New math parser (#956)

* New math parser

* Remove old parser

* Comments

* Move tests into parser_impl, remove dead code

* Backport some math tests

src/lang/abstractSyntaxTree.test.ts

@@ -1443,7 +1443,7 @@ describe('nests binary expressions correctly', () => {
             type: 'BinaryExpression',
             operator: '*',
             start: 15,
-            end: 26,
+            end: 25,
             left: { type: 'Literal', value: 2, raw: '2', start: 15, end: 16 },
             right: {
               type: 'BinaryExpression',

src/wasm-lib/kcl/Cargo.toml

@@ -50,6 +50,9 @@ engine = []
 panic = "abort"
 debug = true
 
+[profile.bench]
+debug = true # Flamegraphs of benchmarks require accurate debug symbols
+
 [dev-dependencies]
 criterion = "0.5.1"
 expectorate = "1.1.0"

src/wasm-lib/kcl/src/ast/types.rs

@@ -2175,6 +2175,7 @@ impl BinaryExpression {
             BinaryOperator::Mul => (left * right).into(),
             BinaryOperator::Div => (left / right).into(),
             BinaryOperator::Mod => (left % right).into(),
+            BinaryOperator::Pow => (left.powf(right)).into(),
         };
 
         Ok(MemoryItem::UserVal(UserVal {
@@ -2257,13 +2258,46 @@ pub enum BinaryOperator {
     #[serde(rename = "%")]
     #[display("%")]
     Mod,
+    /// Raise a number to a power.
+    #[serde(rename = "^")]
+    #[display("^")]
+    Pow,
+}
+
+/// Mathematical associativity.
+/// Should a . b . c be read as (a . b) . c, or a . (b . c)
+/// See <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Operator_precedence#precedence_and_associativity> for more.
+#[derive(PartialEq, Eq, Debug, Clone, Copy)]
+pub enum Associativity {
+    /// Read a . b . c as (a . b) . c
+    Left,
+    /// Read a . b . c as a . (b . c)
+    Right,
+}
+
+impl Associativity {
+    pub fn is_left(&self) -> bool {
+        matches!(self, Self::Left)
+    }
 }
 
 impl BinaryOperator {
+    /// Follow JS definitions of each operator.
+    /// Taken from <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Operator_precedence#table>
     pub fn precedence(&self) -> u8 {
         match &self {
             BinaryOperator::Add | BinaryOperator::Sub => 11,
             BinaryOperator::Mul | BinaryOperator::Div | BinaryOperator::Mod => 12,
+            BinaryOperator::Pow => 6,
+        }
+    }
+
+    /// Follow JS definitions of each operator.
+    /// Taken from <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Operator_precedence#table>
+    pub fn associativity(&self) -> Associativity {
+        match self {
+            Self::Add | Self::Sub | Self::Mul | Self::Div | Self::Mod => Associativity::Left,
+            Self::Pow => Associativity::Right,
         }
     }
 }

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

@@ -5,7 +5,6 @@ pub mod docs;
 pub mod engine;
 pub mod errors;
 pub mod executor;
-pub mod math_parser;
 pub mod parser;
 pub mod server;
 pub mod std;

