Remove enums that only existed for optional tags

Part of https://github.com/KittyCAD/modeling-app/issues/1006#issuecomment-1816978586

This adds support for optional parameters to the AST. They are declared with a ? suffix, e.g. `(x, tag?) => {...}`.

This PR does not actually _use_ these optional parameters anywhere. In particular, it does not change the KCL stdlib or any existing function definitions. That will happen in a follow-up PR.

package.json

@@ -112,7 +112,7 @@
     "@types/wicg-file-system-access": "^2020.9.6",
     "@types/ws": "^8.5.5",
     "@vitejs/plugin-react": "^4.1.1",
-    "@vitest/coverage-istanbul": "^0.34.1",
+    "@vitest/coverage-istanbul": "^0.34.6",
     "autoprefixer": "^10.4.13",
     "eslint": "^8.53.0",
     "eslint-config-react-app": "^7.0.1",

src-tauri/Cargo.lock

@@ -1913,6 +1913,12 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"
 
+[[package]]
+name = "minisign-verify"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "933dca44d65cdd53b355d0b73d380a2ff5da71f87f036053188bf1eab6a19881"
+
 [[package]]
 name = "miniz_oxide"
 version = "0.6.2"
@@ -3106,9 +3112,9 @@ dependencies = [
 
 [[package]]
 name = "schemars"
-version = "0.8.15"
+version = "0.8.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1f7b0ce13155372a76ee2e1c5ffba1fe61ede73fbea5630d61eee6fac4929c0c"
+checksum = "45a28f4c49489add4ce10783f7911893516f15afe45d015608d41faca6bc4d29"
 dependencies = [
  "bigdecimal",
  "bytes",
@@ -3123,9 +3129,9 @@ dependencies = [
 
 [[package]]
 name = "schemars_derive"
-version = "0.8.15"
+version = "0.8.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e85e2a16b12bdb763244c69ab79363d71db2b4b918a2def53f80b02e0574b13c"
+checksum = "c767fd6fa65d9ccf9cf026122c1b555f2ef9a4f0cea69da4d7dbc3e258d30967"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -3739,6 +3745,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9bfe673cf125ef364d6f56b15e8ce7537d9ca7e4dae1cf6fbbdeed2e024db3d9"
 dependencies = [
  "anyhow",
+ "base64 0.21.2",
  "bytes",
  "cocoa",
  "dirs-next",
@@ -3752,6 +3759,7 @@ dependencies = [
  "heck 0.4.1",
  "http",
  "ignore",
+ "minisign-verify",
  "objc",
  "once_cell",
  "open",
@@ -3776,12 +3784,14 @@ dependencies = [
  "tauri-utils",
  "tempfile",
  "thiserror",
+ "time",
  "tokio",
  "url",
  "uuid",
  "webkit2gtk",
  "webview2-com",
  "windows 0.39.0",
+ "zip",
 ]
 
 [[package]]
@@ -3846,7 +3856,7 @@ dependencies = [
 [[package]]
 name = "tauri-plugin-fs-extra"
 version = "0.0.0"
-source = "git+https://github.com/tauri-apps/plugins-workspace?branch=v1#61e862597e7234ddca9d9c4b07700855841888f3"
+source = "git+https://github.com/tauri-apps/plugins-workspace?branch=v1#642a195d34ec5bf6bbc780dde9c02fca33e1bd00"
 dependencies = [
  "log",
  "serde",
@@ -5002,3 +5012,14 @@ checksum = "56c1936c4cc7a1c9ab21a1ebb602eb942ba868cbd44a99cb7cdc5892335e1c85"
 dependencies = [
  "linked-hash-map",
 ]
+
+[[package]]
+name = "zip"
+version = "0.6.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "760394e246e4c28189f19d488c058bf16f564016aefac5d32bb1f3b51d5e9261"
+dependencies = [
+ "byteorder",
+ "crc32fast",
+ "crossbeam-utils",
+]

src/lang/abstractSyntaxTree.test.ts

@@ -169,16 +169,24 @@ describe('testing function declaration', () => {
               end: 39,
               params: [
                 {
-                  type: 'Identifier',
+                  type: 'Parameter',
-                  start: 12,
+                  identifier: {
-                  end: 13,
+                    type: 'Identifier',
-                  name: 'a',
+                    start: 12,
+                    end: 13,
+                    name: 'a',
+                  },
+                  optional: false,
                 },
                 {
-                  type: 'Identifier',
+                  type: 'Parameter',
-                  start: 15,
+                  identifier: {
-                  end: 16,
+                    type: 'Identifier',
-                  name: 'b',
+                    start: 15,
+                    end: 16,
+                    name: 'b',
+                  },
+                  optional: false,
                 },
               ],
               body: {
@@ -244,16 +252,24 @@ const myVar = funcN(1, 2)`
               end: 37,
               params: [
                 {
-                  type: 'Identifier',
+                  type: 'Parameter',
-                  start: 12,
+                  identifier: {
-                  end: 13,
+                    type: 'Identifier',
-                  name: 'a',
+                    start: 12,
+                    end: 13,
+                    name: 'a',
+                  },
+                  optional: false,
                 },
                 {
-                  type: 'Identifier',
+                  type: 'Parameter',
-                  start: 15,
+                  identifier: {
-                  end: 16,
+                    type: 'Identifier',
-                  name: 'b',
+                    start: 15,
+                    end: 16,
+                    name: 'b',
+                  },
+                  optional: false,
                 },
               ],
               body: {

src/lang/getNodePathFromSourceRange.test.ts

@@ -1,5 +1,5 @@
 import { getNodePathFromSourceRange, getNodeFromPath } from './queryAst'
-import { Identifier, parse, initPromise } from './wasm'
+import { Identifier, parse, initPromise, Parameter } from './wasm'
 
 beforeAll(() => initPromise)
 
@@ -46,7 +46,7 @@ const b1 = cube([0,0], 10)`
 
     const ast = parse(code)
     const nodePath = getNodePathFromSourceRange(ast, sourceRange)
-    const node = getNodeFromPath<Identifier>(ast, nodePath).node
+    const node = getNodeFromPath<Parameter>(ast, nodePath).node
 
     expect(nodePath).toEqual([
       ['body', ''],
@@ -57,8 +57,8 @@ const b1 = cube([0,0], 10)`
       ['params', 'FunctionExpression'],
       [0, 'index'],
     ])
-    expect(node.type).toBe('Identifier')
+    expect(node.type).toBe('Parameter')
-    expect(node.name).toBe('pos')
+    expect(node.identifier.name).toBe('pos')
   })
   it('gets path right for deep within function definition body', () => {
     const code = `fn cube = (pos, scale) => {

src/lang/queryAst.ts

@@ -247,10 +247,10 @@ function moreNodePathFromSourceRange(
   if (_node.type === 'FunctionExpression' && isInRange) {
     for (let i = 0; i < _node.params.length; i++) {
       const param = _node.params[i]
-      if (param.start <= start && param.end >= end) {
+      if (param.identifier.start <= start && param.identifier.end >= end) {
         path.push(['params', 'FunctionExpression'])
         path.push([i, 'index'])
-        return moreNodePathFromSourceRange(param, sourceRange, path)
+        return moreNodePathFromSourceRange(param.identifier, sourceRange, path)
       }
     }
     if (_node.body.start <= start && _node.body.end >= end) {

src/lang/wasm.ts

@@ -20,6 +20,7 @@ export type { ObjectExpression } from '../wasm-lib/kcl/bindings/ObjectExpression
 export type { MemberExpression } from '../wasm-lib/kcl/bindings/MemberExpression'
 export type { PipeExpression } from '../wasm-lib/kcl/bindings/PipeExpression'
 export type { VariableDeclaration } from '../wasm-lib/kcl/bindings/VariableDeclaration'
+export type { Parameter } from '../wasm-lib/kcl/bindings/Parameter'
 export type { PipeSubstitution } from '../wasm-lib/kcl/bindings/PipeSubstitution'
 export type { Identifier } from '../wasm-lib/kcl/bindings/Identifier'
 export type { UnaryExpression } from '../wasm-lib/kcl/bindings/UnaryExpression'

src/wasm-lib/Cargo.lock

@@ -683,21 +683,20 @@ checksum = "c2e66c9d817f1720209181c316d28635c050fa304f9c79e47a520882661b7308"
 
