Doc comments on parameters

Signed-off-by: Nick Cameron <nrc@ncameron.org>

rust/kcl-lib/src/docs/kcl_doc.rs

@@ -9,7 +9,7 @@ use tower_lsp::lsp_types::{
 use crate::{
     execution::annotations,
     parsing::{
-        ast::types::{Annotation, Node, NonCodeNode, PrimitiveType, Type, VariableKind},
+        ast::types::{Annotation, Node, PrimitiveType, Type, VariableKind},
         token::NumericSuffix,
     },
     ModuleId,
@@ -59,7 +59,6 @@ impl CollectionVisitor {
                         format!("std::{}::", self.name)
                     };
                     let mut dd = match var.kind {
-                        // TODO metadata for args
                         VariableKind::Fn => DocData::Fn(FnData::from_ast(var, qual_name)),
                         VariableKind::Const => DocData::Const(ConstData::from_ast(var, qual_name)),
                     };
@@ -494,7 +493,7 @@ pub struct ArgData {
     /// If the argument is required.
     pub kind: ArgKind,
     /// Additional information that could be used instead of the type's description.
-    /// This is helpful if the type is really basic, like "u32" -- that won't tell the user much about
+    /// This is helpful if the type is really basic, like "number" -- that won't tell the user much about
     /// how this argument is meant to be used.
     pub docs: Option<String>,
 }
@@ -509,21 +508,19 @@ pub enum ArgKind {
 
 impl ArgData {
     fn from_ast(arg: &crate::parsing::ast::types::Parameter) -> Self {
-        ArgData {
+        let mut result = ArgData {
             name: arg.identifier.name.clone(),
             ty: arg.type_.as_ref().map(|t| t.to_string()),
-            // Doc comments are not yet supported on parameters.
             docs: None,
             kind: if arg.labeled {
                 ArgKind::Labelled(arg.optional())
             } else {
                 ArgKind::Special
             },
-        }
-    }
+        };
 
-    fn _with_meta(&mut self, _meta: &[Node<NonCodeNode>]) {
-        // TODO use comments for docs (we can't currently get the comments for an argument)
+        result.with_comments(&arg.identifier.pre_comments);
+        result
     }
 
     pub fn get_autocomplete_snippet(&self, index: usize) -> Option<(usize, String)> {
@@ -885,6 +882,37 @@ impl ApplyMeta for TyData {
     }
 }
 
+impl ApplyMeta for ArgData {
+    fn apply_docs(
+        &mut self,
+        summary: Option<String>,
+        description: Option<String>,
+        _examples: Vec<(String, ExampleProperties)>,
+    ) {
+        let Some(mut docs) = summary else {
+            return;
+        };
+        if let Some(desc) = description {
+            docs.push_str("\n\n");
+            docs.push_str(&desc);
+        }
+
+        self.docs = Some(docs);
+    }
+
+    fn deprecated(&mut self, _deprecated: bool) {
+        unreachable!();
+    }
+
+    fn doc_hidden(&mut self, _doc_hidden: bool) {
+        unreachable!();
+    }
+
+    fn impl_kind(&mut self, _impl_kind: annotations::Impl) {
+        unreachable!();
+    }
+}
+
 fn collect_type_names(acc: &mut HashSet<String>, ty: &Type) {
     match ty {
         Type::Primitive(primitive_type) => {

rust/kcl-lib/src/parsing/parser.rs

@@ -2809,15 +2809,40 @@ fn uom_for_type(i: &mut TokenSlice) -> PResult<NumericSuffix> {
     any.try_map(|t: Token| t.value.parse()).parse_next(i)
 }
 