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

@@ -0,0 +1,134 @@
+use crate::ast::types::{BinaryExpression, BinaryOperator, BinaryPart};
+
+/// Parses a list of tokens (in infix order, i.e. as the user typed them)
+/// into a binary expression tree.
+pub fn parse(infix_tokens: Vec<BinaryExpressionToken>) -> BinaryExpression {
+    let rpn = postfix(infix_tokens);
+    evaluate(rpn)
+}
+
+/// Parses a list of tokens (in postfix order) into a binary expression tree.
+fn evaluate(rpn: Vec<BinaryExpressionToken>) -> BinaryExpression {
+    let mut operand_stack = Vec::new();
+    for item in rpn {
+        let expr = match item {
+            BinaryExpressionToken::Operator(operator) => {
+                let right: BinaryPart = operand_stack.pop().unwrap();
+                let left = operand_stack.pop().unwrap();
+                BinaryPart::BinaryExpression(Box::new(BinaryExpression {
+                    start: left.start(),
+                    end: right.end(),
+                    operator,
+                    left,
+                    right,
+                }))
+            }
+            BinaryExpressionToken::Operand(o) => o,
+        };
+        operand_stack.push(expr)
+    }
+    if let BinaryPart::BinaryExpression(expr) = operand_stack.pop().unwrap() {
+        *expr
+    } else {
+        panic!("Last expression was not a binary expression")
+    }
+}
+
+/// Reorders tokens from infix order to postfix order.
+fn postfix(infix: Vec<BinaryExpressionToken>) -> Vec<BinaryExpressionToken> {
+    let mut operator_stack: Vec<BinaryOperator> = Vec::with_capacity(infix.len());
+    let mut output = Vec::with_capacity(infix.len());
+    for token in infix {
+        match token {
+            BinaryExpressionToken::Operator(o1) => {
+                // From https://en.wikipedia.org/wiki/Shunting_yard_algorithm:
+                // while (
+                //     there is an operator o2 at the top of the operator stack which is not a left parenthesis,
+                //     and (o2 has greater precedence than o1 or (o1 and o2 have the same precedence and o1 is left-associative))
+                // )
+                while operator_stack
+                    .last()
+                    .map(|o2| {
+                        (o2.precedence() > o1.precedence())
+                            || o1.precedence() == o2.precedence() && o1.associativity().is_left()
+                    })
+                    .unwrap_or(false)
+                {
+                    output.push(BinaryExpressionToken::Operator(operator_stack.pop().unwrap()));
+                }
+                operator_stack.push(o1);
+            }
+            o @ BinaryExpressionToken::Operand(_) => output.push(o),
+        }
+    }
+    // After the while loop, pop the remaining items from the operator stack into the output queue.
+    output.extend(operator_stack.into_iter().rev().map(BinaryExpressionToken::Operator));
+    output
+}
+
+/// Expressions are made up of operators and operands.
+#[derive(PartialEq, Debug)]
+pub enum BinaryExpressionToken {
+    Operator(BinaryOperator),
+    Operand(BinaryPart),
+}
+
+impl From<BinaryPart> for BinaryExpressionToken {
+    fn from(value: BinaryPart) -> Self {
+        Self::Operand(value)
+    }
+}
+
+impl From<BinaryOperator> for BinaryExpressionToken {
+    fn from(value: BinaryOperator) -> Self {
+        Self::Operator(value)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::ast::types::Literal;
+
+    use super::*;
+
+    #[test]
+    fn parse_and_evaluate() {
+        /// Make a literal
+        fn lit(n: u8) -> BinaryPart {
+            BinaryPart::Literal(Box::new(Literal {
+                start: 0,
+                end: 0,
+                value: n.into(),
+                raw: n.to_string(),
+            }))
+        }
+        let tests: Vec<Vec<BinaryExpressionToken>> = vec![
+            // 3 + 4 × 2 ÷ ( 1 − 5 ) ^ 2 ^ 3
+            vec![
+                lit(3).into(),
+                BinaryOperator::Add.into(),
+                lit(4).into(),
+                BinaryOperator::Mul.into(),
+                lit(2).into(),
+                BinaryOperator::Div.into(),
+                BinaryPart::BinaryExpression(Box::new(BinaryExpression {
+                    start: 0,
+                    end: 0,
+                    operator: BinaryOperator::Sub,
+                    left: lit(1),
+                    right: lit(5),
+                }))
+                .into(),
+                BinaryOperator::Pow.into(),
+                lit(2).into(),
+                BinaryOperator::Pow.into(),
+                lit(3).into(),
+            ],
+        ];
+        for infix_input in tests {
+            let rpn = postfix(infix_input);
+            let tree = evaluate(rpn);
+            dbg!(tree);
+        }
+    }
+}

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

@@ -17,12 +17,13 @@ use crate::{
     },
     errors::{KclError, KclErrorDetails},
     executor::SourceRange,
-    math_parser::MathParser,
     parser::parser_impl::error::ContextError,
     std::StdLib,
     token::{Token, TokenType},
 };
 