 [[package]]
 name = "databake"
-version = "0.1.6"
+version = "0.1.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "959b676312ba1aaafb2219c475560082e6b20c3bc572ec1483f93cecd748cf3d"
+checksum = "82175d72e69414ceafbe2b49686794d3a8bed846e0d50267355f83ea8fdd953a"
 dependencies = [
  "databake-derive",
  "proc-macro2",
  "quote",
- "syn 2.0.39",
 ]
 
 [[package]]
 name = "databake-derive"
-version = "0.1.6"
+version = "0.1.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5f0694dfe255f1af0289d3d1b40787bb955e8603d96e96a6b14b225926e108fb"
+checksum = "377af281d8f23663862a7c84623bc5dcf7f8c44b13c7496a590bdc157f941a43"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1383,9 +1382,9 @@ dependencies = [
 
 [[package]]
 name = "itertools"
-version = "0.11.0"
+version = "0.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b1c173a5686ce8bfa551b3563d0c2170bf24ca44da99c7ca4bfdab5418c3fe57"
+checksum = "25db6b064527c5d482d0423354fcd07a89a2dfe07b67892e62411946db7f07b0"
 dependencies = [
  "either",
 ]
@@ -1427,7 +1426,7 @@ dependencies = [
 
 [[package]]
 name = "kcl-lib"
-version = "0.1.35"
+version = "0.1.36"
 dependencies = [
  "anyhow",
  "async-recursion",
@@ -1441,7 +1440,7 @@ dependencies = [
  "expectorate",
  "futures",
  "insta",
- "itertools 0.11.0",
+ "itertools 0.12.0",
  "js-sys",
  "kittycad",
  "lazy_static",
@@ -1477,9 +1476,9 @@ dependencies = [
 
 [[package]]
 name = "kittycad"
-version = "0.2.41"
+version = "0.2.42"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "874914cd40bfd43674406683bb3f0924d41780698a4ade96f2e180a73678bdd1"
+checksum = "6aa554d86b6dbbd976a659c912ae25ce817b4378eb12a5684907e263410f0a7b"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -1784,7 +1783,7 @@ checksum = "0ab1bc2a289d34bd04a330323ac98a1b4bc82c9d9fcb1e66b63caa84da26b575"
 [[package]]
 name = "openapitor"
 version = "0.0.9"
-source = "git+https://github.com/KittyCAD/kittycad.rs?branch=main#1b2562f4b3ecd26a3683c3fc48a0d33707097a36"
+source = "git+https://github.com/KittyCAD/kittycad.rs?branch=main#9caff1f4f00c64632ff5a226251e3dc68210b455"
 dependencies = [
  "Inflector",
  "anyhow",
@@ -1954,7 +1953,7 @@ dependencies = [
  "bincode",
  "either",
  "fnv",
- "itertools 0.11.0",
+ "itertools 0.10.5",
  "lazy_static",
  "nom",
  "quick-xml",
@@ -2521,9 +2520,9 @@ dependencies = [
 
 [[package]]
 name = "schemars"
-version = "0.8.15"
+version = "0.8.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1f7b0ce13155372a76ee2e1c5ffba1fe61ede73fbea5630d61eee6fac4929c0c"
+checksum = "45a28f4c49489add4ce10783f7911893516f15afe45d015608d41faca6bc4d29"
 dependencies = [
  "bigdecimal",
  "bytes",
@@ -2538,9 +2537,9 @@ dependencies = [
 
 [[package]]
 name = "schemars_derive"
-version = "0.8.15"
+version = "0.8.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e85e2a16b12bdb763244c69ab79363d71db2b4b918a2def53f80b02e0574b13c"
+checksum = "c767fd6fa65d9ccf9cf026122c1b555f2ef9a4f0cea69da4d7dbc3e258d30967"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -3548,9 +3547,9 @@ checksum = "711b9620af191e0cdc7468a8d14e709c3dcdb115b36f838e601583af800a370a"
 
 [[package]]
 name = "uuid"
-version = "1.5.0"
+version = "1.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "88ad59a7560b41a70d191093a945f0b87bc1deeda46fb237479708a1d6b6cdfc"
+checksum = "c58fe91d841bc04822c9801002db4ea904b9e4b8e6bbad25127b46eff8dc516b"
 dependencies = [
  "atomic",
  "getrandom",

src/wasm-lib/Cargo.toml

@@ -15,7 +15,7 @@ gloo-utils = "0.2.0"
 kcl-lib = { path = "kcl" }
 kittycad = { workspace = true }
 serde_json = "1.0.108"
-uuid = { version = "1.5.0", features = ["v4", "js", "serde"] }
+uuid = { version = "1.6.0", features = ["v4", "js", "serde"] }
 wasm-bindgen = "0.2.88"
 wasm-bindgen-futures = "0.4.38"
 
@@ -27,7 +27,7 @@ pretty_assertions = "1.4.0"
 reqwest = { version = "0.11.22", default-features = false }
 tokio = { version = "1.34.0", features = ["rt-multi-thread", "macros", "time"] }
 twenty-twenty = "0.6.1"
-uuid = { version = "1.5.0", features = ["v4", "js", "serde"] }
+uuid = { version = "1.6.0", features = ["v4", "js", "serde"] }
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 futures = "0.3.29"
@@ -57,7 +57,7 @@ members = [
 ]
 
 [workspace.dependencies]
-kittycad = { version = "0.2.41", default-features = false, features = ["js"] }
+kittycad = { version = "0.2.42", default-features = false, features = ["js"] }
 
 [[test]]
 name = "executor"

src/wasm-lib/kcl-macros/Cargo.toml

@@ -12,7 +12,7 @@ repository = "https://github.com/KittyCAD/modeling-app"
 proc-macro = true
 
 [dependencies]
-databake = "0.1.6"
+databake = "0.1.7"
 kcl-lib = { path = "../kcl" }
 proc-macro2 = "1"
 quote = "1"

