Extract doc-comment on plugin functions.

CHANGELOG.md

@@ -17,6 +17,7 @@ Enhancements
 
 * Added `NativeCallContext::call_fn` to easily call a function.
 * A new syntax is introduced for `def_package!` that will replace the old syntax in future versions.
+* Doc-comments on plugin module functions are extracted into the functions' metadata.
 
 Deprecated API's
 ----------------

codegen/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rhai_codegen"
-version = "1.2.0"
+version = "1.3.0"
 edition = "2018"
 authors = ["jhwgh1968", "Stephen Chung"]
 description = "Procedural macros support package for Rhai, a scripting language and engine for Rust"
@@ -16,7 +16,7 @@ default = []
 metadata = []
 
 [dev-dependencies]
-rhai = { path = "..", version = "1.1" }
+rhai = { path = "..", version = "1.4" }
 trybuild = "1"
 
 [dependencies]

codegen/src/attrs.rs

@@ -117,18 +117,60 @@ pub fn inner_item_attributes<T: ExportedParams>(
     attrs: &mut Vec<syn::Attribute>,
     attr_name: &str,
 ) -> syn::Result<T> {
-    // Find the #[rhai_fn] attribute which will turn be read for the function parameters.
+    // Find the #[rhai_fn] attribute which will turn be read for function parameters.
-    if let Some(rhai_fn_idx) = attrs
+    if let Some(index) = attrs
         .iter()
         .position(|a| a.path.get_ident().map(|i| *i == attr_name).unwrap_or(false))
     {
-        let rhai_fn_attr = attrs.remove(rhai_fn_idx);
+        let rhai_fn_attr = attrs.remove(index);
+
+        // Cannot have more than one #[rhai_fn]
+        if let Some(duplicate) = attrs
+            .iter()
+            .find(|a| a.path.get_ident().map(|i| *i == attr_name).unwrap_or(false))
+        {
+            return Err(syn::Error::new(
+                duplicate.span(),
+                format!("duplicated attribute '{}'", attr_name),
+            ));
+        }
+
         rhai_fn_attr.parse_args_with(T::parse_stream)
     } else {
         Ok(T::no_attrs())
     }
 }
 
+#[cfg(feature = "metadata")]
+pub fn doc_attribute(attrs: &mut Vec<syn::Attribute>) -> syn::Result<String> {
+    // Find the #[doc] attribute which will turn be read for function documentation.
+    let mut comments = String::new();
+
+    while let Some(index) = attrs
+        .iter()
+        .position(|attr| attr.path.get_ident().map(|i| *i == "doc").unwrap_or(false))
+    {
+        let attr = attrs.remove(index);
+        let meta = attr.parse_meta()?;
+
+        match meta {
+            syn::Meta::NameValue(syn::MetaNameValue {
+                lit: syn::Lit::Str(s),
+                ..
+            }) => {
+                if !comments.is_empty() {
+                    comments += "\n";
+                }
+
+                comments += &s.value();
+            }
+            _ => continue,
+        }
+    }
+
+    Ok(comments)
+}
+
 pub fn collect_cfg_attr(attrs: &[syn::Attribute]) -> Vec<syn::Attribute> {
     attrs
         .iter()

codegen/src/function.rs

@@ -282,6 +282,8 @@ pub struct ExportedFn {
     mut_receiver: bool,
     params: ExportedFnParams,
     cfg_attrs: Vec<syn::Attribute>,
+    #[cfg(feature = "metadata")]
+    comment: String,
 }
 
 impl Parse for ExportedFn {
@@ -404,6 +406,8 @@ impl Parse for ExportedFn {
             mut_receiver,
             params: Default::default(),
             cfg_attrs,
+            #[cfg(feature = "metadata")]
+            comment: Default::default(),
         })
     }
 }
@@ -503,6 +507,16 @@ impl ExportedFn {
         }
     }
 
