improve: add some comments for AST nodes

internal_macro/src/node_macro/src/lib.rs

@@ -1,6 +1,50 @@
 use proc_macro::TokenStream;
 use quote::quote;
 use syn::{parse_macro_input, DeriveInput};
+/// node is a macro to embed new fields, add some macros and implement
+/// crate::ast::node::FmtTrait and crate::ast::node::RangeTrait
+/// traits for the structure.
+/// currently, it supports arguemnts as 'comment' and 'copy':
+///
+/// The node without any argument embeds a new field 'range' into a structure
+/// ```rust
+/// #[node]
+/// pub struct demo {
+///     pub filed: i32,
+///     pub field2: String,
+/// }
+/// ```
+/// The embedded structure looks like:
+/// ```rust
+/// #[derive(Clone, PartialEq, Eq, derivative::Derivative)]
+/// #[derivative(Debug)]
+/// pub struct demo {
+///    pub filed: i32,
+///    pub field2: String,
+///    pub range: crate::ast::range::Range,
+/// }
+/// ```
+///
+/// If we pass the argument `comment`:
+/// ```rust
+/// #[node(comment)]
+/// pub struct demo {
+///     pub filed: i32,
+///     pub field2: String,
+/// }
+/// ```
+///
+/// The embedded structure looks like:
+/// ```rust
+/// #[derive(Clone, PartialEq, Eq, derivative::Derivative)]
+/// #[derivative(Debug)]
+/// pub struct demo {
+///    pub filed: i32,
+///    pub field2: String,
+///    pub comments: Vec<Vec<Box<crate::ast::node::NodeEnum>>>,
+///    pub range: crate::ast::range::Range,
+/// }
+/// ```
 #[proc_macro_attribute]
 pub fn node(args: TokenStream, input: TokenStream) -> TokenStream {
     let mut ast = parse_macro_input!(input as DeriveInput);

src/ast/fmt.rs

@@ -144,9 +144,9 @@ impl FmtBuilder {
     pub fn parse_use_node(&mut self, node: &UseNode) {
         self.token("use");
         self.space();
-        for (i, id) in node.ids.iter().enumerate() {
+        for (i, id) in node.namespace.iter().enumerate() {
             id.format(self);
-            if i != node.ids.len() - 1 {
+            if i != node.namespace.len() - 1 {
                 self.dbcolon();
             }
         }
@@ -158,9 +158,9 @@ impl FmtBuilder {
         self.enter();
     }
     pub fn parse_extern_id_node(&mut self, node: &ExternIdNode) {
-        for (i, id) in node.ns.iter().enumerate() {
+        for (i, id) in node.namespace.iter().enumerate() {
             id.format(self);
-            if i != node.ns.len() {
+            if i != node.namespace.len() {
                 self.dbcolon();
             }
         }
@@ -192,7 +192,7 @@ impl FmtBuilder {
         }
     }
     pub fn parse_struct_def_node(&mut self, node: &StructDefNode) {
-        for c in node.pre_comments.iter() {
+        for c in node.docs.iter() {
             c.format(self);
         }
         self.prefix();
@@ -303,12 +303,12 @@ impl FmtBuilder {
         self.token("let");
         self.space();
         node.var.format(self);
-        if let Some(tp) = &node.tp {
+        if let Some(tp) = &node.variable_type {
             self.colon();
             self.space();
             tp.format(self);
         }
-        if let Some(exp) = &node.exp {
+        if let Some(exp) = &node.value_expression {
             self.space();
             self.equal();
             self.space();
@@ -350,7 +350,7 @@ impl FmtBuilder {
         }
     }
     pub fn parse_ret_node(&mut self, node: &RetNode) {
-        if let Some((t, _)) = node.yiel {
+        if let Some((t, _)) = node.yield_identifier {
             self.token(t.get_str());
             self.space();
         }
@@ -713,7 +713,7 @@ impl FmtBuilder {
         self.r_paren();
     }
     pub fn parse_trait_bound_node(&mut self, node: &TraitBoundNode) {
-        node.generic.format(self);
+        node.identifier.format(self);
         if let Some(impl_trait) = &node.impl_trait {
             impl_trait.format(self);
         }
@@ -756,7 +756,7 @@ impl FmtBuilder {
         self.space();
         self.token("as");
         self.space();
-        node.ty.format(self);
+        node.target_type.format(self);
         if let Some((t, _)) = node.tail {
             if t == TokenType::QUESTION {
                 self.token("?");
@@ -770,7 +770,7 @@ impl FmtBuilder {
         self.space();
         self.token("is");
         self.space();
-        node.ty.format(self);
+        node.target_type.format(self);
     }
     pub fn parse_tuple_init_node(&mut self, node: &TupleInitNode) {
         self.l_paren();
@@ -788,7 +788,7 @@ impl FmtBuilder {
     }
     pub fn parse_tuple_type_node(&mut self, node: &TupleTypeNode) {
         self.l_paren();
-        for (i, ty) in node.tps.iter().enumerate() {
+        for (i, ty) in node.types.iter().enumerate() {
             if i > 0 {
                 self.comma();
                 self.space();
@@ -844,7 +844,7 @@ impl FmtBuilder {
     pub fn parse_global_const_node(&mut self, node: &GlobalConstNode) {
         self.token("const");
         self.space();
-        node.var.format(self);
+        node.constant.format(self);
         self.semicolon();
         // 顶层节点加空格
         self.enter();

src/ast/node/cast.rs

@@ -25,8 +25,14 @@ use crate::ast::node::RangeTrait;
 