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

@@ -1,3 +1,4 @@
+//! This crate contains macros for parsing KCL at Rust compile-time.
 use databake::*;
 use proc_macro::TokenStream;
 use quote::quote;

src/wasm-lib/kcl/Cargo.toml

@@ -1,11 +1,13 @@
 [package]
 name = "kcl-lib"
-description = "KittyCAD Language"
+description = "KittyCAD Language implementation and tools"
-version = "0.1.35"
+version = "0.1.36"
 edition = "2021"
 license = "MIT"
 repository = "https://github.com/KittyCAD/modeling-app"
 rust-version = "1.73"
+authors = ["Jess Frazelle", "Adam Chalmers", "KittyCAD, Inc"]
+keywords = ["kcl", "KittyCAD", "CAD"]
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
@@ -15,18 +17,18 @@ async-recursion = "1.0.5"
 async-trait = "0.1.73"
 clap = { version = "4.4.8", features = ["cargo", "derive", "env", "unicode"], optional = true }
 dashmap = "5.5.3"
-databake = { version = "0.1.6", features = ["derive"] }
+databake = { version = "0.1.7", features = ["derive"] }
 derive-docs = { version = "0.1.4" }
 #derive-docs = { path = "../derive-docs" }
 kittycad = { workspace = true }
 lazy_static = "1.4.0"
 parse-display = "0.8.2"
-schemars = { version = "0.8", features = ["impl_json_schema", "url", "uuid1"] }
+schemars = { version = "0.8.16", features = ["impl_json_schema", "url", "uuid1"] }
 serde = { version = "1.0.192", features = ["derive"] }
 serde_json = "1.0.108"
 thiserror = "1.0.50"
 ts-rs = { version = "7", package = "ts-rs-json-value", features = ["serde-json-impl", "schemars-impl", "uuid-impl"] }
-uuid = { version = "1.5.0", features = ["v4", "js", "serde"] }
+uuid = { version = "1.6.0", features = ["v4", "js", "serde"] }
 winnow = "0.5.18"
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
@@ -60,7 +62,7 @@ debug = true # Flamegraphs of benchmarks require accurate debug symbols
 criterion = "0.5.1"
 expectorate = "1.1.0"
 insta = { version = "1.34.0", features = ["json"] }
-itertools = "0.11.0"
+itertools = "0.12.0"
 pretty_assertions = "1.4.0"
 tokio = { version = "1.34.0", features = ["rt-multi-thread", "macros", "time"] }
 

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

@@ -221,11 +221,11 @@ impl Program {
             if let Some(Value::FunctionExpression(ref mut function_expression)) = &mut value {
                 // Check if the params to the function expression contain the position.
                 for param in &mut function_expression.params {
-                    let param_source_range: SourceRange = param.clone().into();
+                    let param_source_range: SourceRange = (&param.identifier).into();
                     if param_source_range.contains(pos) {
-                        let old_name = param.name.clone();
+                        let old_name = param.identifier.name.clone();
                         // Rename the param.
-                        param.rename(&old_name, new_name);
+                        param.identifier.rename(&old_name, new_name);
                         // Now rename all the identifiers in the rest of the program.
                         function_expression.body.rename_identifiers(&old_name, new_name);
                         return;
@@ -1014,7 +1014,11 @@ impl CallExpression {
                 // Add the arguments to the memory.
                 let mut fn_memory = memory.clone();
                 for (index, param) in function_expression.params.iter().enumerate() {
-                    fn_memory.add(&param.name, fn_args.get(index).unwrap().clone(), param.into())?;
+                    fn_memory.add(
+                        &param.identifier.name,
+                        fn_args.get(index).unwrap().clone(),
+                        param.identifier.clone().into(),
+                    )?;
                 }
 
                 // Call the stdlib function
@@ -1249,10 +1253,10 @@ impl VariableDeclaration {
                     symbol_kind = SymbolKind::FUNCTION;
                     let mut children = vec![];
                     for param in &function_expression.params {
-                        let param_source_range: SourceRange = param.into();
+                        let param_source_range: SourceRange = (&param.identifier).into();
                         #[allow(deprecated)]
                         children.push(DocumentSymbol {
-                            name: param.name.clone(),
+                            name: param.identifier.name.clone(),
                             detail: None,
                             kind: SymbolKind::VARIABLE,
                             range: param_source_range.to_lsp_range(code),
@@ -1442,7 +1446,7 @@ impl From<&Box<Literal>> for MemoryItem {
     }
 }
 
-#[derive(Debug, Clone, Deserialize, Serialize, PartialEq, ts_rs::TS, JsonSchema, Bake)]
+#[derive(Debug, Clone, Deserialize, Serialize, PartialEq, ts_rs::TS, JsonSchema, Bake, Eq)]
 #[databake(path = kcl_lib::ast::types)]
 #[ts(export)]
 #[serde(tag = "type")]
@@ -2621,6 +2625,18 @@ async fn execute_pipe_body(
     }
 }
 
+/// Parameter of a KCL function.
+#[derive(Debug, Clone, Deserialize, Serialize, PartialEq, ts_rs::TS, JsonSchema, Bake)]
+#[databake(path = kcl_lib::ast::types)]
+#[ts(export)]
+#[serde(tag = "type")]
+pub struct Parameter {
+    /// The parameter's label or name.
+    pub identifier: Identifier,
+    /// Is the parameter optional?
+    pub optional: bool,
+}
+
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq, ts_rs::TS, JsonSchema, Bake)]
 #[databake(path = kcl_lib::ast::types)]
 #[ts(export)]
@@ -2628,7 +2644,7 @@ async fn execute_pipe_body(
 pub struct FunctionExpression {
     pub start: usize,
     pub end: usize,
-    pub params: Vec<Identifier>,
+    pub params: Vec<Parameter>,
     pub body: Program,
 }
 
@@ -2654,7 +2670,7 @@ impl FunctionExpression {
             "({}) => {{\n{}{}\n}}",
             self.params
                 .iter()
-                .map(|param| param.name.clone())
+                .map(|param| param.identifier.name.clone())
                 .collect::<Vec<String>>()
                 .join(", "),
             options.get_indentation(indentation_level + 1),

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

@@ -908,9 +908,9 @@ pub async fn execute(
                                         // Add the arguments to the memory.
                                         for (index, param) in function_expression.params.iter().enumerate() {
                                             fn_memory.add(
-                                                &param.name,
+                                                &param.identifier.name,
                                                 args.get(index).unwrap().clone(),
-                                                param.into(),
+                                                (&param.identifier).into(),
                                             )?;
                                         }
 

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

@@ -1,3 +1,7 @@
+//! Rust support for KCL (aka the KittyCAD Language).
+//!
+//! KCL is written in Rust. This crate contains the compiler tooling (e.g. parser, lexer, code generation),
+//! the standard library implementation, a LSP implementation, generator for the docs, and more.
 #![recursion_limit = "1024"]
 
 pub mod ast;

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

@@ -12,7 +12,7 @@ use crate::{
         ArrayExpression, BinaryExpression, BinaryOperator, BinaryPart, BodyItem, CallExpression, CommentStyle,
         ExpressionStatement, FunctionExpression, Identifier, Literal, LiteralIdentifier, LiteralValue,
         MemberExpression, MemberObject, NonCodeMeta, NonCodeNode, NonCodeValue, ObjectExpression, ObjectProperty,
-        PipeExpression, PipeSubstitution, Program, ReturnStatement, UnaryExpression, UnaryOperator, Value,
+        Parameter, PipeExpression, PipeSubstitution, Program, ReturnStatement, UnaryExpression, UnaryOperator, Value,
         VariableDeclaration, VariableDeclarator, VariableKind,
     },
     errors::{KclError, KclErrorDetails},
@@ -1208,26 +1208,62 @@ fn arguments(i: TokenSlice) -> PResult<Vec<Value>> {
         .parse_next(i)
 }
 
-fn not_close_paren(i: TokenSlice) -> PResult<Token> {
+fn required_param(i: TokenSlice) -> PResult<Token> {
     any.verify(|token: &Token| !matches!(token.token_type, TokenType::Brace) || token.value != ")")
         .parse_next(i)
 }
 