+    #[cfg(feature = "metadata")]
+    pub fn comment(&self) -> &str {
+        &self.comment
+    }
+
+    #[cfg(feature = "metadata")]
+    pub fn set_comment(&mut self, comment: String) {
+        self.comment = comment
+    }
+
     pub fn set_cfg_attrs(&mut self, cfg_attrs: Vec<syn::Attribute>) {
         self.cfg_attrs = cfg_attrs
     }

codegen/src/module.rs

@@ -117,18 +117,22 @@ impl Parse for Module {
                     syn::Item::Fn(f) => Some(f),
                     _ => None,
                 })
-                .try_fold(Vec::new(), |mut vec, item_fn| {
+                .try_fold(Vec::new(), |mut vec, item_fn| -> syn::Result<_> {
                     let params =
                         crate::attrs::inner_item_attributes(&mut item_fn.attrs, "rhai_fn")?;
 
-                    syn::parse2::<ExportedFn>(item_fn.to_token_stream())
+                    let f =
-                        .and_then(|mut f| {
+                        syn::parse2(item_fn.to_token_stream()).and_then(|mut f: ExportedFn| {
                             f.set_params(params)?;
                             f.set_cfg_attrs(crate::attrs::collect_cfg_attr(&item_fn.attrs));
+
+                            #[cfg(feature = "metadata")]
+                            f.set_comment(crate::attrs::doc_attribute(&mut item_fn.attrs)?);
                             Ok(f)
-                        })
+                        })?;
-                        .map(|f| vec.push(f))
+
-                        .map(|_| vec)
+                    vec.push(f);
+                    Ok(vec)
                 })?;
             // Gather and parse constants definitions.
             for item in content.iter() {

codegen/src/rhai_module.rs

@@ -166,20 +166,30 @@ pub fn generate_body(
             );
 
             #[cfg(feature = "metadata")]
-            let param_names = quote! {
+            let (param_names, comment) = (
-                Some(#fn_token_name::PARAM_NAMES)
+                quote! { Some(#fn_token_name::PARAM_NAMES) },
-            };
+                function.comment(),
+            );
             #[cfg(not(feature = "metadata"))]
-            let param_names = quote! { None };
+            let (param_names, comment) = (quote! { None }, "");
 
-            set_fn_statements.push(
+            set_fn_statements.push(if comment.is_empty() {
                 syn::parse2::<syn::Stmt>(quote! {
                     #(#cfg_attrs)*
                     m.set_fn(#fn_literal, FnNamespace::#ns_str, FnAccess::Public,
                              #param_names, &[#(#fn_input_types),*], #fn_token_name().into());
                 })
-                .unwrap(),
+                .unwrap()
-            );
+            } else {
+                let comment_literal = syn::LitStr::new(comment, Span::call_site());
+
+                syn::parse2::<syn::Stmt>(quote! {
+                    #(#cfg_attrs)*
+                    m.set_fn_with_comment(#fn_literal, FnNamespace::#ns_str, FnAccess::Public,
+                             #param_names, &[#(#fn_input_types),*], #comment_literal, #fn_token_name().into());
+                })
+                .unwrap()
+            });
         }
 
         gen_fn_tokens.push(quote! {

codegen/src/test/module.rs

@@ -37,6 +37,36 @@ mod module_tests {
         );
     }
 
+    #[test]
+    fn one_factory_fn_with_comment_module() {
+        let input_tokens: TokenStream = quote! {
+            pub mod one_fn {
+                /// This is a doc-comment.
+                /// Another line.
+                /** block doc-comment */
+                // Regular comment
+                /// Final line.
+                /** doc-comment
+                    in multiple lines
+                 */
+                pub fn get_mystic_number() -> INT {
+                    42
+                }
+            }
+        };
+
+        let item_mod = syn::parse2::<Module>(input_tokens).unwrap();
+        assert!(item_mod.consts().is_empty());
+        assert_eq!(item_mod.fns().len(), 1);
+        assert_eq!(item_mod.fns()[0].name().to_string(), "get_mystic_number");
+        assert_eq!(item_mod.fns()[0].comment(), " This is a doc-comment.\n Another line.\n block doc-comment \n Final line.\n doc-comment\n                    in multiple lines\n                 ");
+        assert_eq!(item_mod.fns()[0].arg_count(), 0);
+        assert_eq!(
+            item_mod.fns()[0].return_type().unwrap(),
+            &syn::parse2::<syn::Type>(quote! { INT }).unwrap()
+        );
+    }
+
     #[test]
     fn one_single_arg_fn_module() {
         let input_tokens: TokenStream = quote! {
@@ -323,6 +353,66 @@ mod generate_tests {
         assert_streams_eq(item_mod.generate(), expected_tokens);
     }
 