+use super::{math::BinaryExpressionToken, PIPE_OPERATOR, PIPE_SUBSTITUTION_OPERATOR};
+
 mod error;
 
 type PResult<O, E = error::ContextError> = winnow::prelude::PResult<O, E>;
@@ -455,7 +456,7 @@ fn object(i: TokenSlice) -> PResult<ObjectExpression> {
 /// Parse the % symbol, used to substitute a curried argument from a |> (pipe).
 fn pipe_sub(i: TokenSlice) -> PResult<PipeSubstitution> {
     any.try_map(|token: Token| {
-        if matches!(token.token_type, TokenType::Operator) && token.value == "%" {
+        if matches!(token.token_type, TokenType::Operator) && token.value == PIPE_SUBSTITUTION_OPERATOR {
             Ok(PipeSubstitution {
                 start: token.start,
                 end: token.end,
@@ -1025,35 +1026,33 @@ fn unary_expression(i: TokenSlice) -> PResult<UnaryExpression> {
 /// Consume tokens that make up a binary expression, but don't actually return them.
 /// Why not?
 /// Because this is designed to be used with .recognize() within the `binary_expression` parser.
-fn binary_expression_tokens(i: TokenSlice) -> PResult<()> {
-    let _first = operand.parse_next(i)?;
-    let _remaining: Vec<_> = repeat(
+fn binary_expression_tokens(i: TokenSlice) -> PResult<Vec<BinaryExpressionToken>> {
+    let first = operand.parse_next(i).map(BinaryExpressionToken::from)?;
+    let remaining: Vec<_> = repeat(
         1..,
         (
-            preceded(opt(whitespace), binary_operator),
-            preceded(opt(whitespace), operand),
+            preceded(opt(whitespace), binary_operator).map(BinaryExpressionToken::from),
+            preceded(opt(whitespace), operand).map(BinaryExpressionToken::from),
         ),
     )
     .context(expected(
         "one or more binary operators (like + or -) and operands for them, e.g. 1 + 2 - 3",
     ))
     .parse_next(i)?;
-    Ok(())
+    let mut out = Vec::with_capacity(1 + 2 * remaining.len());
+    out.push(first);
+    out.extend(remaining.into_iter().flat_map(|(a, b)| [a, b]));
+    Ok(out)
 }
 
 /// Parse an infix binary expression.
 fn binary_expression(i: TokenSlice) -> PResult<BinaryExpression> {
     // Find the slice of tokens which makes up the binary expression
-    let tokens = binary_expression_tokens.recognize().parse_next(i)?;
+    let tokens = binary_expression_tokens.parse_next(i)?;
 
     // Pass the token slice into the specialized math parser, for things like
     // precedence and converting infix operations to an AST.
-    let mut math_parser = MathParser::new(tokens);
-    let expr = math_parser
-        .parse()
-        .map_err(error::ContextError::from)
-        .map_err(ErrMode::Backtrack)?;
-    Ok(expr)
+    Ok(super::math::parse(tokens))
 }
 
 fn binary_expr_in_parens(i: TokenSlice) -> PResult<BinaryExpression> {
@@ -1134,7 +1133,7 @@ fn big_arrow(i: TokenSlice) -> PResult<Token> {
 }
 /// Parse a |> operator.
 fn pipe_operator(i: TokenSlice) -> PResult<Token> {
-    one_of((TokenType::Operator, "|>"))
+    one_of((TokenType::Operator, PIPE_OPERATOR))
         .context(expected(
             "the |> operator, used for 'piping' one function's output into another function's input",
         ))
@@ -1757,19 +1756,11 @@ const mySk1 = startSketchAt([0, 0])"#;
         {
             // Run the original parser
             let tokens = crate::token::lexer(test_program);
-            let expected = crate::parser::Parser::new(tokens.clone())
-                .ast_old()
-                .expect("Old parser failed");
-
-            // Run the second parser, check it matches the first parser.
-            let actual = match program.parse(&tokens) {
+            // TODO: get snapshots of what this outputs.
+            let _actual = match program.parse(&tokens) {
                 Ok(x) => x,
                 Err(_e) => panic!("could not parse test {i}"),
             };
-            assert_eq!(
-                expected, actual,
-                "old parser (left) and new parser (right) disagree on test {i}"
-            );
         }
     }
 