+fn optional_param(i: TokenSlice) -> PResult<Token> {
+    let token = required_param.parse_next(i)?;
+    let _question_mark = one_of(TokenType::QuestionMark).parse_next(i)?;
+    Ok(token)
+}
+
 /// Parameters are declared in a function signature, and used within a function.
-fn parameters(i: TokenSlice) -> PResult<Vec<Identifier>> {
+fn parameters(i: TokenSlice) -> PResult<Vec<Parameter>> {
     // Get all tokens until the next ), because that ends the parameter list.
-    let candidates: Vec<Token> = separated(0.., not_close_paren, comma_sep)
+    let candidates: Vec<_> = separated(
-        .context(expected("function parameters"))
+        0..,
-        .parse_next(i)?;
+        alt((optional_param.map(|t| (t, true)), required_param.map(|t| (t, false)))),
+        comma_sep,
+    )
+    .context(expected("function parameters"))
+    .parse_next(i)?;
+
     // Make sure all those tokens are valid parameters.
-    let params = candidates
+    let params: Vec<Parameter> = candidates
         .into_iter()
-        .map(|token| Identifier::try_from(token).and_then(Identifier::into_valid_binding_name))
+        .map(|(token, optional)| {
+            let identifier = Identifier::try_from(token).and_then(Identifier::into_valid_binding_name)?;
+            Ok(Parameter { identifier, optional })
+        })
         .collect::<Result<_, _>>()
-        .map_err(|e| ErrMode::Backtrack(ContextError::from(e)))?;
+        .map_err(|e: KclError| ErrMode::Backtrack(ContextError::from(e)))?;
+
+    // Make sure optional parameters are last.
+    if let Err(e) = optional_after_required(&params) {
+        return Err(ErrMode::Cut(ContextError::from(e)));
+    }
     Ok(params)
 }
 
+fn optional_after_required(params: &[Parameter]) -> Result<(), KclError> {
+    let mut found_optional = false;
+    for p in params {
+        if p.optional {
+            found_optional = true;
+        }
+        if !p.optional && found_optional {
+            let e = KclError::Syntax(KclErrorDetails {
+                source_ranges: vec![(&p.identifier).into()],
+                message: "mandatory parameters must be declared before optional parameters".to_owned(),
+            });
+            return Err(e);
+        }
+    }
+    Ok(())
+}
+
 impl Identifier {
     fn into_valid_binding_name(self) -> Result<Identifier, KclError> {
         // Make sure they are not assigning a variable to a stdlib function.
@@ -1895,7 +1931,7 @@ const mySk1 = startSketchAt([0, 0])"#;
             let tokens = crate::token::lexer(input);
             let actual = parameters.parse(&tokens);
             assert!(actual.is_ok(), "could not parse test {i}");
-            let actual_ids: Vec<_> = actual.unwrap().into_iter().map(|id| id.name).collect();
+            let actual_ids: Vec<_> = actual.unwrap().into_iter().map(|p| p.identifier.name).collect();
             assert_eq!(actual_ids, expected);
         }
     }
@@ -2322,6 +2358,82 @@ e
         assert!(result.err().unwrap().to_string().contains("Unexpected token"));
     }
 
+    #[test]
+    fn test_optional_param_order() {
+        for (i, (params, expect_ok)) in [
+            (
+                vec![Parameter {
+                    identifier: Identifier {
+                        start: 0,
+                        end: 0,
+                        name: "a".to_owned(),
+                    },
+                    optional: true,
+                }],
+                true,
+            ),
+            (
+                vec![Parameter {
+                    identifier: Identifier {
+                        start: 0,
+                        end: 0,
+                        name: "a".to_owned(),
+                    },
+                    optional: false,
+                }],
+                true,
+            ),
+            (
+                vec![
+                    Parameter {
+                        identifier: Identifier {
+                            start: 0,
+                            end: 0,
+                            name: "a".to_owned(),
+                        },
+                        optional: false,
+                    },
+                    Parameter {
+                        identifier: Identifier {
+                            start: 0,
+                            end: 0,
+                            name: "b".to_owned(),
+                        },
+                        optional: true,
+                    },
+                ],
+                true,
+            ),
+            (
+                vec![
+                    Parameter {
+                        identifier: Identifier {
+                            start: 0,
+                            end: 0,
+                            name: "a".to_owned(),
+                        },
+                        optional: true,
+                    },
+                    Parameter {
+                        identifier: Identifier {
+                            start: 0,
+                            end: 0,
+                            name: "b".to_owned(),
+                        },
+                        optional: false,
+                    },
+                ],
+                false,
+            ),
+        ]
+        .into_iter()
+        .enumerate()
+        {
+            let actual = optional_after_required(&params);
+            assert_eq!(actual.is_ok(), expect_ok, "failed test {i}");
+        }
+    }
+
     #[test]
     fn test_parse_expand_array() {
         let code = "const myArray = [0..10]";
@@ -2801,4 +2913,5 @@ mod snapshot_tests {
     snapshot_test!(ar, r#"5 + "a""#);
     snapshot_test!(at, "line([0, l], %)");
     snapshot_test!(au, include_str!("../../../tests/executor/inputs/cylinder.kcl"));
+    snapshot_test!(av, "fn f = (angle?) => { return default(angle, 360) }");
 }

src/wasm-lib/kcl/src/parser/snapshots/kcl_lib__parser__parser_impl__snapshot_tests__ae.snap

@@ -29,10 +29,13 @@ expression: actual
             "end": 49,
             "params": [
               {
-                "type": "Identifier",
+                "identifier": {
-                "start": 12,
+                  "type": "Identifier",
-                "end": 17,
+                  "start": 12,
-                "name": "param"
+                  "end": 17,
+                  "name": "param"
+                },
+                "optional": false
               }
             ],
             "body": {

src/wasm-lib/kcl/src/parser/snapshots/kcl_lib__parser__parser_impl__snapshot_tests__av.snap

@@ -0,0 +1,97 @@
+---
+source: kcl/src/parser/parser_impl.rs
+expression: actual
+---
+{
+  "start": 0,
+  "end": 49,
+  "body": [
+    {
+      "type": "VariableDeclaration",
+      "type": "VariableDeclaration",
+      "start": 0,
+      "end": 49,
+      "declarations": [
+        {
+          "type": "VariableDeclarator",
+          "start": 3,
+          "end": 49,
+          "id": {
+            "type": "Identifier",
+            "start": 3,
+            "end": 4,
+            "name": "f"
+          },
+          "init": {
+            "type": "FunctionExpression",
+            "type": "FunctionExpression",
+            "start": 7,
+            "end": 49,
+            "params": [
+              {
+                "identifier": {
+                  "type": "Identifier",
+                  "start": 8,
+                  "end": 13,
+                  "name": "angle"
+                },
+                "optional": true
+              }
+            ],
+            "body": {
+              "start": 19,
+              "end": 49,
+              "body": [
+                {
+                  "type": "ReturnStatement",
+                  "type": "ReturnStatement",
+                  "start": 21,
+                  "end": 47,
+                  "argument": {
+                    "type": "CallExpression",
+                    "type": "CallExpression",
+                    "start": 28,
+                    "end": 47,
+                    "callee": {
+                      "type": "Identifier",
+                      "start": 28,
+                      "end": 35,
+                      "name": "default"
+                    },
+                    "arguments": [
+                      {
+                        "type": "Identifier",
+                        "type": "Identifier",
+                        "start": 36,
+                        "end": 41,
+                        "name": "angle"
+                      },
+                      {
+                        "type": "Literal",
+                        "type": "Literal",
+                        "start": 43,
+                        "end": 46,
+                        "value": 360,
+                        "raw": "360"
+                      }
+                    ],
+                    "optional": false
+                  }
+                }
+              ],
+              "nonCodeMeta": {
+                "nonCodeNodes": {},
+                "start": []
+              }
+            }
+          }
+        }
+      ],
+      "kind": "fn"
+    }
+  ],
+  "nonCodeMeta": {
+    "nonCodeNodes": {},
+    "start": []
+  }
+}

