Use rustfmt for some files

rustfmt.toml

@@ -0,0 +1 @@
+tab_spaces=2

src/evaluator.rs

@@ -1,13 +1,13 @@
-use decimal::d128;
-use crate::{Token, Number};
-use crate::units::{Unit, UnitType, convert, add, subtract, multiply, divide, modulo, pow};
-use crate::parser::AstNode;
-use crate::Operator::{Caret, Divide, Minus, Modulo, Multiply, Plus};
-use crate::Constant::{Pi, E};
-use crate::UnaryOperator::{Percent, Factorial};
-use crate::TextOperator::{To, Of};
-use crate::FunctionIdentifier::*;
 use crate::lookup::{lookup_factorial, lookup_named_number};
+use crate::parser::AstNode;
+use crate::units::{add, convert, divide, modulo, multiply, pow, subtract, Unit, UnitType};
+use crate::Constant::{Pi, E};
+use crate::FunctionIdentifier::*;
+use crate::Operator::{Caret, Divide, Minus, Modulo, Multiply, Plus};
+use crate::TextOperator::{Of, To};
+use crate::UnaryOperator::{Factorial, Percent};
+use crate::{Number, Token};
+use decimal::d128;
 
 /// Evaluate an [`AstNode`] into a [`Number`]
 pub fn evaluate(ast: &AstNode) -> Result<Number, String> {
@@ -29,7 +29,7 @@ pub fn sqrt(input: d128) -> d128 {
   let mut n = d128!(1);
   let half = d128!(0.5);
   for _ in 0..10 {
-    n = (n + input/n) * half;
+    n = (n + input / n) * half;
   }
   n
 }
@@ -40,8 +40,8 @@ pub fn cbrt(input: d128) -> d128 {
   // hope that 20 iterations makes it accurate enough
   let three = d128!(3);
   for _ in 0..20 {
-    let z2 = n*n;
+    let z2 = n * n;
-    n = n - ((n*z2 - input) / (three*z2));
+    n = n - ((n * z2 - input) / (three * z2));
   }
   n
 }
@@ -68,12 +68,11 @@ pub fn sin(mut input: d128) -> d128 {
   let mut result = d128!(0);
   for i_int in 0..precision {
     let i = d128::from(i_int);
-    let calc_result = two*i+one;
+    let calc_result = two * i + one;
     result += neg_one.pow(i) * (input.pow(calc_result) / factorial(calc_result));
   }
 