+    #[test]
+    fn one_factory_fn_with_comment_module() {
+        let input_tokens: TokenStream = quote! {
+            pub mod one_fn {
+                /// This is a doc-comment.
+                /// Another line.
+                /** block doc-comment */
+                // Regular comment
+                /// Final line.
+                /** doc-comment
+                    in multiple lines
+                 */
+                pub fn get_mystic_number() -> INT {
+                    42
+                }
+            }
+        };
+
+        let expected_tokens = quote! {
+            pub mod one_fn {
+                pub fn get_mystic_number() -> INT {
+                    42
+                }
+                #[allow(unused_imports)]
+                use super::*;
+
+                pub fn rhai_module_generate() -> Module {
+                    let mut m = Module::new();
+                    rhai_generate_into_module(&mut m, false);
+                    m.build_index();
+                    m
+                }
+                #[allow(unused_mut)]
+                pub fn rhai_generate_into_module(m: &mut Module, flatten: bool) {
+                    m.set_fn_with_comment("get_mystic_number", FnNamespace::Internal, FnAccess::Public,
+                             Some(get_mystic_number_token::PARAM_NAMES), &[], " This is a doc-comment.\n Another line.\n block doc-comment \n Final line.\n doc-comment\n                    in multiple lines\n                 ",
+                             get_mystic_number_token().into());
+                    if flatten {} else {}
+                }
+                #[allow(non_camel_case_types)]
+                pub struct get_mystic_number_token();
+                impl get_mystic_number_token {
+                    pub const PARAM_NAMES: &'static [&'static str] = &["INT"];
+                    #[inline(always)] pub fn param_types() -> [TypeId; 0usize] { [] }
+                }
+                impl PluginFunction for get_mystic_number_token {
+                    #[inline(always)]
+                    fn call(&self, context: NativeCallContext, args: &mut [&mut Dynamic]) -> RhaiResult {
+                        Ok(Dynamic::from(get_mystic_number()))
+                    }
+
+                    #[inline(always)] fn is_method_call(&self) -> bool { false }
+                }
+            }
+        };
+
+        let item_mod = syn::parse2::<Module>(input_tokens).unwrap();
+        assert_streams_eq(item_mod.generate(), expected_tokens);
+    }
+
     #[test]
     fn one_single_arg_global_fn_module() {
         let input_tokens: TokenStream = quote! {

codegen/ui_tests/rhai_fn_duplicate_attr.rs

@@ -0,0 +1,18 @@
+use rhai::plugin::*;
+
+#[export_module]
+pub mod test_module {
+    #[rhai_fn(name = "test")]
+    #[rhai_fn(pure)]
+    pub fn test_fn(input: Point) -> bool {
+        input.x > input.y
+    }
+}
+
+fn main() {
+    if test_module::test_fn(n) {
+        println!("yes");
+    } else {
+        println!("no");
+    }
+}

codegen/ui_tests/rhai_fn_duplicate_attr.stderr

@@ -0,0 +1,17 @@
+error: duplicated attribute 'rhai_fn'
+ --> ui_tests/rhai_fn_duplicate_attr.rs:6:5
+  |
+6 |     #[rhai_fn(pure)]
+  |     ^^^^^^^^^^^^^^^^
+
+error[E0433]: failed to resolve: use of undeclared crate or module `test_module`
+  --> ui_tests/rhai_fn_duplicate_attr.rs:13:8
+   |
+13 |     if test_module::test_fn(n) {
+   |        ^^^^^^^^^^^ use of undeclared crate or module `test_module`
+
+error[E0425]: cannot find value `n` in this scope
+  --> ui_tests/rhai_fn_duplicate_attr.rs:13:29
+   |
+13 |     if test_module::test_fn(n) {
+   |                             ^ not found in this scope