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

@@ -20,17 +20,12 @@ use crate::{
 /// Data to draw a line to a point.
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq, ts_rs::TS, JsonSchema)]
 #[ts(export)]
-#[serde(rename_all = "camelCase", untagged)]
+#[serde(rename_all = "camelCase")]
-pub enum LineToData {
+pub struct LineToData {
-    /// A point with a tag.
+    /// The to point.
-    PointWithTag {
+    to: [f64; 2],
-        /// The to point.
+    /// The tag.
-        to: [f64; 2],
+    tag: Option<String>,
-        /// The tag.
-        tag: String,
-    },
-    /// A point.
-    Point([f64; 2]),
 }
 
 /// Draw a line to a point.
@@ -51,10 +46,8 @@ async fn inner_line_to(
     args: Args,
 ) -> Result<Box<SketchGroup>, KclError> {
     let from = sketch_group.get_coords_from_paths()?;
-    let to = match data {
+    let to = data.to;
-        LineToData::PointWithTag { to, .. } => to,
+    let name = data.tag.unwrap_or_default();
-        LineToData::Point(to) => to,
-    };
 
     let id = uuid::Uuid::new_v4();
 
@@ -63,11 +56,7 @@ async fn inner_line_to(
         ModelingCmd::ExtendPath {
             path: sketch_group.id,
             segment: kittycad::types::PathSegment::Line {
-                end: Point3D {
+                end: point3d(to),
-                    x: to[0],
-                    y: to[1],
-                    z: 0.0,
-                },
                 relative: false,
             },
         },
@@ -78,11 +67,7 @@ async fn inner_line_to(
         base: BasePath {
             from: from.into(),
             to,
-            name: if let LineToData::PointWithTag { tag, .. } = data {
+            name,
-                tag.to_string()
-            } else {
-                "".to_string()
-            },
             geo_meta: GeoMeta {
                 id,
                 metadata: args.source_range.into(),
@@ -99,17 +84,12 @@ async fn inner_line_to(
 /// Data to draw a line to a point on an axis.
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq, ts_rs::TS, JsonSchema)]
 #[ts(export)]
-#[serde(rename_all = "camelCase", untagged)]
+#[serde(rename_all = "camelCase")]
-pub enum AxisLineToData {
+pub struct AxisLineToData {
-    /// A point with a tag.
+    /// The to point.
-    PointWithTag {
+    to: f64,
-        /// The to point.
+    /// The tag.
-        to: f64,
+    tag: Option<String>,
-        /// The tag.
-        tag: String,
-    },
-    /// A point.
-    Point(f64),
 }
 
 /// Draw a line to a point on the x-axis.
@@ -131,9 +111,9 @@ async fn inner_x_line_to(
 ) -> Result<Box<SketchGroup>, KclError> {
     let from = sketch_group.get_coords_from_paths()?;
 
-    let line_to_data = match data {
+    let line_to_data = LineToData {
-        AxisLineToData::PointWithTag { to, tag } => LineToData::PointWithTag { to: [to, from.y], tag },
+        to: [data.to, from.y],
-        AxisLineToData::Point(data) => LineToData::Point([data, from.y]),
+        tag: data.tag,
     };
 
     let new_sketch_group = inner_line_to(line_to_data, sketch_group, args).await?;
@@ -160,9 +140,9 @@ async fn inner_y_line_to(
 ) -> Result<Box<SketchGroup>, KclError> {
     let from = sketch_group.get_coords_from_paths()?;
 
-    let line_to_data = match data {
+    let line_to_data = LineToData {
-        AxisLineToData::PointWithTag { to, tag } => LineToData::PointWithTag { to: [from.x, to], tag },
+        to: [from.x, data.to],
-        AxisLineToData::Point(data) => LineToData::Point([from.x, data]),
+        tag: data.tag,
     };
 
     let new_sketch_group = inner_line_to(line_to_data, sketch_group, args).await?;
@@ -172,17 +152,12 @@ async fn inner_y_line_to(
 /// Data to draw a line.
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq, ts_rs::TS, JsonSchema)]
 #[ts(export)]
-#[serde(rename_all = "camelCase", untagged)]
+#[serde(rename_all = "camelCase")]
-pub enum LineData {
+pub struct LineData {
-    /// A point with a tag.
+    /// The to point.
-    PointWithTag {
+    to: [f64; 2],
-        /// The to point.
+    /// The tag.
-        to: [f64; 2],
+    tag: Option<String>,
-        /// The tag.
-        tag: String,
-    },
-    /// A point.
-    Point([f64; 2]),
 }
 
 /// Draw a line.
@@ -199,10 +174,7 @@ pub async fn line(args: Args) -> Result<MemoryItem, KclError> {
 }]
 async fn inner_line(data: LineData, sketch_group: Box<SketchGroup>, args: Args) -> Result<Box<SketchGroup>, KclError> {
     let from = sketch_group.get_coords_from_paths()?;
-    let inner_args = match &data {
+    let inner_args = data.to;
-        LineData::PointWithTag { to, .. } => *to,
-        LineData::Point(to) => *to,
-    };
 
     let delta = inner_args;
     let to = [from.x + inner_args[0], from.y + inner_args[1]];
@@ -214,11 +186,7 @@ async fn inner_line(data: LineData, sketch_group: Box<SketchGroup>, args: Args)
         ModelingCmd::ExtendPath {
             path: sketch_group.id,
             segment: kittycad::types::PathSegment::Line {
-                end: Point3D {
+                end: point3d(delta),
-                    x: delta[0],
-                    y: delta[1],
-                    z: 0.0,
-                },
                 relative: true,
             },
         },
@@ -229,11 +197,7 @@ async fn inner_line(data: LineData, sketch_group: Box<SketchGroup>, args: Args)
         base: BasePath {
             from: from.into(),
             to,
-            name: if let LineData::PointWithTag { tag, .. } = data {
+            name: data.tag.unwrap_or_default(),
-                tag.to_string()
-            } else {
-                "".to_string()
-            },
             geo_meta: GeoMeta {
                 id,
                 metadata: args.source_range.into(),
@@ -250,17 +214,12 @@ async fn inner_line(data: LineData, sketch_group: Box<SketchGroup>, args: Args)
 /// Data to draw a line on an axis.
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq, ts_rs::TS, JsonSchema)]
 #[ts(export)]
-#[serde(rename_all = "camelCase", untagged)]
+#[serde(rename_all = "camelCase")]
-pub enum AxisLineData {
+pub struct AxisLineData {
-    /// The length with a tag.
+    /// The length of the line.
-    LengthWithTag {
+    length: f64,
-        /// The length of the line.
+    /// The tag.
-        length: f64,
+    tag: Option<String>,
-        /// The tag.
-        tag: String,
-    },
-    /// The length.
-    Length(f64),
 }
 