@@ -2064,4 +2055,702 @@ const mySk1 = startSketchAt([0, 0])"#;
             assert_eq!(value.raw, "5");
         }
     }
+
+    #[test]
+    fn test_math_parse() {
+        let tokens = crate::token::lexer(r#"5 + "a""#);
+        let actual = crate::parser::Parser::new(tokens).ast().unwrap().body;
+        let expr = BinaryExpression {
+            start: 0,
+            end: 7,
+            operator: BinaryOperator::Add,
+            left: BinaryPart::Literal(Box::new(Literal {
+                start: 0,
+                end: 1,
+                value: serde_json::Value::Number(serde_json::Number::from(5)),
+                raw: "5".to_owned(),
+            })),
+            right: BinaryPart::Literal(Box::new(Literal {
+                start: 4,
+                end: 7,
+                value: serde_json::Value::String("a".to_owned()),
+                raw: r#""a""#.to_owned(),
+            })),
+        };
+        let expected = vec![BodyItem::ExpressionStatement(ExpressionStatement {
+            start: 0,
+            end: 7,
+            expression: Value::BinaryExpression(Box::new(expr)),
+        })];
+        assert_eq!(expected, actual);
+    }
+
+    #[test]
+    fn test_is_code_token() {
+        let tokens = [
+            Token {
+                token_type: TokenType::Word,
+                start: 0,
+                end: 3,
+                value: "log".to_string(),
+            },
+            Token {
+                token_type: TokenType::Brace,
+                start: 3,
+                end: 4,
+                value: "(".to_string(),
+            },
+            Token {
+                token_type: TokenType::Number,
+                start: 4,
+                end: 5,
+                value: "5".to_string(),
+            },
+            Token {
+                token_type: TokenType::Comma,
+                start: 5,
+                end: 6,
+                value: ",".to_string(),
+            },
+            Token {
+                token_type: TokenType::String,
+                start: 7,
+                end: 14,
+                value: "\"hello\"".to_string(),
+            },
+            Token {
+                token_type: TokenType::Word,
+                start: 16,
+                end: 27,
+                value: "aIdentifier".to_string(),
+            },
+            Token {
+                token_type: TokenType::Brace,
+                start: 27,
+                end: 28,
+                value: ")".to_string(),
+            },
+        ];
+        for (i, token) in tokens.iter().enumerate() {
+            assert!(token.is_code_token(), "failed test {i}: {token:?}")
+        }
+    }
+
+    #[test]
+    fn test_is_not_code_token() {
+        let tokens = [
+            Token {
+                token_type: TokenType::Whitespace,
+                start: 6,
+                end: 7,
+                value: " ".to_string(),
+            },
+            Token {
+                token_type: TokenType::BlockComment,
+                start: 28,
+                end: 30,
+                value: "/* abte */".to_string(),
+            },
+            Token {
+                token_type: TokenType::LineComment,
+                start: 30,
+                end: 33,
+                value: "// yoyo a line".to_string(),
+            },
+        ];
+        for (i, token) in tokens.iter().enumerate() {
+            assert!(!token.is_code_token(), "failed test {i}: {token:?}")
+        }
+    }
+
+    #[test]
+    fn test_abstract_syntax_tree() {
+        let code = "5 +6";
+        let parser = crate::parser::Parser::new(crate::token::lexer(code));
+        let result = parser.ast().unwrap();
+        let expected_result = Program {
+            start: 0,
+            end: 4,
+            body: vec![BodyItem::ExpressionStatement(ExpressionStatement {
+                start: 0,
+                end: 4,
+                expression: Value::BinaryExpression(Box::new(BinaryExpression {
+                    start: 0,
+                    end: 4,
+                    left: BinaryPart::Literal(Box::new(Literal {
+                        start: 0,
+                        end: 1,
+                        value: serde_json::Value::Number(serde_json::Number::from(5)),
+                        raw: "5".to_string(),
+                    })),
+                    operator: BinaryOperator::Add,
+                    right: BinaryPart::Literal(Box::new(Literal {
