From 26992c9e32b25b7881acb20c677578da0e52d37a Mon Sep 17 00:00:00 2001
From: Kasper <kasperkh.kh@gmail.com>
Date: Sat, 28 Dec 2019 06:31:50 +0100
Subject: [PATCH] Evaluation of sin, cos, tan

---
 src/evaluator.rs | 72 ++++++++++++++++++++++++++++++++++--------------
 src/lexer.rs     | 11 +-------
 src/main.rs      |  9 ------
 3 files changed, 52 insertions(+), 40 deletions(-)

diff --git a/src/evaluator.rs b/src/evaluator.rs
index 1735d18..f7c87e6 100644
--- a/src/evaluator.rs
+++ b/src/evaluator.rs
@@ -10,8 +10,8 @@ use crate::FunctionIdentifier::*;
 
 #[derive(Clone, Debug)]
 pub struct Answer {
-  value: d128,
-  unit: Unit,
+  pub value: d128,
+  pub unit: Unit,
 }
 
 impl Answer {
@@ -56,6 +56,44 @@ fn cbrt(input: d128) -> d128 {
   return n
 }
 
+fn sin(mut input: d128) -> d128 {
+  let pi = d128!(3.141592653589793238462643383279503);
+  let pi2 = d128!(6.283185307179586476925286766559006);
+
+  input %= pi2;
+
+  let negative_correction = if input.is_negative() {
+    input -= pi;
+    d128!(-1)
+  } else {
+    d128!(1)
+  };
+
+  let one = d128!(1);
+  let two = d128!(2);
+  let neg_one = -one;
+
+  let precision = 37;
+  let mut result = d128!(0);
+  for i_int in 0..precision {
+    let i = d128::from(i_int);
+    let calc_result = two*i+one;
+    result += neg_one.pow(i) * (input.pow(calc_result) / factorial(calc_result, one, two));
+  }
+
+  return negative_correction * result;
+  
+}
+
+fn cos(input: d128) -> d128 {
+  let half_pi = d128!(1.570796326794896619231321691639751);
+  return sin(half_pi - input);
+}
+
+fn tan(input: d128) -> d128 {
+  return sin(input) / cos(input);
+}
+
 fn evaluate_node(ast_node: &AstNode) -> Result<Answer, String> {
   let token = &ast_node.token;
   let children = &ast_node.children;
@@ -143,25 +181,17 @@ fn evaluate_node(ast_node: &AstNode) -> Result<Answer, String> {
           if rounding_change == d128!(-0.5) { result += d128!(1); }
           return Ok(Answer::new(result, child_answer.unit))
         },
-
-        // Sin,
-        // Cos,
-        // Tan,
-        // Asin,
-        // Acos,
-        // Atan,
-        // Sinh,
-        // Cosh,
-        // Tanh,
-        // Asinh,
-        // Acosh,
-        // Atanh,
-        // Sin
-        // Sinh
-        // Tan
-        // Tanh
-        _ => {
-          return Err(format!("EVAL UNSUPPORTED FUNC").to_string())
+        Sin => {
+          let result = sin(child_answer.value);
+          return Ok(Answer::new(result, child_answer.unit))
+        },
+        Cos => {
+          let result = cos(child_answer.value);
+          return Ok(Answer::new(result, child_answer.unit))
+        },
+        Tan => {
+          let result = tan(child_answer.value);
+          return Ok(Answer::new(result, child_answer.unit))
         },
       }
     }
diff --git a/src/lexer.rs b/src/lexer.rs
index 8fece60..91aa075 100644
--- a/src/lexer.rs
+++ b/src/lexer.rs
@@ -5,7 +5,7 @@ use crate::Operator::{Caret, Divide, LeftParen, Minus, Modulo, Multiply, Plus, R
 use crate::UnaryOperator::{Percent, Factorial};
 use crate::TextOperator::{Of, To};
 use crate::Constant::{E, Pi};
-use crate::FunctionIdentifier::{Acos, Acosh, Asin, Asinh, Atan, Atanh, Cbrt, Ceil, Cos, Cosh, Exp, Abs, Floor, Ln, Log, Round, Sin, Sinh, Sqrt, Tan, Tanh};
+use crate::FunctionIdentifier::{Cbrt, Ceil, Cos, Exp, Abs, Floor, Ln, Log, Round, Sin, Sqrt, Tan};
 use crate::units::Unit::*;
 
 pub fn lex(input: &str) -> Result<TokenVector, String> {
@@ -84,15 +84,6 @@ pub fn lex(input: &str) -> Result<TokenVector, String> {
           "sin" => tokens.push(Token::FunctionIdentifier(Sin)),
           "cos" => tokens.push(Token::FunctionIdentifier(Cos)),
           "tan" => tokens.push(Token::FunctionIdentifier(Tan)),
-          "asin" => tokens.push(Token::FunctionIdentifier(Asin)),
-          "acos" => tokens.push(Token::FunctionIdentifier(Acos)),
-          "atan" => tokens.push(Token::FunctionIdentifier(Atan)),
-          "sinh" => tokens.push(Token::FunctionIdentifier(Sinh)),
-          "cosh" => tokens.push(Token::FunctionIdentifier(Cosh)),
-          "tanh" => tokens.push(Token::FunctionIdentifier(Tanh)),
-          "asinh" => tokens.push(Token::FunctionIdentifier(Asinh)),
-          "acosh" => tokens.push(Token::FunctionIdentifier(Acosh)),
-          "atanh" => tokens.push(Token::FunctionIdentifier(Atanh)),
 
           "ns" | "nanosecond" | "nanoseconds" => tokens.push(Token::Unit(Nanosecond)),
           "μs" | "us" | "microsecond" | "microseconds" => tokens.push(Token::Unit(Microsecond)),
diff --git a/src/main.rs b/src/main.rs
index 4076d76..4c97d5a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -50,15 +50,6 @@ pub enum FunctionIdentifier {
   Sin,
   Cos,
   Tan,
-  Asin,
-  Acos,
-  Atan,
-  Sinh,
-  Cosh,
-  Tanh,
-  Asinh,
-  Acosh,
-  Atanh,
 }
 
 mod units;