   negative_correction * result
-  
 }
 
 /// Returns the cosine of a [`struct@d128`]
@@ -92,18 +91,16 @@ fn evaluate_node(ast_node: &AstNode) -> Result<Number, String> {
   let token = &ast_node.token;
   let children = &ast_node.children;
   match token {
-    Token::Number(number) => {
+    Token::Number(number) => Ok(Number::new(*number, Unit::NoUnit)),
-      Ok(Number::new(*number, Unit::NoUnit))
+    Token::Constant(constant) => match constant {
-    },
+      Pi => Ok(Number::new(
-    Token::Constant(constant) => {
+        d128!(3.141592653589793238462643383279503),
-      match constant {
+        Unit::NoUnit,
-        Pi => {
+      )),
-          Ok(Number::new(d128!(3.141592653589793238462643383279503), Unit::NoUnit))
+      E => Ok(Number::new(
-        },
+        d128!(2.718281828459045235360287471352662),
-        E => {
+        Unit::NoUnit,
-          Ok(Number::new(d128!(2.718281828459045235360287471352662), Unit::NoUnit))
+      )),
-        },
-      }
     },
     Token::FunctionIdentifier(function) => {
       let child_node = children.get(0).ok_or("Paren has no child[0]")?;
@@ -116,7 +113,7 @@ fn evaluate_node(ast_node: &AstNode) -> Result<Number, String> {
           } else {
             Err("log() only accepts UnitType::NoType".to_string())
           }
-        },
+        }
         Sqrt => {
           if child_answer.unit.category() == UnitType::NoType {
             let result = sqrt(child_answer.value);
@@ -124,7 +121,7 @@ fn evaluate_node(ast_node: &AstNode) -> Result<Number, String> {
           } else {
             Err("log() only accepts UnitType::NoType".to_string())
           }
-        },
+        }
         Log => {
           if child_answer.unit.category() == UnitType::NoType {
             let result = child_answer.value.log10();
@@ -132,7 +129,7 @@ fn evaluate_node(ast_node: &AstNode) -> Result<Number, String> {
           } else {
             Err("log() only accepts UnitType::NoType".to_string())
           }
-        },
+        }
         Ln => {
           if child_answer.unit.category() == UnitType::NoType {
             let result = child_answer.value.ln();
@@ -140,7 +137,7 @@ fn evaluate_node(ast_node: &AstNode) -> Result<Number, String> {
           } else {
             Err("ln() only accepts UnitType::NoType".to_string())
           }
-        },
+        }
         Exp => {
           if child_answer.unit.category() == UnitType::NoType {
             let result = child_answer.value.exp(child_answer.value);
@@ -148,79 +145,92 @@ fn evaluate_node(ast_node: &AstNode) -> Result<Number, String> {
           } else {
             Err("exp() only accepts UnitType::NoType".to_string())
           }
-        },
+        }
         Round => {
           // .quantize() rounds .5 to nearest even integer, so we correct that
           let mut result = child_answer.value.quantize(d128!(1));
           let rounding_change = result - child_answer.value;
           // If the result was rounded down by 0.5, correct by +1
-          if rounding_change == d128!(-0.5) { result += d128!(1); }
+          if rounding_change == d128!(-0.5) {
+            result += d128!(1);
+          }
           Ok(Number::new(result, child_answer.unit))
-        },
+        }
         Ceil => {
           let mut result = child_answer.value.quantize(d128!(1));
           let rounding_change = result - child_answer.value;
-          if rounding_change.is_negative() { result += d128!(1); }
+          if rounding_change.is_negative() {
+            result += d128!(1);
+          }
           Ok(Number::new(result, child_answer.unit))
-        },
+        }
         Floor => {
           let mut result = child_answer.value.quantize(d128!(1));
           let rounding_change = result - child_answer.value;
-          if !rounding_change.is_negative() { result -= d128!(1); }
+          if !rounding_change.is_negative() {
+            result -= d128!(1);
+          }
           Ok(Number::new(result, child_answer.unit))
-        },
+        }
         Abs => {
           let mut result = child_answer.value.abs();
           let rounding_change = result - child_answer.value;
-          if rounding_change == d128!(-0.5) { result += d128!(1); }
+          if rounding_change == d128!(-0.5) {
+            result += d128!(1);
+          }
           Ok(Number::new(result, child_answer.unit))
-        },
+        }
         Sin => {
           let result = sin(child_answer.value);
           Ok(Number::new(result, child_answer.unit))
-        },
+        }
         Cos => {
           let result = cos(child_answer.value);
           Ok(Number::new(result, child_answer.unit))
-        },
+        }
         Tan => {
           let result = tan(child_answer.value);
           Ok(Number::new(result, child_answer.unit))
-        },
+        }
       }
     }
     Token::Unit(unit) => {
       let child_node = children.get(0).ok_or("Unit has no child[0]")?;
       let child_answer = evaluate_node(child_node)?;
       Ok(Number::new(child_answer.value, *unit))
-    },
+    }
     Token::Negative => {
       let child_node = children.get(0).ok_or("Negative has no child[0]")?;
       let child_answer = evaluate_node(child_node)?;
       Ok(Number::new(-child_answer.value, child_answer.unit))
-    },
+    }
     Token::Paren => {
       let child_node = children.get(0).ok_or("Paren has no child[0]")?;
       evaluate_node(child_node)
-    },
+    }
     Token::UnaryOperator(operator) => {
-      let child_node = children.get(0).ok_or(format!("Token {:?} has no child[0]", token))?;
+      let child_node = children
+        .get(0)
+        .ok_or(format!("Token {:?} has no child[0]", token))?;
       let child_answer = evaluate_node(child_node)?;
       match operator {
-        Percent => {
+        Percent => Ok(Number::new(
-          Ok(Number::new(child_answer.value / d128!(100), child_answer.unit))
+          child_answer.value / d128!(100),
-        },
+          child_answer.unit,
+        )),
         Factorial => {
           let result = factorial(child_answer.value);
           if result.is_nan() {
             return Err("Can only perform factorial on integers from 0 to 1000".to_string());
           }
           Ok(Number::new(result, child_answer.unit))
-        },
+        }
       }
-    },
+    }
     Token::NamedNumber(named_number) => {
-      let child_node = children.get(0).ok_or(format!("Token {:?} has no child[0]", token))?;
+      let child_node = children
+        .get(0)
+        .ok_or(format!("Token {:?} has no child[0]", token))?;
       let named_number_value = lookup_named_number(named_number);
       if let Token::NamedNumber(child_nn) = &child_node.token {
         let child_nn_value = lookup_named_number(child_nn);
@@ -233,8 +243,12 @@ fn evaluate_node(ast_node: &AstNode) -> Result<Number, String> {
       Ok(Number::new(result, child_answer.unit))
     }
     Token::TextOperator(operator) => {
-      let left_child = children.get(0).ok_or(format!("Token {:?} has no child[0]", token))?;
+      let left_child = children
-      let right_child = children.get(1).ok_or(format!("Token {:?} has no child[1]", token))?;
+        .get(0)
+        .ok_or(format!("Token {:?} has no child[0]", token))?;
+      let right_child = children
+        .get(1)
+        .ok_or(format!("Token {:?} has no child[1]", token))?;
 