+                        start: 3,
+                        end: 4,
+                        value: serde_json::Value::Number(serde_json::Number::from(6)),
+                        raw: "6".to_string(),
+                    })),
+                })),
+            })],
+            non_code_meta: NonCodeMeta::default(),
+        };
+
+        assert_eq!(result, expected_result);
+    }
+
+    #[test]
+    fn test_empty_file() {
+        let some_program_string = r#""#;
+        let tokens = crate::token::lexer(some_program_string);
+        let parser = crate::parser::Parser::new(tokens);
+        let result = parser.ast();
+        assert!(result.is_err());
+        assert!(result.err().unwrap().to_string().contains("file is empty"));
+    }
+
+    #[test]
+    fn test_parse_half_pipe_small() {
+        let tokens = crate::token::lexer(
+            "const secondExtrude = startSketchOn('XY')
+  |> startProfileAt([0,0], %)
+  |",
+        );
+        let parser = crate::parser::Parser::new(tokens);
+        let result = parser.ast();
+        assert!(result.is_err());
+        assert!(result.err().unwrap().to_string().contains("Unexpected token"));
+    }
+
+    #[test]
+    fn test_parse_member_expression_double_nested_braces() {
+        let tokens = crate::token::lexer(r#"const prop = yo["one"][two]"#);
+        let parser = crate::parser::Parser::new(tokens);
+        parser.ast().unwrap();
+    }
+
+    #[test]
+    fn test_parse_member_expression_binary_expression_period_number_first() {
+        let tokens = crate::token::lexer(
+            r#"const obj = { a: 1, b: 2 }
+const height = 1 - obj.a"#,
+        );
+        let parser = crate::parser::Parser::new(tokens);
+        parser.ast().unwrap();
+    }
+
+    #[test]
+    fn test_parse_member_expression_binary_expression_brace_number_first() {
+        let tokens = crate::token::lexer(
+            r#"const obj = { a: 1, b: 2 }
+const height = 1 - obj["a"]"#,
+        );
+        let parser = crate::parser::Parser::new(tokens);
+        parser.ast().unwrap();
+    }
+
+    #[test]
+    fn test_parse_member_expression_binary_expression_brace_number_second() {
+        let tokens = crate::token::lexer(
+            r#"const obj = { a: 1, b: 2 }
+const height = obj["a"] - 1"#,
+        );
+        let parser = crate::parser::Parser::new(tokens);
+        parser.ast().unwrap();
+    }
+
+    #[test]
+    fn test_parse_member_expression_binary_expression_in_array_number_first() {
+        let tokens = crate::token::lexer(
+            r#"const obj = { a: 1, b: 2 }
+const height = [1 - obj["a"], 0]"#,
+        );
+        let parser = crate::parser::Parser::new(tokens);
+        parser.ast().unwrap();
+    }
+
+    #[test]
+    fn test_parse_member_expression_binary_expression_in_array_number_second() {
+        let tokens = crate::token::lexer(
+            r#"const obj = { a: 1, b: 2 }
+const height = [obj["a"] - 1, 0]"#,
+        );
+        let parser = crate::parser::Parser::new(tokens);
+        parser.ast().unwrap();
+    }
+
+    #[test]
+    fn test_parse_member_expression_binary_expression_in_array_number_second_missing_space() {
+        let tokens = crate::token::lexer(
+            r#"const obj = { a: 1, b: 2 }
+const height = [obj["a"] -1, 0]"#,
+        );
+        let parser = crate::parser::Parser::new(tokens);
+        parser.ast().unwrap();
+    }
+
+    #[test]
+    fn test_parse_half_pipe() {
+        let tokens = crate::token::lexer(
+            "const height = 10
+
+const firstExtrude = startSketchOn('XY')
+  |> startProfileAt([0,0], %)
+  |> line([0, 8], %)
+  |> line([20, 0], %)
+  |> line([0, -8], %)
+  |> close(%)
+  |> extrude(2, %)
+
+show(firstExtrude)
+
+const secondExtrude = startSketchOn('XY')
+  |> startProfileAt([0,0], %)
+  |",
+        );
+        let parser = crate::parser::Parser::new(tokens);
+        let result = parser.ast();
+        assert!(result.is_err());
+        assert!(result.err().unwrap().to_string().contains("Unexpected token"));
+    }
+
+    #[test]
+    fn test_parse_greater_bang() {
+        let tokens = crate::token::lexer(">!");
+        let parser = crate::parser::Parser::new(tokens);
+        let err = parser.ast().unwrap_err();
+        // TODO: Better errors when program cannot tokenize.
+        // https://github.com/KittyCAD/modeling-app/issues/696
+        assert!(err.to_string().contains("file is empty"));