 /// Draw a line on the x-axis.
@@ -280,9 +239,9 @@ async fn inner_x_line(
     sketch_group: Box<SketchGroup>,
     args: Args,
 ) -> Result<Box<SketchGroup>, KclError> {
-    let line_data = match data {
+    let line_data = LineData {
-        AxisLineData::LengthWithTag { length, tag } => LineData::PointWithTag { to: [length, 0.0], tag },
+        to: [data.length, 0.0],
-        AxisLineData::Length(length) => LineData::Point([length, 0.0]),
+        tag: data.tag,
     };
 
     let new_sketch_group = inner_line(line_data, sketch_group, args).await?;
@@ -306,9 +265,9 @@ async fn inner_y_line(
     sketch_group: Box<SketchGroup>,
     args: Args,
 ) -> Result<Box<SketchGroup>, KclError> {
-    let line_data = match data {
+    let line_data = LineData {
-        AxisLineData::LengthWithTag { length, tag } => LineData::PointWithTag { to: [0.0, length], tag },
+        to: [0.0, data.length],
-        AxisLineData::Length(length) => LineData::Point([0.0, length]),
+        tag: data.tag,
     };
 
     let new_sketch_group = inner_line(line_data, sketch_group, args).await?;
@@ -318,28 +277,19 @@ async fn inner_y_line(
 /// Data to draw an angled line.
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq, ts_rs::TS, JsonSchema)]
 #[ts(export)]
-#[serde(rename_all = "camelCase", untagged)]
+#[serde(rename_all = "camelCase")]
-pub enum AngledLineData {
+pub struct AngledLineData {
-    /// An angle and length with a tag.
+    /// The angle of the line.
-    AngleWithTag {
+    angle: f64,
-        /// The angle of the line.
+    /// The length of the line.
-        angle: f64,
+    length: f64,
-        /// The length of the line.
+    /// The tag.
-        length: f64,
+    tag: Option<String>,
-        /// The tag.
-        tag: String,
-    },
-    /// An angle and length.
-    AngleAndLength([f64; 2]),
 }
 
 impl AngledLineData {
     pub fn into_inner_line(self, to: [f64; 2]) -> LineData {
-        if let AngledLineData::AngleWithTag { tag, .. } = self {
+        LineData { to, tag: self.tag }
-            LineData::PointWithTag { to, tag }
-        } else {
-            LineData::Point(to)
-        }
     }
 }
 
@@ -361,10 +311,7 @@ async fn inner_angled_line(
     args: Args,
 ) -> Result<Box<SketchGroup>, KclError> {
     let from = sketch_group.get_coords_from_paths()?;
-    let (angle, length) = match &data {
+    let AngledLineData { angle, length, tag } = data;
-        AngledLineData::AngleWithTag { angle, length, .. } => (*angle, *length),
-        AngledLineData::AngleAndLength(angle_and_length) => (angle_and_length[0], angle_and_length[1]),
-    };
 
     //double check me on this one - mike
     let delta: [f64; 2] = [
@@ -381,11 +328,7 @@ async fn inner_angled_line(
         base: BasePath {
             from: from.into(),
             to,
-            name: if let AngledLineData::AngleWithTag { tag, .. } = data {
+            name: tag.unwrap_or_default(),
-                tag.to_string()
-            } else {
-                "".to_string()
-            },
             geo_meta: GeoMeta {
                 id,
                 metadata: args.source_range.into(),
@@ -398,11 +341,7 @@ async fn inner_angled_line(
         ModelingCmd::ExtendPath {
             path: sketch_group.id,
             segment: kittycad::types::PathSegment::Line {
-                end: Point3D {
+                end: point3d(delta),
-                    x: delta[0],
-                    y: delta[1],
-                    z: 0.0,
-                },
                 relative,
             },
         },
@@ -431,12 +370,7 @@ async fn inner_angled_line_of_x_length(
     sketch_group: Box<SketchGroup>,
     args: Args,
 ) -> Result<Box<SketchGroup>, KclError> {
-    let (angle, length) = match &data {
+    let to = get_y_component(Angle::from_degrees(data.angle), data.length);
-        AngledLineData::AngleWithTag { angle, length, .. } => (*angle, *length),
-        AngledLineData::AngleAndLength(angle_and_length) => (angle_and_length[0], angle_and_length[1]),
-    };
-
-    let to = get_y_component(Angle::from_degrees(angle), length);
 
     let new_sketch_group = inner_line(data.into_inner_line(to.into()), sketch_group, args).await?;
 
@@ -446,28 +380,20 @@ async fn inner_angled_line_of_x_length(
 /// Data to draw an angled line to a point.
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq, ts_rs::TS, JsonSchema)]
 #[ts(export)]
-#[serde(rename_all = "camelCase", untagged)]
+#[serde(rename_all = "camelCase")]
-pub enum AngledLineToData {
+pub struct AngledLineToData {
-    /// An angle and point with a tag.
+    /// The angle of the line.
-    AngleWithTag {
+    angle: f64,
-        /// The angle of the line.
+    /// The point to draw to.
-        angle: f64,
+    to: f64,
-        /// The point to draw to.
+    /// The tag.
-        to: f64,
+    tag: Option<String>,
-        /// The tag.
-        tag: String,
-    },
-    /// An angle and point to draw to.
-    AngleAndPoint([f64; 2]),
 }
 
 impl AngledLineToData {
     pub fn into_inner_line(self, x_to: f64, y_to: f64) -> LineToData {
-        if let AngledLineToData::AngleWithTag { tag, .. } = self {
+        let tag = self.tag;
-            LineToData::PointWithTag { to: [x_to, y_to], tag }
+        LineToData { to: [x_to, y_to], tag }
-        } else {
-            LineToData::Point([x_to, y_to])
-        }
     }
 }
 
@@ -489,10 +415,7 @@ async fn inner_angled_line_to_x(
     args: Args,
 ) -> Result<Box<SketchGroup>, KclError> {
     let from = sketch_group.get_coords_from_paths()?;
-    let (angle, x_to) = match &data {
+    let (angle, x_to) = (data.angle, data.to);
-        AngledLineToData::AngleWithTag { angle, to, .. } => (*angle, *to),
-        AngledLineToData::AngleAndPoint(angle_and_to) => (angle_and_to[0], angle_and_to[1]),
-    };
 
     let x_component = x_to - from.x;
     let y_component = x_component * f64::tan(angle.to_radians());
@@ -520,10 +443,7 @@ async fn inner_angled_line_of_y_length(
     sketch_group: Box<SketchGroup>,
     args: Args,
 ) -> Result<Box<SketchGroup>, KclError> {
-    let (angle, length) = match &data {
+    let (angle, length) = (data.angle, data.length);
-        AngledLineData::AngleWithTag { angle, length, .. } => (*angle, *length),
-        AngledLineData::AngleAndLength(angle_and_length) => (angle_and_length[0], angle_and_length[1]),
-    };
 
     let to = get_x_component(Angle::from_degrees(angle), length);
 
@@ -550,10 +470,7 @@ async fn inner_angled_line_to_y(
     args: Args,
 ) -> Result<Box<SketchGroup>, KclError> {
     let from = sketch_group.get_coords_from_paths()?;
-    let (angle, y_to) = match &data {
+    let (angle, y_to) = (data.angle, data.to);
-        AngledLineToData::AngleWithTag { angle, to, .. } => (*angle, *to),
-        AngledLineToData::AngleAndPoint(angle_and_to) => (angle_and_to[0], angle_and_to[1]),
-    };
 
     let y_component = y_to - from.y;
     let x_component = y_component / f64::tan(angle.to_radians());
@@ -616,10 +533,9 @@ async fn inner_angled_line_that_intersects(
         from,
     );
 