       match operator {
         To => {
@@ -245,7 +259,7 @@ fn evaluate_node(ast_node: &AstNode) -> Result<Number, String> {
           } else {
             Err("Right side of To operator needs to be a unit".to_string())
           }
-        },
+        }
         Of => {
           let left = evaluate_node(left_child)?;
           let right = evaluate_node(right_child)?;
@@ -254,44 +268,40 @@ fn evaluate_node(ast_node: &AstNode) -> Result<Number, String> {
           } else {
             Err("Left side of the Of operator must be NoUnit".to_string())
           }
-        },
+        }
       }
-    },
+    }
     Token::Operator(operator) => {
-      let left_child = children.get(0).ok_or(format!("Token {:?} has no child[0]", token))?;
+      let left_child = children
-      let right_child = children.get(1).ok_or(format!("Token {:?} has no child[1]", token))?;
+        .get(0)
+        .ok_or(format!("Token {:?} has no child[0]", token))?;
+      let right_child = children
+        .get(1)
+        .ok_or(format!("Token {:?} has no child[1]", token))?;
       let left = evaluate_node(left_child)?;
       let right = evaluate_node(right_child)?;
       match operator {
-        Plus => {
+        Plus => Ok(add(left, right)?),
-          Ok(add(left, right)?)
+        Minus => Ok(subtract(left, right)?),
-        },
-        Minus => {
-          Ok(subtract(left, right)?)
-        },
         Multiply => {
           Ok(multiply(left, right)?)
           // }
-        },
+        }
         Divide => {
           Ok(divide(left, right)?)
           // }
-        },
+        }
         Modulo => {
           Ok(modulo(left, right)?)
           // }
-        },
+        }
         Caret => {
           Ok(pow(left, right)?)
           // }
-        },
-        _ => {
-          Err(format!("Unexpected operator {:?}", operator))
         }
+        _ => Err(format!("Unexpected operator {:?}", operator)),
       }
-    },
-    _ => {
-      Err(format!("Unexpected token {:?}", token))
     }
+    _ => Err(format!("Unexpected token {:?}", token)),
   }
 }

src/lib.rs

@@ -1,9 +1,9 @@
 #![cfg_attr(
   feature = "cargo-clippy",
   allow(
-      clippy::comparison_chain,
+    clippy::comparison_chain,
-      clippy::if_same_then_else,
+    clippy::if_same_then_else,
-      clippy::match_like_matches_macro,
+    clippy::match_like_matches_macro,
   )
 )]
 //! calculation + conversion
@@ -30,20 +30,23 @@
 //! }
 //! ```
 
+use crate::units::Unit;
+use decimal::d128;
 use std::fmt::{self, Display};
 use std::time::Instant;
-use decimal::d128;
-use crate::units::Unit;
 
