From 9d0b667deadf9e64d3b692274275d57a61c107c5 Mon Sep 17 00:00:00 2001
From: end-4 <97237370+end-4@users.noreply.github.com>
Date: Wed, 16 Aug 2023 18:40:24 +0700
Subject: [PATCH] Add trigonometric functions (#823)

---
 CHANGELOG.md                    |  1 +
 crates/simplexpr/src/eval.rs    | 42 +++++++++++++++++++++++++++++++++
 docs/src/expression_language.md |  3 +++
 3 files changed, 46 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8f3bbcb..7744ad6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ All notable changes to eww will be listed here, starting at changes since versio
 - Add `jq` function, offering jq-style json processing
 - Add `justify` property to the label widget, allowing text justification (By: n3oney)
 - Add `EWW_TIME` magic variable (By: Erenoit)
+- Add trigonometric functions (`sin`, `cos`, `tan`, `cot`) and degree/radian conversions (`degtorad`, `radtodeg`) (By: end-4)
 
 ## [0.4.0] (04.09.2022)
 
diff --git a/crates/simplexpr/src/eval.rs b/crates/simplexpr/src/eval.rs
index c0b029d..c890ce8 100644
--- a/crates/simplexpr/src/eval.rs
+++ b/crates/simplexpr/src/eval.rs
@@ -320,6 +320,48 @@ fn call_expr_function(name: &str, args: Vec<DynVal>) -> Result<DynVal, EvalError
             }
             _ => Err(EvalError::WrongArgCount(name.to_string())),
         },
+        "sin" => match args.as_slice() {
+            [num] => {
+                let num = num.as_f64()?;
+                Ok(DynVal::from(num.sin()))
+            }
+            _ => Err(EvalError::WrongArgCount(name.to_string())),
+        },
+        "cos" => match args.as_slice() {
+            [num] => {
+                let num = num.as_f64()?;
+                Ok(DynVal::from(num.cos()))
+            }
+            _ => Err(EvalError::WrongArgCount(name.to_string())),
+        },
+        "tan" => match args.as_slice() {
+            [num] => {
+                let num = num.as_f64()?;
+                Ok(DynVal::from(num.tan()))
+            }
+            _ => Err(EvalError::WrongArgCount(name.to_string())),
+        },
+        "cot" => match args.as_slice() {
+            [num] => {
+                let num = num.as_f64()?;
+                Ok(DynVal::from(1.0 / num.tan()))
+            }
+            _ => Err(EvalError::WrongArgCount(name.to_string())),
+        },
+        "degtorad" => match args.as_slice() {
+            [num] => {
+                let num = num.as_f64()?;
+                Ok(DynVal::from(num.to_radians()))
+            }
+            _ => Err(EvalError::WrongArgCount(name.to_string())),
+        },
+        "radtodeg" => match args.as_slice() {
+            [num] => {
+                let num = num.as_f64()?;
+                Ok(DynVal::from(num.to_degrees()))
+            }
+            _ => Err(EvalError::WrongArgCount(name.to_string())),
+        },
         "matches" => match args.as_slice() {
             [string, pattern] => {
                 let string = string.as_string()?;
diff --git a/docs/src/expression_language.md b/docs/src/expression_language.md
index 57e15ea..7d54811 100644
--- a/docs/src/expression_language.md
+++ b/docs/src/expression_language.md
@@ -39,6 +39,9 @@ Supported currently are the following features:
     - for this, the object/array value needs to refer to a variable that contains a valid json string.
 - some function calls:
     - `round(number, decimal_digits)`: Round a number to the given amount of decimals
+    - `sin(number)`, `cos(number)`, `tan(number)`, `cot(number)`: Calculate the trigonometric value of a given number in **radians**
+    - `degtorad(number)`: Converts a number from degrees to radians
+    - `radtodeg(number)`: Converts a number from radians to degrees
     - `replace(string, regex, replacement)`: Replace matches of a given regex in a string
 	- `search(string, regex)`: Search for a given regex in a string (returns array)
 	- `matches(string, regex)`: check if a given string matches a given regex (returns bool)