+    }
+
+    #[test]
+    fn test_parse_z_percent_parens() {
+        let tokens = crate::token::lexer("z%)");
+        let parser = crate::parser::Parser::new(tokens);
+        let result = parser.ast();
+        assert!(result.is_err());
+        assert!(result.err().unwrap().to_string().contains("Unexpected token"));
+    }
+
+    #[test]
+    fn test_parse_parens_unicode() {
+        let tokens = crate::token::lexer("(ޜ");
+        let parser = crate::parser::Parser::new(tokens);
+        let result = parser.ast();
+        // TODO: Better errors when program cannot tokenize.
+        // https://github.com/KittyCAD/modeling-app/issues/696
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_parse_negative_in_array_binary_expression() {
+        let tokens = crate::token::lexer(
+            r#"const leg1 = 5
+const thickness = 0.56
+
+const bracket = [-leg2 + thickness, 0]
+"#,
+        );
+        let parser = crate::parser::Parser::new(tokens);
+        let result = parser.ast();
+        assert!(result.is_ok());
+    }
+
+    #[test]
+    fn test_parse_nested_open_brackets() {
+        let tokens = crate::token::lexer(
+            r#"
+z(-[["#,
+        );
+        let parser = crate::parser::Parser::new(tokens);
+        let result = parser.ast();
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_parse_weird_new_line_function() {
+        let tokens = crate::token::lexer(
+            r#"z
+ (--#"#,
+        );
+        let parser = crate::parser::Parser::new(tokens);
+        let result = parser.ast();
+        assert!(result.is_err());
+        // TODO: Better errors when program cannot tokenize.
+        // https://github.com/KittyCAD/modeling-app/issues/696
+        assert_eq!(
+            result.err().unwrap().to_string(),
+            r#"syntax: KclErrorDetails { source_ranges: [], message: "file is empty" }"#
+        );
+    }
+
+    #[test]
+    fn test_parse_weird_lots_of_fancy_brackets() {
+        let tokens = crate::token::lexer(r#"zz({{{{{{{{)iegAng{{{{{{{##"#);
+        let parser = crate::parser::Parser::new(tokens);
+        let result = parser.ast();
+        assert!(result.is_err());
+        // TODO: Better errors when program cannot tokenize.
+        // https://github.com/KittyCAD/modeling-app/issues/696
+        assert_eq!(
+            result.err().unwrap().to_string(),
+            r#"syntax: KclErrorDetails { source_ranges: [], message: "file is empty" }"#
+        );
+    }
+
+    #[test]
+    fn test_parse_weird_close_before_open() {
+        let tokens = crate::token::lexer(
+            r#"fn)n
+e
+["#,
+        );
+        let parser = crate::parser::Parser::new(tokens);
+        let result = parser.ast();
+        assert!(result.is_err());
+        assert!(result
+            .err()
+            .unwrap()
+            .to_string()
+            .contains("expected whitespace, found ')' which is brace"));
+    }
+
+    #[test]
+    fn test_parse_weird_close_before_nada() {
+        let tokens = crate::token::lexer(r#"fn)n-"#);
+        let parser = crate::parser::Parser::new(tokens);
+        let result = parser.ast();
+        assert!(result.is_err());
+        assert!(result
+            .err()
+            .unwrap()
+            .to_string()
+            .contains("expected whitespace, found ')' which is brace"));
+    }
+
+    #[test]
+    fn test_parse_weird_lots_of_slashes() {
+        let tokens = crate::token::lexer(
+            r#"J///////////o//+///////////P++++*++++++P///////˟
+++4"#,
+        );
+        let parser = crate::parser::Parser::new(tokens);
+        let result = parser.ast();
+        assert!(result.is_err());
+        assert!(result.err().unwrap().to_string().contains("Unexpected token"));
+    }
+
+    #[test]
+    fn test_parse_expand_array() {
+        let code = "const myArray = [0..10]";
+        let parser = crate::parser::Parser::new(crate::token::lexer(code));
+        let result = parser.ast().unwrap();
+        let expected_result = Program {
+            start: 0,
+            end: 23,
+            body: vec![BodyItem::VariableDeclaration(VariableDeclaration {
+                start: 0,
+                end: 23,
+                declarations: vec![VariableDeclarator {
+                    start: 6,
+                    end: 23,
+                    id: Identifier {
+                        start: 6,
+                        end: 13,