-/// Units, and functions you can use with them
-pub mod units;
-/// Turns a string into [`Token`]s
-pub mod lexer;
-/// Turns [`Token`]s into an [`AstNode`](parser::AstNode)
-pub mod parser;
 /// Turns an [`AstNode`](parser::AstNode) into a [`Number`]
 pub mod evaluator;
+/// Turns a string into [`Token`]s
+#[rustfmt::skip]
+pub mod lexer;
+#[rustfmt::skip]
 mod lookup;
+/// Turns [`Token`]s into an [`AstNode`](parser::AstNode)
+pub mod parser;
+/// Units, and functions you can use with them
+#[rustfmt::skip]
+pub mod units;
 
 #[derive(Clone, Debug)]
 /// A number with a `Unit`.
@@ -92,7 +95,7 @@ pub enum Operator {
   Divide,
   Modulo,
   Caret,
-  LeftParen, // lexer only
+  LeftParen,  // lexer only
   RightParen, // lexer only
 }
 
@@ -213,7 +216,7 @@ pub enum Token {
 macro_rules! numtok {
   ( $num:literal ) => {
     Token::Number(d128!($num))
-  }
+  };
 }
 
 /// Evaluates a string into a resulting [`Number`].
@@ -233,20 +236,28 @@ macro_rules! numtok {
 ///     }
 /// }
 /// ```
-pub fn eval(input: &str, allow_trailing_operators: bool, default_degree: Unit, verbose: bool) -> Result<Number, String> {
+pub fn eval(
-
+  input: &str,
+  allow_trailing_operators: bool,
+  default_degree: Unit,
+  verbose: bool,
+) -> Result<Number, String> {
   let lex_start = Instant::now();
 
   match lexer::lex(input, allow_trailing_operators, default_degree) {
     Ok(tokens) => {
       let lex_time = Instant::now().duration_since(lex_start).as_nanos() as f32;
-      if verbose { println!("Lexed TokenVector: {:?}", tokens); }
+      if verbose {
+        println!("Lexed TokenVector: {:?}", tokens);
+      }
 
       let parse_start = Instant::now();
       match parser::parse(&tokens) {
         Ok(ast) => {
           let parse_time = Instant::now().duration_since(parse_start).as_nanos() as f32;
-          if verbose { println!("Parsed AstNode: {:#?}", ast); }
+          if verbose {
+            println!("Parsed AstNode: {:#?}", ast);
+          }
 
           let eval_start = Instant::now();
           match evaluator::evaluate(&ast) {
@@ -255,19 +266,19 @@ pub fn eval(input: &str, allow_trailing_operators: bool, default_degree: Unit, v
 
               if verbose {
                 println!("Evaluated value: {} {:?}", answer.value, answer.unit);
-                println!("\u{23f1}  {:.3}ms lexing", lex_time/1000.0/1000.0);
+                println!("\u{23f1}  {:.3}ms lexing", lex_time / 1000.0 / 1000.0);
-                println!("\u{23f1}  {:.3}ms parsing", parse_time/1000.0/1000.0);
+                println!("\u{23f1}  {:.3}ms parsing", parse_time / 1000.0 / 1000.0);
-                println!("\u{23f1}  {:.3}ms evaluation", eval_time/1000.0/1000.0);
+                println!("\u{23f1}  {:.3}ms evaluation", eval_time / 1000.0 / 1000.0);
               }
 
               Ok(answer)
-            },
+            }
             Err(e) => Err(format!("Eval error: {}", e)),
           }
-        },
+        }
         Err(e) => Err(format!("Parsing error: {}", e)),
       }
-    },
+    }
     Err(e) => Err(format!("Lexing error: {}", e)),
   }
 }

src/main.rs

@@ -1,7 +1,7 @@
 use cpc::eval;
 use cpc::units::Unit;
-use std::process::exit;
 use std::env;
+use std::process::exit;
 
 const VERSION: &str = env!("CARGO_PKG_VERSION");
 