+fn comment(i: &mut TokenSlice) -> PResult<Node<String>> {
+    any.verify_map(|token: Token| {
+        let value = match token.token_type {
+            TokenType::LineComment => token.value,
+            TokenType::BlockComment => token.value,
+            _ => return None,
+        };
+        Some(Node::new(value, token.start, token.end, token.module_id))
+    })
+    .context(expected("Comment"))
+    .parse_next(i)
+}
+
+fn comments(i: &mut TokenSlice) -> PResult<Node<Vec<String>>> {
+    let comments: Vec<Node<String>> = repeat(1.., (comment, opt(whitespace)).map(|(c, _)| c)).parse_next(i)?;
+    let start = comments[0].start;
+    let module_id = comments[0].module_id;
+    let end = comments.last().unwrap().end;
+    let inner = comments.into_iter().map(|n| n.inner).collect();
+    Ok(Node::new(inner, start, end, module_id))
+}
+
 struct ParamDescription {
     labeled: bool,
     arg_name: Token,
     type_: std::option::Option<Node<Type>>,
     default_value: Option<DefaultParamVal>,
+    comments: Option<Node<Vec<String>>>,
 }
 
 fn parameter(i: &mut TokenSlice) -> PResult<ParamDescription> {
-    let (found_at_sign, arg_name, question_mark, _, type_, _ws, default_literal) = (
+    let (_, comments, found_at_sign, arg_name, question_mark, _, type_, _ws, default_literal) = (
+        opt(whitespace),
+        opt(comments),
         opt(at_sign),
         any.verify(|token: &Token| !matches!(token.token_type, TokenType::Brace) || token.value != ")"),
         opt(question_mark),
@@ -2827,6 +2852,7 @@ fn parameter(i: &mut TokenSlice) -> PResult<ParamDescription> {
         opt((equals, opt(whitespace), literal).map(|(_, _, literal)| literal)),
     )
         .parse_next(i)?;
+
     Ok(ParamDescription {
         labeled: found_at_sign.is_none(),
         arg_name,
@@ -2841,6 +2867,7 @@ fn parameter(i: &mut TokenSlice) -> PResult<ParamDescription> {
                 return Err(ErrMode::Backtrack(ContextError::from(e)));
             }
         },
+        comments,
     })
 }
 
@@ -2850,6 +2877,7 @@ fn parameters(i: &mut TokenSlice) -> PResult<Vec<Parameter>> {
     let candidates: Vec<_> = separated(0.., parameter, comma_sep)
         .context(expected("function parameters"))
         .parse_next(i)?;
+    opt(comma_sep).parse_next(i)?;
 
     // Make sure all those tokens are valid parameters.
     let params: Vec<Parameter> = candidates
@@ -2860,8 +2888,13 @@ fn parameters(i: &mut TokenSlice) -> PResult<Vec<Parameter>> {
                  arg_name,
                  type_,
                  default_value,
+                 comments,
              }| {
-                let identifier = Node::<Identifier>::try_from(arg_name)?;
+                let mut identifier = Node::<Identifier>::try_from(arg_name)?;
+                if let Some(comments) = comments {
+                    identifier.comment_start = comments.start;
+                    identifier.pre_comments = comments.inner;
+                }
 
                 Ok(Parameter {
                     identifier,

rust/kcl-lib/src/parsing/snapshots/kcl_lib__parsing__parser__snapshot_tests__kw_function_decl_first_unlabeled.snap

@@ -52,7 +52,7 @@ expression: actual
                 "commentStart": 8,
                 "end": 9,
                 "name": "x",
-                "start": 8,
+                "start": 7,
                 "type": "Identifier"
               },
               "labeled": false

rust/kcl-lib/std/sketch.kcl

@@ -22,4 +22,13 @@
 /// example = extrude(exampleSketch, length = 5)
 /// ```
 @(impl = std_rust)
-export fn circle(@sketch_or_surface: Sketch | Plane | Face, center: Point2d, radius: number, tag?: tag): Sketch {}
+export fn circle(
+  /// Sketch to extend, or plane or surface to sketch on.
+  @sketch_or_surface: Sketch | Plane | Face,
+  /// The center of the circle.
+  center: Point2d,
+  /// The radius of the circle.
+  radius: number,
+  /// Create a new tag which refers to this circle.
+  tag?: tag,
+): Sketch {}