src/module/mod.rs

@@ -10,7 +10,7 @@ use crate::tokenizer::Token;
 use crate::types::dynamic::Variant;
 use crate::{
     calc_fn_params_hash, calc_qualified_fn_hash, combine_hashes, Dynamic, EvalAltResult,
-    Identifier, ImmutableString, NativeCallContext, Shared, StaticVec,
+    Identifier, ImmutableString, NativeCallContext, Shared, SmartString, StaticVec,
 };
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
@@ -53,6 +53,9 @@ pub struct FuncInfo {
     /// Return type name.
     #[cfg(feature = "metadata")]
     pub return_type_name: Identifier,
+    /// Comments.
+    #[cfg(feature = "metadata")]
+    pub comments: SmartString,
 }
 
 impl FuncInfo {
@@ -488,6 +491,11 @@ impl Module {
                 param_names_and_types,
                 #[cfg(feature = "metadata")]
                 return_type_name: self.identifiers.get("Dynamic"),
+                #[cfg(feature = "metadata")]
+                comments: fn_def
+                    .comments
+                    .as_ref()
+                    .map_or(SmartString::new_const(), |v| v.join("\n").into()),
                 func: Into::<CallableFunction>::into(fn_def).into(),
             }
             .into(),
@@ -750,6 +758,8 @@ impl Module {
                 param_names_and_types: param_names,
                 #[cfg(feature = "metadata")]
                 return_type_name,
+                #[cfg(feature = "metadata")]
+                comments: SmartString::new_const(),
                 func: func.into(),
             }
             .into(),
@@ -761,6 +771,47 @@ impl Module {
         hash_fn
     }
 
+    /// _(metadata)_ Set a Rust function into the [`Module`], returning a non-zero hash key.
+    /// Exported under the `metadata` feature only.
+    ///
+    /// If there is an existing Rust function of the same hash, it is replaced.
+    ///
+    /// # WARNING - Low Level API
+    ///
+    /// This function is very low level.
+    ///
+    /// ## Parameter Names and Types
+    ///
+    /// Each parameter name/type pair should be a single string of the format: `var_name: type`.
+    ///
+    /// ## Return Type
+    ///
+    /// The _last entry_ in the list should be the _return type_ of the function.
+    /// In other words, the number of entries should be one larger than the number of parameters.
+    #[cfg(feature = "metadata")]
+    #[inline]
+    pub fn set_fn_with_comment(
+        &mut self,
+        name: impl AsRef<str> + Into<Identifier>,
+        namespace: FnNamespace,
+        access: FnAccess,
+        arg_names: Option<&[&str]>,
+        arg_types: &[TypeId],
+        comment: impl Into<SmartString>,
+        func: CallableFunction,
+    ) -> u64 {
+        let hash = self.set_fn(name, namespace, access, arg_names, arg_types, func);
+
+        let comment = comment.into();
+
+        if !comment.is_empty() {
+            let f = self.functions.get_mut(&hash).expect("exists");
+            f.comments = comment;
+        }
+
+        hash
+    }
+
     /// Set a Rust function taking a reference to the scripting [`Engine`][crate::Engine],
     /// the current set of functions, plus a list of mutable [`Dynamic`] references
     /// into the [`Module`], returning a non-zero hash key.

src/serde/metadata.rs

@@ -60,7 +60,7 @@ impl PartialOrd for FnParam<'_> {
         Some(match self.name.partial_cmp(&other.name).expect("succeed") {
             Ordering::Less => Ordering::Less,
             Ordering::Greater => Ordering::Greater,
-            Ordering::Equal => self.typ.partial_cmp(other.typ).expect("succeed"),
+            Ordering::Equal => self.typ.partial_cmp(&other.typ).expect("succeed"),
         })
     }
 }
@@ -162,7 +162,14 @@ impl<'a> From<&'a crate::module::FuncInfo> for FnMetadata<'a> {
                     .as_ref()
                     .map_or_else(|| Vec::new(), |v| v.iter().map(|s| &**s).collect())
             } else {
+                #[cfg(not(feature = "metadata"))]
+                {
                     Vec::new()
+                }
+                #[cfg(feature = "metadata")]
+                {
+                    info.comments.split("\n").collect()
+                }
             },
         }
     }