@@ -30,12 +30,12 @@ fn main() {
       "--version" => {
         println!("{}", VERSION);
         exit(0);
-      },
+      }
       "--help" => {
         print_help();
         exit(0);
-      },
+      }
-      _ => {},
+      _ => {}
     }
   }
   let mut verbose = false;
@@ -58,7 +58,7 @@ fn main() {
     None => {
       print_help();
       exit(0);
-    },
+    }
   };
 
   match eval(&expression, true, Unit::Celsius, verbose) {
@@ -66,10 +66,10 @@ fn main() {
       if !verbose {
         println!("{}", answer);
       }
-    },
+    }
     Err(e) => {
       eprintln!("{}", e);
       exit(1);
-    },
+    }
   }
 }

src/parser.rs

@@ -1,8 +1,8 @@
-use crate::Token;
-use crate::Operator::{Caret, Divide, LeftParen, Minus, Modulo, Multiply, Plus, RightParen};
-use crate::UnaryOperator::{Percent, Factorial};
-use crate::TextOperator::{To, Of};
 use crate::units::Unit::{Foot, Inch};
+use crate::Operator::{Caret, Divide, LeftParen, Minus, Modulo, Multiply, Plus, RightParen};
+use crate::TextOperator::{Of, To};
+use crate::Token;
+use crate::UnaryOperator::{Factorial, Percent};
 
 #[derive(Debug)]
 /// A struct with a [`Token`](AstNode::token) and [`AstNode`] [`children`](AstNode::children)
@@ -24,10 +24,15 @@ impl AstNode {
 
 /// Parse [`Token`]s into an Abstract Syntax Tree ([`AstNode`])
 pub fn parse(tokens: &[Token]) -> Result<AstNode, String> {
-  parse_level_1(tokens, 0).and_then(|(ast, next_pos)| if next_pos == tokens.len() {
+  parse_level_1(tokens, 0).and_then(|(ast, next_pos)| {
+    if next_pos == tokens.len() {
       Ok(ast)
-  } else {
+    } else {
-      Err(format!("Expected end of input, found {:?} at {}", tokens[next_pos], next_pos))
+      Err(format!(
+        "Expected end of input, found {:?} at {}",
+        tokens[next_pos], next_pos
+      ))
+    }
   })
 }
 
@@ -49,12 +54,12 @@ pub fn parse_level_1(tokens: &[Token], pos: usize) -> Result<(AstNode, usize), S
         new_node.children.push(right_node);
         node = new_node;
         pos = next_pos;
-      },
+      }
       // if there's no match, we go down to a lower precedence (or, in this
       // case, we're done)
       _ => {
         return Ok((node, pos));
-      },
+      }
     }
   }
 }
@@ -73,10 +78,10 @@ pub fn parse_level_2(tokens: &[Token], pos: usize) -> Result<(AstNode, usize), S
         new_node.children.push(right_node);
         node = new_node;
         pos = next_pos;
-      },
+      }
       _ => {
         return Ok((node, pos));
-      },
+      }
     }
   }
 }
@@ -96,21 +101,17 @@ pub fn parse_level_3(tokens: &[Token], pos: usize) -> Result<(AstNode, usize), S
           let new_node = AstNode {
             children: vec![
               AstNode {
-                children: vec![
+                children: vec![AstNode::new(token0.unwrap().clone())],
-                  AstNode::new(token0.unwrap().clone()),
-                ],
                 token: Token::Unit(Foot),
               },
               AstNode {
-                children: vec![
+                children: vec![AstNode::new(token2.unwrap().clone())],
-                  AstNode::new(token2.unwrap().clone()),
-                ],
                 token: Token::Unit(Inch),
               },
             ],
             token: Token::Operator(Plus),
           };
-          return Ok((new_node, pos + 4))
+          return Ok((new_node, pos + 4));
         }
       }
     }
@@ -121,14 +122,16 @@ pub fn parse_level_3(tokens: &[Token], pos: usize) -> Result<(AstNode, usize), S
   loop {
     let token = tokens.get(pos);
     match token {
-      Some(&Token::Operator(Multiply)) | Some(&Token::Operator(Divide)) | Some(&Token::Operator(Modulo)) => {
+      Some(&Token::Operator(Multiply))
+      | Some(&Token::Operator(Divide))
+      | Some(&Token::Operator(Modulo)) => {
         let (right_node, next_pos) = parse_level_4(tokens, pos + 1)?;
         let mut new_node = AstNode::new(token.unwrap().clone());
         new_node.children.push(node);
         new_node.children.push(right_node);
         node = new_node;
         pos = next_pos;
-      },
+      }
 
