add sin cos tan to stdlib and make sure you cant redeclare a stdlib fn (#497)

more tests

Signed-off-by: Jess Frazelle <github@jessfraz.com>

src/wasm-lib/kcl/src/parser.rs

@@ -1287,7 +1287,8 @@ impl Parser {
         let current_token = self.get_token(index)?;
 
         // Make sure they are not assigning a variable to a reserved keyword.
-        if current_token.token_type == TokenType::Keyword {
+        // Or a stdlib function.
+        if current_token.token_type == TokenType::Keyword || self.stdlib.fns.contains_key(&current_token.value) {
             return Err(KclError::Syntax(KclErrorDetails {
                 source_ranges: vec![current_token.into()],
                 message: format!(
@@ -1399,7 +1400,8 @@ impl Parser {
         }
 
         // Make sure they are not assigning a variable to a reserved keyword.
-        if argument_token.token_type == TokenType::Keyword {
+        // Or a stdlib function.
+        if argument_token.token_type == TokenType::Keyword || self.stdlib.fns.contains_key(&argument_token.value) {
             return Err(KclError::Syntax(KclErrorDetails {
                 source_ranges: vec![argument_token.clone().into()],
                 message: format!(
@@ -3287,6 +3289,19 @@ e
         );
     }
 
+    #[test]
+    fn test_error_stdlib_in_fn_name() {
+        let some_program_string = r#"fn cos = () {}"#;
+        let tokens = crate::tokeniser::lexer(some_program_string);
+        let parser = crate::parser::Parser::new(tokens);
+        let result = parser.ast();
+        assert!(result.is_err());
+        assert_eq!(
+            result.err().unwrap().to_string(),
+            r#"syntax: KclErrorDetails { source_ranges: [SourceRange([3, 6])], message: "Cannot assign a variable to a reserved keyword: cos" }"#
+        );
+    }
+
     #[test]
     fn test_error_keyword_in_fn_args() {
         let some_program_string = r#"fn thing = (let) => {
@@ -3302,6 +3317,21 @@ e
         );
     }
 
+    #[test]
+    fn test_error_stdlib_in_fn_args() {
+        let some_program_string = r#"fn thing = (cos) => {
+    return 1
+}"#;
+        let tokens = crate::tokeniser::lexer(some_program_string);
+        let parser = crate::parser::Parser::new(tokens);
+        let result = parser.ast();
+        assert!(result.is_err());
+        assert_eq!(
+            result.err().unwrap().to_string(),
+            r#"syntax: KclErrorDetails { source_ranges: [SourceRange([12, 15])], message: "Cannot assign a variable to a reserved keyword: cos" }"#
+        );
+    }
+
     #[test]
     fn test_keyword_ok_in_fn_args_return() {
         let some_program_string = r#"fn thing = (param) => {

src/wasm-lib/kcl/src/std/math.rs

@@ -0,0 +1,70 @@
+//! Functions related to mathematics.
+
+use anyhow::Result;
+use derive_docs::stdlib;
+use schemars::JsonSchema;
+
+use crate::{errors::KclError, executor::MemoryItem, std::Args};
+
+/// Computes the cosine of a number (in radians).
+pub fn cos(args: &mut Args) -> Result<MemoryItem, KclError> {
+    let num = args.get_number()?;
+    let result = inner_cos(num)?;
+
+    args.make_user_val_from_f64(result)
+}
+
+/// Computes the sine of a number (in radians).
+#[stdlib {
+    name = "cos",
+}]
+fn inner_cos(num: f64) -> Result<f64, KclError> {
+    Ok(num.cos())
+}
+
+/// Computes the sine of a number (in radians).
+pub fn sin(args: &mut Args) -> Result<MemoryItem, KclError> {
+    let num = args.get_number()?;
+    let result = inner_sin(num)?;
+
+    args.make_user_val_from_f64(result)
+}
+
+/// Computes the sine of a number (in radians).
+#[stdlib {
+    name = "sin",
+}]
+fn inner_sin(num: f64) -> Result<f64, KclError> {
+    Ok(num.sin())
+}
+
+/// Computes the tangent of a number (in radians).
+pub fn tan(args: &mut Args) -> Result<MemoryItem, KclError> {
+    let num = args.get_number()?;
+    let result = inner_tan(num)?;
+
+    args.make_user_val_from_f64(result)
+}
+
+/// Computes the tangent of a number (in radians).
+#[stdlib {
+    name = "tan",
+}]
+fn inner_tan(num: f64) -> Result<f64, KclError> {
+    Ok(num.tan())
+}
+
+/// Return the value of `pi`.
+pub fn pi(args: &mut Args) -> Result<MemoryItem, KclError> {
+    let result = inner_pi()?;
+
+    args.make_user_val_from_f64(result)
+}
+
+/// Return the value of `pi`.
+#[stdlib {
+    name = "pi",
+}]
+fn inner_pi() -> Result<f64, KclError> {
+    Ok(std::f64::consts::PI)
+}

src/wasm-lib/kcl/src/std/mod.rs

@@ -1,6 +1,7 @@
 //! Functions implemented for language execution.
 
 pub mod extrude;
+pub mod math;
 pub mod segment;
 pub mod sketch;
 pub mod utils;
@@ -61,6 +62,10 @@ impl StdLib {
             Box::new(crate::std::sketch::Close),
             Box::new(crate::std::sketch::Arc),
             Box::new(crate::std::sketch::BezierCurve),
+            Box::new(crate::std::math::Cos),
+            Box::new(crate::std::math::Sin),
+            Box::new(crate::std::math::Tan),
+            Box::new(crate::std::math::Pi),
         ];
 
         let mut fns = HashMap::new();
@@ -122,6 +127,21 @@ impl<'a> Args<'a> {
         )?))
     }
 
+    fn get_number(&self) -> Result<f64, KclError> {
+        let first_value = self
+            .args
+            .first()
+            .ok_or_else(|| {
+                KclError::Type(KclErrorDetails {
+                    message: format!("Expected a number as the first argument, found `{:?}`", self.args),
+                    source_ranges: vec![self.source_range],
+                })
+            })?
+            .get_json_value()?;
+
+        parse_json_number_as_f64(&first_value, self.source_range)
+    }
+
     fn get_number_array(&self) -> Result<Vec<f64>, KclError> {
         let mut numbers: Vec<f64> = Vec::new();
         for arg in &self.args {