+                        name: "myArray".to_string(),
+                    },
+                    init: Value::ArrayExpression(Box::new(ArrayExpression {
+                        start: 16,
+                        end: 23,
+                        elements: vec![
+                            Value::Literal(Box::new(Literal {
+                                start: 17,
+                                end: 18,
+                                value: 0.into(),
+                                raw: "0".to_string(),
+                            })),
+                            Value::Literal(Box::new(Literal {
+                                start: 17,
+                                end: 18,
+                                value: 1.into(),
+                                raw: "1".to_string(),
+                            })),
+                            Value::Literal(Box::new(Literal {
+                                start: 17,
+                                end: 18,
+                                value: 2.into(),
+                                raw: "2".to_string(),
+                            })),
+                            Value::Literal(Box::new(Literal {
+                                start: 17,
+                                end: 18,
+                                value: 3.into(),
+                                raw: "3".to_string(),
+                            })),
+                            Value::Literal(Box::new(Literal {
+                                start: 17,
+                                end: 18,
+                                value: 4.into(),
+                                raw: "4".to_string(),
+                            })),
+                            Value::Literal(Box::new(Literal {
+                                start: 17,
+                                end: 18,
+                                value: 5.into(),
+                                raw: "5".to_string(),
+                            })),
+                            Value::Literal(Box::new(Literal {
+                                start: 17,
+                                end: 18,
+                                value: 6.into(),
+                                raw: "6".to_string(),
+                            })),
+                            Value::Literal(Box::new(Literal {
+                                start: 17,
+                                end: 18,
+                                value: 7.into(),
+                                raw: "7".to_string(),
+                            })),
+                            Value::Literal(Box::new(Literal {
+                                start: 17,
+                                end: 18,
+                                value: 8.into(),
+                                raw: "8".to_string(),
+                            })),
+                            Value::Literal(Box::new(Literal {
+                                start: 17,
+                                end: 18,
+                                value: 9.into(),
+                                raw: "9".to_string(),
+                            })),
+                            Value::Literal(Box::new(Literal {
+                                start: 17,
+                                end: 18,
+                                value: 10.into(),
+                                raw: "10".to_string(),
+                            })),
+                        ],
+                    })),
+                }],
+                kind: VariableKind::Const,
+            })],
+            non_code_meta: NonCodeMeta::default(),
+        };
+
+        assert_eq!(result, expected_result);
+    }
+
+    #[test]
+    fn test_error_keyword_in_variable() {
+        let some_program_string = r#"const let = "thing""#;
+        let tokens = crate::token::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([6, 9])], message: "Cannot assign a variable to a reserved keyword: let" }"#
+        );
+    }
+
+    #[test]
+    fn test_error_keyword_in_fn_name() {
+        let some_program_string = r#"fn let = () {}"#;
+        let tokens = crate::token::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: let" }"#
+        );
+    }
+
+    #[test]
+    fn test_error_stdlib_in_fn_name() {
+        let some_program_string = r#"fn cos = () => {
+            return 1
+        }"#;
+        let tokens = crate::token::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) => {