       // Below is implicative multiplication, for example '2pi'. Constants and
       // such will only end up here if they were unable to be parsed as part of
@@ -148,12 +151,12 @@ pub fn parse_level_3(tokens: &[Token], pos: usize) -> Result<(AstNode, usize), S
             new_node.children.push(right_node);
             node = new_node;
             pos = next_pos;
-          },
+          }
           _ => {
             return Ok((node, pos));
-          },
+          }
         }
-      },
+      }
       // 2pi, )pi
       Some(&Token::Constant(_)) => {
         let last_token = tokens.get(pos - 1);
@@ -165,12 +168,12 @@ pub fn parse_level_3(tokens: &[Token], pos: usize) -> Result<(AstNode, usize), S
             new_node.children.push(right_node);
             node = new_node;
             pos = next_pos;
-          },
+          }
           _ => {
             return Ok((node, pos));
-          },
+          }
         }
-      },
+      }
       // 2log(1), )log(1)
       Some(&Token::FunctionIdentifier(_)) => {
         let last_token = tokens.get(pos - 1);
@@ -182,32 +185,34 @@ pub fn parse_level_3(tokens: &[Token], pos: usize) -> Result<(AstNode, usize), S
             new_node.children.push(right_node);
             node = new_node;
             pos = next_pos;
-          },
+          }
           _ => {
             return Ok((node, pos));
-          },
+          }
         }
-      },
+      }
       // 2(3), pi(3), )(3)
       Some(&Token::Operator(LeftParen)) => {
         let last_token = tokens.get(pos - 1);
         match last_token {
-          Some(&Token::Number(_)) | Some(&Token::Constant(_)) | Some(&Token::Operator(RightParen)) => {
+          Some(&Token::Number(_))
+          | Some(&Token::Constant(_))
+          | Some(&Token::Operator(RightParen)) => {
             let (right_node, next_pos) = parse_level_4(tokens, pos)?;
             let mut new_node = AstNode::new(Token::Operator(Multiply));
             new_node.children.push(node);
             new_node.children.push(right_node);
             node = new_node;
             pos = next_pos;
-          },
+          }
           _ => {
             return Ok((node, pos));
-          },
+          }
         }
-      },
+      }
       _ => {
         return Ok((node, pos));
-      },
+      }
     }
   }
 }
@@ -226,10 +231,10 @@ pub fn parse_level_4(tokens: &[Token], pos: usize) -> Result<(AstNode, usize), S
         new_node.children.push(right_node);
         node = new_node;
         pos = next_pos;
-      },
+      }
       _ => {
         return Ok((node, pos));
-      },
+      }
     }
   }
 }
@@ -254,8 +259,8 @@ pub fn parse_level_5(tokens: &[Token], pos: usize) -> Result<(AstNode, usize), S
       let mut new_node = AstNode::new(Token::Negative);
       new_node.children.push(right_node);
       Ok((new_node, next_pos))
-    },
+    }
-    _ => parse_level_6(tokens, pos)
+    _ => parse_level_6(tokens, pos),
   }
 }
 
