From 6c38d9b13b8e1cc976f9b22d15d100fd03ee54d4 Mon Sep 17 00:00:00 2001
From: Ivan Tham <pickfire@riseup.net>
Date: Sat, 3 Aug 2019 13:49:17 +0800
Subject: Reuse ans output and fix tests

---
 src/lex/mod.rs      |  4 ++--
 src/main.rs         | 24 +++++++++++++-----------
 src/readline/mod.rs |  2 +-
 3 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/src/lex/mod.rs b/src/lex/mod.rs
index cac16ca..caafd4b 100644
--- a/src/lex/mod.rs
+++ b/src/lex/mod.rs
@@ -122,7 +122,7 @@ fn factorial (n: f64) -> f64 {
         n.signum() * (1.. n.abs() as u64 +1).fold(1, |p, n| p*n) as f64
 }
 
-pub fn lexer(input: &str, prev_ans: &mut f64) -> Result<Vec<Token>, CalcError> {
+pub fn lexer(input: &str, prev_ans: f64) -> Result<Vec<Token>, CalcError> {
     let functions: HashMap<&str, Token> = get_functions();
     let operators: HashMap<char, Token> = get_operators();
 
@@ -159,7 +159,7 @@ pub fn lexer(input: &str, prev_ans: &mut f64) -> Result<Vec<Token>, CalcError> {
                     num_vec.clear();
                 }
                 last_char_is_op = false; 
-                result.push(Token::Num(*prev_ans));
+                result.push(Token::Num(prev_ans));
             }
             'a'...'z' | 'A'...'Z' => {
                 let parse_num = num_vec.parse::<f64>().ok();
diff --git a/src/main.rs b/src/main.rs
index 0742ee8..99d2059 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -43,7 +43,7 @@ lazy_static! {
 fn main() {
     if CONFIGURATION.input.len() > 0 {
         // command mode //
-        let evaled = eval_math_expression(&CONFIGURATION.input[..], &mut 0f64);
+        let evaled = eval_math_expression(&CONFIGURATION.input[..], 0f64);
         match evaled {
             Ok(ans) => pprint(ans),
             Err(e) => {
@@ -78,9 +78,12 @@ fn main() {
             match readline {
                 Ok(line) => {
                     rl.add_history_entry(line.as_str());
-                    let evaled = eval_math_expression(&line[..], &mut prev_ans);
+                    let evaled = eval_math_expression(&line[..], prev_ans);
                     match evaled {
-                        Ok(ans) => pprint(ans),
+                        Ok(ans) => {
+                            prev_ans = ans;
+                            pprint(ans);
+                        }
                         Err(e) => println!("{}", handler(e)),
                     };
                 },
@@ -145,7 +148,7 @@ fn parse_arguments() -> Configuration {
     }
 }
 
-pub fn eval_math_expression(input: &str, prev_ans: &mut f64) -> Result<f64, CalcError> {
+pub fn eval_math_expression(input: &str, prev_ans: f64) -> Result<f64, CalcError> {
     let input = input.trim();
     let input = input.replace(" ", "");
     if input.len() == 0 {
@@ -155,7 +158,6 @@ pub fn eval_math_expression(input: &str, prev_ans: &mut f64) -> Result<f64, Calc
     let lexed        = lexer(&input[..], prev_ans)?;
     let postfixed    = to_postfix(lexed)?;
     let evaled       = eval_postfix(postfixed)?;
-    *prev_ans         = evaled;
     let evaled_fixed = format!("{:.*}", CONFIGURATION.fix, evaled).parse::<f64>().unwrap();
     Ok(evaled_fixed)
 }
@@ -166,32 +168,32 @@ mod tests {
 
     #[test]
     fn basic_ops() {
-        let evaled = eval_math_expression("6*2 + 3 + 12 -3", &0f64).unwrap();
+        let evaled = eval_math_expression("6*2 + 3 + 12 -3", 0f64).unwrap();
         assert_eq!(24., evaled);
     }
     #[test]
     fn trignometric_fns() {
-        let evaled = eval_math_expression("sin(30) + tan(45", &0f64).unwrap();
+        let evaled = eval_math_expression("sin(30) + tan(45", 0f64).unwrap();
         assert_eq!(1.5, evaled);
     }
     #[test]
     fn brackets() {
-        let evaled = eval_math_expression("(((1 + 2 + 3) ^ 2 ) - 4)", &0f64).unwrap();
+        let evaled = eval_math_expression("(((1 + 2 + 3) ^ 2 ) - 4)", 0f64).unwrap();
         assert_eq!(32., evaled);
     }
     #[test]
     fn floating_ops() {
-        let evaled = eval_math_expression("1.2816 + 1 + 1.2816/1.2", &0f64).unwrap();
+        let evaled = eval_math_expression("1.2816 + 1 + 1.2816/1.2", 0f64).unwrap();
         assert_eq!(3.3496, evaled);
     }
     #[test]
     fn inverse_trignometric_fns() {
-        let evaled = eval_math_expression("deg(asin(1) + acos(1))", &0f64).unwrap();
+        let evaled = eval_math_expression("deg(asin(1) + acos(1))", 0f64).unwrap();
         assert_eq!(90., evaled);
     }
     #[test]
     fn prev_ans() {
-        let evaled = eval_math_expression("_ + 9", &9f64).unwrap();
+        let evaled = eval_math_expression("_ + 9", 9f64).unwrap();
         assert_eq!(18.0, evaled);
     }
 }
diff --git a/src/readline/mod.rs b/src/readline/mod.rs
index 9ae14ba..97f03bd 100644
--- a/src/readline/mod.rs
+++ b/src/readline/mod.rs
@@ -23,7 +23,7 @@ impl Highlighter for LineHighlighter {
         Owned(format!("\x1b[90m{}\x1b[0m", hint))
     }
     fn highlight<'l>(&self, line: &'l str, _: usize) -> Cow<'l, str> {
-        let op = eval_math_expression(line, &mut 0f64);
+        let op = eval_math_expression(line, 0f64);
         match op {
             Ok(_) => {
                 let functions = [
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