-    let line_to_data = if let Some(tag) = data.tag {
+    let line_to_data = LineToData {
-        LineToData::PointWithTag { to: to.into(), tag }
+        to: to.into(),
-    } else {
+        tag: data.tag,
-        LineToData::Point(to.into())
     };
 
     let new_sketch_group = inner_line_to(line_to_data, sketch_group, args).await?;
@@ -830,10 +746,7 @@ pub async fn start_profile_at(args: Args) -> Result<MemoryItem, KclError> {
     name = "startProfileAt",
 }]
 async fn inner_start_profile_at(data: LineData, plane: Box<Plane>, args: Args) -> Result<Box<SketchGroup>, KclError> {
-    let to = match &data {
+    let to = data.to;
-        LineData::PointWithTag { to, .. } => *to,
-        LineData::Point(to) => *to,
-    };
 
     let id = uuid::Uuid::new_v4();
     let path_id = uuid::Uuid::new_v4();
@@ -843,11 +756,7 @@ async fn inner_start_profile_at(data: LineData, plane: Box<Plane>, args: Args) -
         id,
         ModelingCmd::MovePathPen {
             path: path_id,
-            to: Point3D {
+            to: point3d(to),
-                x: to[0],
-                y: to[1],
-                z: 0.0,
-            },
         },
     )
     .await?;
@@ -855,11 +764,7 @@ async fn inner_start_profile_at(data: LineData, plane: Box<Plane>, args: Args) -
     let current_path = BasePath {
         from: to,
         to,
-        name: if let LineData::PointWithTag { tag, .. } = data {
+        name: data.tag.unwrap_or_default(),
-            tag.to_string()
-        } else {
-            "".to_string()
-        },
         geo_meta: GeoMeta {
             id,
             metadata: args.source_range.into(),
@@ -943,16 +848,7 @@ pub enum ArcData {
         /// The radius.
         radius: f64,
         /// The tag.
-        tag: String,
+        tag: Option<String>,
-    },
-    /// Angles and radius.
-    AnglesAndRadius {
-        /// The start angle.
-        angle_start: f64,
-        /// The end angle.
-        angle_end: f64,
-        /// The radius.
-        radius: f64,
     },
     /// Center, to and radius with a tag.
     CenterToRadiusWithTag {
@@ -963,16 +859,7 @@ pub enum ArcData {
         /// The radius.
         radius: f64,
         /// The tag.
-        tag: String,
+        tag: Option<String>,
-    },
-    /// Center, to and radius.
-    CenterToRadius {
-        /// The center.
-        center: [f64; 2],
-        /// The to point.
-        to: [f64; 2],
-        /// The radius.
-        radius: f64,
     },
 }
 
@@ -1003,24 +890,10 @@ async fn inner_arc(data: ArcData, sketch_group: Box<SketchGroup>, args: Args) ->
             let (center, end) = arc_center_and_end(from, a_start, a_end, *radius);
             (center, a_start, a_end, *radius, end)
         }
-        ArcData::AnglesAndRadius {
-            angle_start,
-            angle_end,
-            radius,
-        } => {
-            let a_start = Angle::from_degrees(*angle_start);
-            let a_end = Angle::from_degrees(*angle_end);
-            let (center, end) = arc_center_and_end(from, a_start, a_end, *radius);
-            (center, a_start, a_end, *radius, end)
-        }
         ArcData::CenterToRadiusWithTag { center, to, radius, .. } => {
             let (angle_start, angle_end) = arc_angles(from, center.into(), to.into(), *radius, args.source_range)?;
             (center.into(), angle_start, angle_end, *radius, to.into())
         }
-        ArcData::CenterToRadius { center, to, radius } => {
-            let (angle_start, angle_end) = arc_angles(from, center.into(), to.into(), *radius, args.source_range)?;
-            (center.into(), angle_start, angle_end, *radius, to.into())
-        }
     };
 
     let id = uuid::Uuid::new_v4();
@@ -1047,10 +920,8 @@ async fn inner_arc(data: ArcData, sketch_group: Box<SketchGroup>, args: Args) ->
             from: from.into(),
             to: end.into(),
             name: match data {
-                ArcData::AnglesAndRadiusWithTag { tag, .. } => tag.to_string(),
+                ArcData::AnglesAndRadiusWithTag { tag, .. } => tag.unwrap_or_default(),
-                ArcData::AnglesAndRadius { .. } => "".to_string(),
+                ArcData::CenterToRadiusWithTag { tag, .. } => tag.unwrap_or_default(),
-                ArcData::CenterToRadiusWithTag { tag, .. } => tag.to_string(),
-                ArcData::CenterToRadius { .. } => "".to_string(),
             },
             geo_meta: GeoMeta {
                 id,
@@ -1082,10 +953,8 @@ pub enum TangentialArcData {
         /// Where the arc should end. Must lie in the same plane as the current path pen position. Must not be colinear with current path pen position.
         to: [f64; 2],
         /// The tag.
-        tag: String,
+        tag: Option<String>,
     },
-    /// A point where the arc should end. Must lie in the same plane as the current path pen position. Must not be colinear with current path pen position.
-    Point([f64; 2]),
 }
 
 /// Draw a tangential arc.
@@ -1135,11 +1004,6 @@ async fn inner_tangential_arc(
         TangentialArcData::PointWithTag { to, .. } => {
             args.send_modeling_cmd(id, tan_arc_to(&sketch_group, to)).await?;
 
-            *to
-        }
-        TangentialArcData::Point(to) => {
-            args.send_modeling_cmd(id, tan_arc_to(&sketch_group, to)).await?;
-
             *to
         }
     };
@@ -1169,11 +1033,7 @@ fn tan_arc_to(sketch_group: &SketchGroup, to: &[f64; 2]) -> ModelingCmd {
         path: sketch_group.id,
         segment: kittycad::types::PathSegment::TangentialArcTo {
             angle_snap_increment: None,
-            to: Point3D {
+            to: point3d(*to),
-                x: to[0],
-                y: to[1],
-                z: 0.0,
-            },
         },
     }
 }
@@ -1181,17 +1041,12 @@ fn tan_arc_to(sketch_group: &SketchGroup, to: &[f64; 2]) -> ModelingCmd {
 /// Data to draw a tangential arc to a specific point.
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq, JsonSchema, ts_rs::TS)]
 #[ts(export)]
-#[serde(rename_all = "camelCase", untagged)]
+#[serde(rename_all = "camelCase")]
-pub enum TangentialArcToData {
+pub struct TangentialArcToData {
-    /// A point with a tag.
+    /// Where the arc should end. Must lie in the same plane as the current path pen position. Must not be colinear with current path pen position.
-    PointWithTag {
+    to: [f64; 2],
-        /// Where the arc should end. Must lie in the same plane as the current path pen position. Must not be colinear with current path pen position.
+    /// The tag.
-        to: [f64; 2],
+    tag: Option<String>,
-        /// The tag.
-        tag: String,
-    },
-    /// A point where the arc should end. Must lie in the same plane as the current path pen position. Must not be colinear with current path pen position.
-    Point([f64; 2]),
 }
 