@@ -266,7 +271,9 @@ pub fn parse_level_6(tokens: &[Token], pos: usize) -> Result<(AstNode, usize), S
   loop {
     let token = tokens.get(pos);
     match token {
-      Some(&Token::UnaryOperator(Factorial)) | Some(&Token::UnaryOperator(Percent)) | Some(&Token::NamedNumber(_)) => {
+      Some(&Token::UnaryOperator(Factorial))
+      | Some(&Token::UnaryOperator(Percent))
+      | Some(&Token::NamedNumber(_)) => {
         // Here we are handling unary operators, aka stuff written as
         // "Number Operator" (3!) instead of "Number Operator Number" (3+3).
         // Therefore, if we find a match, we don't parse what comes after it.
@@ -274,19 +281,19 @@ pub fn parse_level_6(tokens: &[Token], pos: usize) -> Result<(AstNode, usize), S
         new_node.children.push(node);
         node = new_node;
         pos += 1;
-      },
+      }
       Some(&Token::Unit(_unit)) => {
         // We won't allow units to repeat, like "1min min", so we end the loop if it's found.
         let mut new_node = AstNode::new(token.unwrap().clone());
         new_node.children.push(node);
         return Ok((new_node, pos + 1));
-      },
+      }
       _ => {
         // let's say we parse 1+2. parse_level_7 then returns 1, and token
         // is set to plus. Plus has lower precedence than level 4, so we
         // don't do anything, and pass the number down to a lower precedence.
         return Ok((node, pos));
-      },
+      }
     }
   }
 }
@@ -298,20 +305,22 @@ pub fn parse_level_6(tokens: &[Token], pos: usize) -> Result<(AstNode, usize), S
 /// [`FunctionIdentifier`](Token::FunctionIdentifier),
 /// [`Paren`](Token::Paren)
 pub fn parse_level_7(tokens: &[Token], pos: usize) -> Result<(AstNode, usize), String> {
-  let token: &Token = tokens.get(pos).ok_or(format!("Unexpected end of input at {}", pos))?;
+  let token: &Token = tokens
+    .get(pos)
+    .ok_or(format!("Unexpected end of input at {}", pos))?;
   match token {
     &Token::Number(_number) => {
       let node = AstNode::new(token.clone());
       Ok((node, pos + 1))
-    },
+    }
     &Token::Unit(_unit) => {
       let node = AstNode::new(token.clone());
       Ok((node, pos + 1))
-    },
+    }
     Token::Constant(_constant) => {
       let node = AstNode::new(token.clone());
       Ok((node, pos + 1))
-    },
+    }
     Token::FunctionIdentifier(_function_identifier) => {
       let left_paren_pos = pos + 1;
       let left_paren_token = tokens.get(left_paren_pos);
@@ -326,28 +335,36 @@ pub fn parse_level_7(tokens: &[Token], pos: usize) -> Result<(AstNode, usize), S
               function_node.children.push(node);
               Ok((function_node, next_pos + 1))
             } else {
-              Err(format!("Expected closing paren at {} but found {:?}", next_pos, tokens.get(next_pos)))
+              Err(format!(
+                "Expected closing paren at {} but found {:?}",
+                next_pos,
+                tokens.get(next_pos)
+              ))
             }
           })
-        },
-        _ => {
-          Err(format!("Expected ( after {} at {:?} but found {:?}", left_paren_pos, token, left_paren_token))
         }
+        _ => Err(format!(
+          "Expected ( after {} at {:?} but found {:?}",
+          left_paren_pos, token, left_paren_token
+        )),
       }
-    },
+    }
-    Token::Operator(LeftParen) => {
+    Token::Operator(LeftParen) => parse_level_1(tokens, pos + 1).and_then(|(node, next_pos)| {
-      parse_level_1(tokens, pos + 1).and_then(|(node, next_pos)| {
+      if let Some(&Token::Operator(RightParen)) = tokens.get(next_pos) {
-        if let Some(&Token::Operator(RightParen)) = tokens.get(next_pos) {
+        let mut paren_node = AstNode::new(Token::Paren);
-          let mut paren_node = AstNode::new(Token::Paren);
+        paren_node.children.push(node);
-          paren_node.children.push(node);
+        Ok((paren_node, next_pos + 1))
-          Ok((paren_node, next_pos + 1))
+      } else {
-        } else {
+        Err(format!(
-          Err(format!("Expected closing paren at {} but found {:?}", next_pos, tokens.get(next_pos)))
+          "Expected closing paren at {} but found {:?}",
-        }
+          next_pos,
-      })
+          tokens.get(next_pos)
-    },
+        ))
-    _ => {
+      }
-      Err(format!("Unexpected token {:?}, expected paren or number", token))
+    }),
-    },
+    _ => Err(format!(
+      "Unexpected token {:?}, expected paren or number",
+      token
+    )),
   }
 }