use crate::tokens::Function;
 use crate::quantity::Quantity;
 
-/// Tokens represent logical objects in an expession.
-/// 
-/// Tokens starting with `Pre*` are intermediate tokens, and
-/// will never show up in a fully-parsed expression tree.
-#[derive(Debug)]
-#[derive(Clone)]
-pub enum Token {
-	Number(Quantity),
-
-	Constant(Quantity, String),
-
-	Operator(
-		Operator,
-		VecDeque<Token>
-	),
-}
-
-impl Token {
-
-	pub fn print(&self) -> String {
-		match self {
-			Token::Number(v) => v.to_string(),
-			Token::Constant(_,s) => s.clone(),
-			Token::Operator(o,a) => o.print(a)
-		}
-	}
-
-	#[inline(always)]
-	pub fn get_args(&self) -> Option<&VecDeque<Token>> {
-		match self {
-			Token::Operator(_, ref a) => Some(a),
-			_ => None
-		}
-	}
-
-	#[inline(always)]
-	pub fn get_args_mut(&mut self) -> Option<&mut VecDeque<Token>> {
-		match self {
-			Token::Operator(_, ref mut a) => Some(a),
-			_ => None
-		}
-	}
-
-	#[inline(always)]
-	pub fn eval(&self) -> Result<Token, ()> {
-		Ok(match self {
-			Token::Number(_) => { self.clone() },
-			Token::Constant(v,_) => { Token::Number(v.clone()) },
-			Token::Operator(o,v) => { o.apply(&v)? }
-		})
-	}
-
-	// Temporary solution
-	#[inline(always)]
-	pub fn as_number(&self) -> Token {
-		match self {
-			Token::Number(v) => { Token::Number(v.clone()) },
-			Token::Constant(v,_) => { Token::Number(v.clone()) },
-			_ => panic!()
-		}
-	}
-
-}
-
 /// Operator types, in order of increasing priority.
 #[derive(Debug)]
 #[derive(Clone)]
@@ -112,153 +50,6 @@ impl PartialOrd for Operator {
 	}
 }
 
-#[derive(Debug)]
-#[derive(Copy, Clone)]
-pub enum Function {
-	Abs,
-	Floor,
-	Ceil,
-	Round,
-	
-	// TODO: Add arbitrary log
-	NaturalLog,
-	TenLog,
-
-	Sin,
-	Cos,
-	Tan,
-	Asin,
-	Acos,
-	Atan,
-	Csc,
-	Sec,
-	Cot,
-
-	Sinh,
-	Cosh,
-	Tanh,
-	Asinh,
-	Acosh,
-	Atanh,
-	Csch,
-	Sech,
-	Coth,
-}
-
-impl Function {
-	pub fn to_string(&self) -> String {
-		match self {
-			Function::Abs => { String::from("abs") },
-			Function::Floor => { String::from("floor") },
-			Function::Ceil => { String::from("ceil") },
-			Function::Round => { String::from("round") },
-			Function::NaturalLog => { String::from("ln") },
-			Function::TenLog => { String::from("log") },
-			Function::Sin => { String::from("sin") },
-			Function::Cos => { String::from("cos") },
-			Function::Tan => { String::from("tan") },
-			Function::Asin => { String::from("asin") },
-			Function::Acos => { String::from("acos") },
-			Function::Atan => { String::from("atan") },
-			Function::Csc => { String::from("csc") },
-			Function::Sec => { String::from("sec") },
-			Function::Cot => { String::from("cot") },
-			Function::Sinh => { String::from("sinh") },
-			Function::Cosh => { String::from("cosh") },
-			Function::Tanh => { String::from("tanh") },
-			Function::Asinh => { String::from("asinh") },
-			Function::Acosh => { String::from("acosh") },
-			Function::Atanh => { String::from("atanh") },
-			Function::Csch => { String::from("csch") },
-			Function::Sech => { String::from("sech") },
-			Function::Coth => { String::from("coth") },
-		}
-	}
-
-	pub fn apply(&self, args: &VecDeque<Token>) -> Result<Token, ()> {
-		if args.len() != 1 {panic!()};
-		let a = args[0].as_number();
-		let Token::Number(q) = a else {panic!()};
-
-		match self {
-			Function::Abs => { return Ok(Token::Number(q.abs())); },
-			Function::Floor => { return Ok(Token::Number(q.floor())); },
-			Function::Ceil => { return Ok(Token::Number(q.ceil())); },
-			Function::Round => { return Ok(Token::Number(q.round())); },
-
-			Function::NaturalLog => { return Ok(Token::Number(q.ln())); },
-			Function::TenLog => { return Ok(Token::Number(q.log10())); },
-
-			Function::Sin => { return Ok(Token::Number(q.sin())); },
-			Function::Cos => { return Ok(Token::Number(q.cos())); },
-			Function::Tan => { return Ok(Token::Number(q.tan())); },
-			Function::Asin => { return Ok(Token::Number(q.asin())); },
-			Function::Acos => { return Ok(Token::Number(q.acos())); },
-			Function::Atan => { return Ok(Token::Number(q.atan())); },
-
-			Function::Csc => {
-				return Ok(
-					Token::Operator(
-						Operator::Flip,
-						VecDeque::from(vec!(Token::Number(q.sin())))
-					).eval()?
-				);
-			},
-			Function::Sec => {
-				return Ok(
-					Token::Operator(
-						Operator::Flip,
-						VecDeque::from(vec!(Token::Number(q.cos())))
-					).eval()?
-				);
-			},
-			Function::Cot => {
-				return Ok(
-					Token::Operator(
-						Operator::Flip,
-						VecDeque::from(vec!(Token::Number(q.tan())))
-					).eval()?
-				);
-			},
-
-
-			Function::Sinh => { return Ok(Token::Number(q.sinh())); },
-			Function::Cosh => { return Ok(Token::Number(q.cosh())); },
-			Function::Tanh => { return Ok(Token::Number(q.tanh())); },
-			Function::Asinh => { return Ok(Token::Number(q.asinh())); },
-			Function::Acosh => { return Ok(Token::Number(q.acosh())); },
-			Function::Atanh => { return Ok(Token::Number(q.atanh())); },
-
-			Function::Csch => {
-				return Ok(
-					Token::Operator(
-						Operator::Flip,
-						VecDeque::from(vec!(Token::Number(q.sinh())))
-					).eval()?
-				);
-			},
-			Function::Sech => {
-				return Ok(
-					Token::Operator(
-						Operator::Flip,
-						VecDeque::from(vec!(Token::Number(q.cosh())))
-					).eval()?
-				);
-			},
-			Function::Coth => {
-				return Ok(
-					Token::Operator(
-						Operator::Flip,
-						VecDeque::from(vec!(Token::Number(q.tanh())))
-					).eval()?
-				);
-			},
-
-		}
-	}
-}
-
-
 impl Operator {
 
 	#[inline(always)]