 /// Draw a tangential arc to a specific point.
@@ -1212,10 +1067,8 @@ async fn inner_tangential_arc_to(
     args: Args,
 ) -> Result<Box<SketchGroup>, KclError> {
     let from: Point2d = sketch_group.get_coords_from_paths()?;
-    let to = match &data {
+    let to = data.to;
-        TangentialArcToData::PointWithTag { to, .. } => to,
+    let name = data.tag.unwrap_or_default().to_owned();
-        TangentialArcToData::Point(to) => to,
-    };
 
     let delta = [to[0] - from.x, to[1] - from.y];
     let id = uuid::Uuid::new_v4();
@@ -1224,12 +1077,8 @@ async fn inner_tangential_arc_to(
     let current_path = Path::ToPoint {
         base: BasePath {
             from: from.into(),
-            to: *to,
+            to,
-            name: if let TangentialArcToData::PointWithTag { tag, .. } = data {
+            name,
-                tag.to_string()
-            } else {
-                "".to_string()
-            },
             geo_meta: GeoMeta {
                 id,
                 metadata: args.source_range.into(),
@@ -1246,28 +1095,16 @@ async fn inner_tangential_arc_to(
 /// Data to draw a bezier curve.
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq, ts_rs::TS, JsonSchema)]
 #[ts(export)]
-#[serde(rename_all = "camelCase", untagged)]
+#[serde(rename_all = "camelCase")]
-pub enum BezierData {
+pub struct BezierData {
-    /// Points with a tag.
+    /// The to point.
-    PointsWithTag {
+    to: [f64; 2],
-        /// The to point.
+    /// The first control point.
-        to: [f64; 2],
+    control1: [f64; 2],
-        /// The first control point.
+    /// The second control point.
-        control1: [f64; 2],
+    control2: [f64; 2],
-        /// The second control point.
+    /// The tag.
-        control2: [f64; 2],
+    tag: Option<String>,
-        /// The tag.
-        tag: String,
-    },
-    /// Points.
-    Points {
-        /// The to point.
-        to: [f64; 2],
-        /// The first control point.
-        control1: [f64; 2],
-        /// The second control point.
-        control2: [f64; 2],
-    },
 }
 
 /// Draw a bezier curve.
@@ -1289,12 +1126,13 @@ async fn inner_bezier_curve(
 ) -> Result<Box<SketchGroup>, KclError> {
     let from = sketch_group.get_coords_from_paths()?;
 
-    let (to, control1, control2) = match &data {
+    let BezierData {
-        BezierData::PointsWithTag {
+        to,
-            to, control1, control2, ..
+        control1,
-        } => (to, control1, control2),
+        control2,
-        BezierData::Points { to, control1, control2 } => (to, control1, control2),
+        tag,
-    };
+    } = data;
+    let name = tag.unwrap_or_default();
 
     let relative = true;
     let delta = to;
@@ -1307,21 +1145,9 @@ async fn inner_bezier_curve(
         ModelingCmd::ExtendPath {
             path: sketch_group.id,
             segment: kittycad::types::PathSegment::Bezier {
-                control1: Point3D {
+                control1: point3d(control1),
-                    x: control1[0],
+                control2: point3d(control2),
-                    y: control1[1],
+                end: point3d(delta),
-                    z: 0.0,
-                },
-                control2: Point3D {
-                    x: control2[0],
-                    y: control2[1],
-                    z: 0.0,
-                },
-                end: Point3D {
-                    x: delta[0],
-                    y: delta[1],
-                    z: 0.0,
-                },
                 relative,
             },
         },
@@ -1332,11 +1158,7 @@ async fn inner_bezier_curve(
         base: BasePath {
             from: from.into(),
             to,
-            name: if let BezierData::PointsWithTag { tag, .. } = data {
+            name,
-                tag.to_string()
-            } else {
-                "".to_string()
-            },
             geo_meta: GeoMeta {
                 id,
                 metadata: args.source_range.into(),
@@ -1394,6 +1216,10 @@ async fn inner_hole(
     Ok(sketch_group)
 }
 
+fn point3d([x, y]: [f64; 2]) -> Point3D {
+    Point3D { x, y, z: 0.0 }
+}
+
 #[cfg(test)]
 mod tests {
 
@@ -1403,21 +1229,30 @@ mod tests {
 
     #[test]
     fn test_deserialize_line_data() {
-        let data = LineData::Point([0.0, 1.0]);
+        let data = LineData {
+            to: [0.0, 1.0],
+            tag: None,
+        };
         let mut str_json = serde_json::to_string(&data).unwrap();
         assert_eq!(str_json, "[0.0,1.0]");
 
         str_json = "[0, 1]".to_string();
         let data: LineData = serde_json::from_str(&str_json).unwrap();
-        assert_eq!(data, LineData::Point([0.0, 1.0]));
+        assert_eq!(
+            data,
+            LineData {
+                to: [0.0, 1.0],
+                tag: None
+            }
+        );
 
         str_json = "{ \"to\": [0.0, 1.0], \"tag\": \"thing\" }".to_string();
         let data: LineData = serde_json::from_str(&str_json).unwrap();
         assert_eq!(
             data,
-            LineData::PointWithTag {
+            LineData {
                 to: [0.0, 1.0],
-                tag: "thing".to_string()
+                tag: Some("thing".to_string()),
             }
         );
     }

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

@@ -47,6 +47,8 @@ pub enum TokenType {
     Function,
     /// Unknown lexemes.
     Unknown,
+    /// The ? symbol, used for optional values.
+    QuestionMark,
 }
 
 /// Most KCL tokens correspond to LSP semantic tokens (but not all).
@@ -58,6 +60,7 @@ impl TryFrom<TokenType> for SemanticTokenType {
             TokenType::Word => Self::VARIABLE,
             TokenType::Keyword => Self::KEYWORD,
             TokenType::Operator => Self::OPERATOR,
+            TokenType::QuestionMark => Self::OPERATOR,
             TokenType::String => Self::STRING,
             TokenType::LineComment => Self::COMMENT,
             TokenType::BlockComment => Self::COMMENT,

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

@@ -21,6 +21,7 @@ pub fn token(i: &mut Located<&str>) -> PResult<Token> {
         '{' | '(' | '[' => brace_start,
         '}' | ')' | ']' => brace_end,
         ',' => comma,
+        '?' => question_mark,
         '0'..='9' => number,
         ':' => colon,
         '.' => alt((number, double_period, period)),
@@ -108,6 +109,11 @@ fn comma(i: &mut Located<&str>) -> PResult<Token> {
     Ok(Token::from_range(range, TokenType::Comma, value.to_string()))
 }
 
+fn question_mark(i: &mut Located<&str>) -> PResult<Token> {
+    let (value, range) = '?'.with_span().parse_next(i)?;
+    Ok(Token::from_range(range, TokenType::QuestionMark, value.to_string()))
+}
+
 fn colon(i: &mut Located<&str>) -> PResult<Token> {
     let (value, range) = ':'.with_span().parse_next(i)?;
     Ok(Token::from_range(range, TokenType::Colon, value.to_string()))

yarn.lock

@@ -2525,16 +2525,17 @@
     "@types/babel__core" "^7.20.3"
     react-refresh "^0.14.0"
 
-"@vitest/coverage-istanbul@^0.34.1":
+"@vitest/coverage-istanbul@^0.34.6":
-  version "0.34.1"
+  version "0.34.6"
-  resolved "https://registry.yarnpkg.com/@vitest/coverage-istanbul/-/coverage-istanbul-0.34.1.tgz#a3cf36630c95b090457138b0706133b69ab59189"
+  resolved "https://registry.yarnpkg.com/@vitest/coverage-istanbul/-/coverage-istanbul-0.34.6.tgz#4fc91eac4d7cfc5b91850e9f82bcb986990b79a4"
-  integrity sha512-5GprlyY2t1g6+RrssWcN/w5RnZV3qIOM0eoaSDJw3jXbHpBpMvAfTg791zXo7PIqNYs5ORUqBWXIIU0gyAfZxA==
+  integrity sha512-5KaBNZPDSk2ybavC3rZ1pWGniw7sJ5usuwVGRUYzJwiBfWvnLpuUer7bjw7qUCRGdKJXrBgb/Dsgif9rkwMX/A==
   dependencies:
     istanbul-lib-coverage "^3.2.0"
     istanbul-lib-instrument "^6.0.0"
     istanbul-lib-report "^3.0.1"
     istanbul-lib-source-maps "^4.0.1"
     istanbul-reports "^3.1.5"
+    picocolors "^1.0.0"
     test-exclude "^6.0.0"
 
 "@vitest/expect@0.34.6":