From febd5366e855ccb8dd06998737615e4f4e7d0717 Mon Sep 17 00:00:00 2001
From: Kasper <kasperkh.kh@gmail.com>
Date: Wed, 15 Jan 2020 17:45:53 +0100
Subject: [PATCH] Turned panics into errors

---
 src/evaluator.rs | 18 +++++++++---------
 src/lexer.rs     | 11 ++---------
 src/parser.rs    |  2 +-
 3 files changed, 12 insertions(+), 19 deletions(-)

diff --git a/src/evaluator.rs b/src/evaluator.rs
index 60d4f31..d14e919 100644
--- a/src/evaluator.rs
+++ b/src/evaluator.rs
@@ -94,7 +94,7 @@ fn evaluate_node(ast_node: &AstNode) -> Result<Number, String> {
       }
     },
     Token::FunctionIdentifier(function) => {
-      let child_node = children.get(0).expect("Paren has no child[0]");
+      let child_node = children.get(0).ok_or("Paren has no child[0]")?;
       let child_answer = evaluate_node(child_node)?;
       match function {
         Cbrt => {
@@ -178,21 +178,21 @@ fn evaluate_node(ast_node: &AstNode) -> Result<Number, String> {
       }
     }
     Token::Unit(unit) => {
-      let child_node = children.get(0).expect("Unit has no child[0]");
+      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.clone()))
     },
     Token::Negative => {
-      let child_node = children.get(0).expect("Negative has no child[0]");
+      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).expect("Paren has no child[0]");
+      let child_node = children.get(0).ok_or("Paren has no child[0]")?;
       return evaluate_node(child_node)
     },
     Token::UnaryOperator(operator) => {
-      let child_node = children.get(0).expect(format!("Token {:?} has no child[0]", token).as_str());
+      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 => {
@@ -208,8 +208,8 @@ fn evaluate_node(ast_node: &AstNode) -> Result<Number, String> {
       }
     },
     Token::TextOperator(operator) => {
-      let left_child = children.get(0).expect(format!("Token {:?} has no child[0]", token).as_str());
-      let right_child = children.get(1).expect(format!("Token {:?} has no child[1]", token).as_str());
+      let left_child = children.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 => {
@@ -233,8 +233,8 @@ fn evaluate_node(ast_node: &AstNode) -> Result<Number, String> {
       }
     },
     Token::Operator(operator) => {
-      let left_child = children.get(0).expect(format!("Token {:?} has no child[0]", token).as_str());
-      let right_child = children.get(1).expect(format!("Token {:?} has no child[1]", token).as_str());
+      let left_child = children.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 {
diff --git a/src/lexer.rs b/src/lexer.rs
index 1288d4b..8fca2ef 100644
--- a/src/lexer.rs
+++ b/src/lexer.rs
@@ -90,15 +90,8 @@ pub fn lex(input: &str, allow_trailing_operators: bool, default_degree: Unit) ->
           Some('2') | Some('3') => {
             byte_index += '2'.len_utf8();
             chars.next();
-            // match chars.peek().unwrap_or(&'-') {
-              // ...and if the 2 or 3 isn't part of a different number
-              // '.' | '0'..='9' => {
-              //   is_multidimensional = false;
-              // },
-              // we allow everything else and let the parser throw errors
-              // for things like km2pi
-              // _ => {}
-            // }
+            // we dont validate what comes after because it will be caught
+            // by the parser anyway (for example 3m35)
           },
           _ => is_multidimensional = false,
         }
diff --git a/src/parser.rs b/src/parser.rs
index 3cad1be..79114ab 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -267,7 +267,7 @@ fn parse_level_6(tokens: &TokenVector, pos: usize) -> Result<(AstNode, usize), S
 
 // level 7 precedence: numbers, parens
 fn parse_level_7(tokens: &TokenVector, pos: usize) -> Result<(AstNode, usize), String> {
-  let token: &Token = tokens.get(pos).expect(&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());