+    return 1
+}"#;
+        let tokens = crate::token::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: let" }"#
+        );
+    }
+
+    #[test]
+    fn test_error_stdlib_in_fn_args() {
+        let some_program_string = r#"fn thing = (cos) => {
+    return 1
+}"#;
+        let tokens = crate::token::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 zero_param_function() {
+        let program = r#"
+        fn firstPrimeNumber = () => {
+            return 2
+        }
+        firstPrimeNumber()
+        "#;
+        let tokens = crate::token::lexer(program);
+        let parser = crate::parser::Parser::new(tokens);
+        let _ast = parser.ast().unwrap();
+    }
+
+    #[test]
+    fn test_keyword_ok_in_fn_args_return() {
+        let some_program_string = r#"fn thing = (param) => {
+    return true
+}
+
+thing(false)
+"#;
+        let tokens = crate::token::lexer(some_program_string);
+        let parser = crate::parser::Parser::new(tokens);
+        parser.ast().unwrap();
+    }
+
+    #[test]
+    fn test_error_define_function_as_var() {
+        for name in ["var", "let", "const"] {
+            let some_program_string = format!(
+                r#"{} thing = (param) => {{
+    return true
+}}
+
+thing(false)
+"#,
+                name
+            );
+            let tokens = crate::token::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(),
+                format!(
+                    r#"syntax: KclErrorDetails {{ source_ranges: [SourceRange([0, {}])], message: "Expected a `fn` variable kind, found: `{}`" }}"#,
+                    name.len(),
+                    name
+                )
+            );
+        }
+    }
+
+    #[test]
+    fn test_error_define_var_as_function() {
+        let some_program_string = r#"fn thing = "thing""#;
+        let tokens = crate::token::lexer(some_program_string);
+        let parser = crate::parser::Parser::new(tokens);
+        let result = parser.ast();
+        assert!(result.is_err());
+        // TODO: https://github.com/KittyCAD/modeling-app/issues/784
+        // Improve this error message.
+        // It should say that the compiler is expecting a function expression on the RHS.
+        assert_eq!(
+            result.err().unwrap().to_string(),
+            r#"syntax: KclErrorDetails { source_ranges: [SourceRange([11, 18])], message: "Unexpected token" }"#
+        );
+    }
+
+    #[test]
+    fn test_member_expression_sketch_group() {
+        let some_program_string = r#"fn cube = (pos, scale) => {
+  const sg = startSketchOn('XY')
+  |> startProfileAt(pos, %)
+    |> line([0, scale], %)
+    |> line([scale, 0], %)
+    |> line([0, -scale], %)
+
+  return sg
+}
+
+const b1 = cube([0,0], 10)
+const b2 = cube([3,3], 4)
+
+const pt1 = b1[0]
+const pt2 = b2[0]
+
+show(b1)
+show(b2)"#;
+        let tokens = crate::token::lexer(some_program_string);
+        let parser = crate::parser::Parser::new(tokens);
+        parser.ast().unwrap();
+    }
+
+    #[test]
+    fn test_math_with_stdlib() {
+        let some_program_string = r#"const d2r = pi() / 2
+let other_thing = 2 * cos(3)"#;
+        let tokens = crate::token::lexer(some_program_string);
+        let parser = crate::parser::Parser::new(tokens);
+        parser.ast().unwrap();
+    }
+
+    #[test]
+    fn test_negative_arguments() {
+        let some_program_string = r#"fn box = (p, h, l, w) => {
+ const myBox = startSketchOn('XY')
+    |> startProfileAt(p, %)
+    |> line([0, l], %)
+    |> line([w, 0], %)
+    |> line([0, -l], %)
+    |> close(%)
+    |> extrude(h, %)
+
+  return myBox
+}
+let myBox = box([0,0], -3, -16, -10)
+show(myBox)"#;
+        let tokens = crate::token::lexer(some_program_string);
+        let parser = crate::parser::Parser::new(tokens);
+        parser.ast().unwrap();
+    }
+
+    #[test]
+    fn test_math() {
+        for math_expression in [
+            "1 + 2",
+            "1+2",
+            "1 -2",
+            "1 + 2 * 3",
+            "1 * ( 2 + 3 )",
+            "1 * ( 2 + 3 ) / 4",
+            "1 + ( 2 + 3 ) / 4",
+            "1 * (( 2 + 3 ) / 4 + 5 )",
+            "1 * ((( 2 + 3 )))",
+            "distance * p * FOS * 6 / (sigmaAllow * width)",
+            "2 + (((3)))",
+        ] {
+            let tokens = crate::token::lexer(math_expression);
+            let _expr = binary_expression.parse(&tokens).unwrap();
+        }
+    }
 }