 #[node]
 pub struct AsNode {
+    /// expr is the expression which calculates a value as output
     pub expr: Box<NodeEnum>,
-    pub ty: Box<TypeNodeEnum>,
+
+    /// target_type refers the desired type for the expr
+    pub target_type: Box<TypeNodeEnum>,
+
+    /// tail is the question or exclaimation mark following an 'as' statement
+    /// it will be None if no marks exist
     pub tail: Option<(TokenType, Range)>,
 }
 
@@ -37,10 +43,10 @@ impl Node for AsNode {
         builder: &'b BuilderEnum<'a, '_>,
     ) -> NodeResult {
         let re = self.expr.emit(ctx, builder);
-        self.ty.emit_highlight(ctx);
+        self.target_type.emit_highlight(ctx);
         let v = re?.get_value();
         let v = v.unwrap();
-        let target_tp = self.ty.get_type(ctx, builder, true)?;
+        let target_tp = self.target_type.get_type(ctx, builder, true)?;
         let (val, target_tp) = ctx.force_cast_safe(
             v.get_value(),
             &v.get_ty().borrow(),
@@ -58,7 +64,7 @@ impl PrintTrait for AsNode {
         tab(tabs, line.clone(), end);
         println!("AsNode");
         self.expr.print(tabs + 1, false, line.clone());
-        self.ty.print(tabs + 1, true, line.clone());
+        self.target_type.print(tabs + 1, true, line.clone());
     }
 }
 
@@ -88,14 +94,14 @@ impl<'a, 'ctx> Ctx<'a> {
             }
             (PLType::Union(union), target_ty) => {
                 if node.tail.is_none() {
-                    let pos = node.ty.range().end;
+                    let pos = node.target_type.range().end;
                     let end_range = Range {
                         start: pos,
                         end: pos,
                     };
                     return Err(node.range.new_err(ErrorCode::INVALID_DIRECT_UNION_CAST)
                         .add_label(node.expr.range(), self.get_file(), format_label!("type of the expression is `{}`", &union.name))
-                        .add_label(node.ty.range(), self.get_file(), format_label!("target type is `{}`", target_ty.get_name()))
+                        .add_label(node.target_type.range(), self.get_file(), format_label!("target type is `{}`", target_ty.get_name()))
                         .add_label(end_range, self.get_file(), format_label!("add `{}` or `{}` to make it legal", "?", "!"))
                         .add_help("cast a union to its member type directly is not allowed, use `?` or `!` after the cast expression")
                         .add_to_ctx(self));
@@ -124,7 +130,7 @@ impl<'a, 'ctx> Ctx<'a> {
                             format_label!("type of the expression is `{}`", &union.name),
                         )
                         .add_label(
-                            node.ty.range(),
+                            node.target_type.range(),
                             self.get_file(),
                             format_label!("target type is `{}`", target_ty.get_name()),
                         )
@@ -137,14 +143,14 @@ impl<'a, 'ctx> Ctx<'a> {
             }
             (PLType::Trait(t), target_ty) => {
                 if node.tail.is_none() {
-                    let pos = node.ty.range().end;
+                    let pos = node.target_type.range().end;
                     let end_range = Range {
                         start: pos,
                         end: pos,
                     };
                     return Err(node.range.new_err(ErrorCode::INVALID_DIRECT_TRAIT_CAST)
                         .add_label(node.expr.range(), self.get_file(), format_label!("type of the expression is `{}`", &t.name))
-                        .add_label(node.ty.range(), self.get_file(), format_label!("target type is `{}`", target_ty.get_name()))
+                        .add_label(node.target_type.range(), self.get_file(), format_label!("target type is `{}`", target_ty.get_name()))
                         .add_label(end_range, self.get_file(), format_label!("add `{}` or `{}` to make it legal", "?", "!"))
                         .add_help("cast a trait to specific type directly is not allowed, use `?` or `!` after the cast expression")
                         .add_to_ctx(self));
@@ -161,7 +167,7 @@ impl<'a, 'ctx> Ctx<'a> {
                     .up_cast(
                         target_ty.clone(),
                         Arc::new(RefCell::new(ty.clone())),
-                        node.ty.range(),
+                        node.target_type.range(),
                         node.expr.range(),
                         val,
                         builder,
@@ -175,7 +181,7 @@ impl<'a, 'ctx> Ctx<'a> {
                                 format_label!("type of the expression is `{}`", ty.get_name()),
                             )
                             .add_label(
-                                node.ty.range(),
+                                node.target_type.range(),
                                 self.get_file(),
                                 format_label!("target type is `{}`", target_ty.borrow().get_name()),
                             )
@@ -486,8 +492,10 @@ pub fn get_option_type<'a, 'b>(
 
 #[node]
 pub struct IsNode {
+    /// expr is the expression which calculates a value as output
     pub expr: Box<NodeEnum>,
-    pub ty: Box<TypeNodeEnum>,
+    /// target_type refers the desired type for the expr
+    pub target_type: Box<TypeNodeEnum>,
 }
 
 impl Node for IsNode {
@@ -497,9 +505,9 @@ impl Node for IsNode {
         builder: &'b BuilderEnum<'a, '_>,
     ) -> NodeResult {
         let re = self.expr.emit(ctx, builder);
-        self.ty.emit_highlight(ctx);
+        self.target_type.emit_highlight(ctx);
         let v = re?.get_value().unwrap();
-        let target_tp = self.ty.get_type(ctx, builder, true)?;
+        let target_tp = self.target_type.get_type(ctx, builder, true)?;
         let val = v.get_value();
         let binding = v.get_ty();
         let tp = &*binding.borrow();
@@ -528,7 +536,7 @@ impl Node for IsNode {
                         .to_result()
                 } else {
                     Err(self
-                        .ty
+                        .target_type
                         .range()
                         .new_err(ErrorCode::UNION_DOES_NOT_CONTAIN_TYPE)
                         .add_to_ctx(ctx))
@@ -570,6 +578,6 @@ impl PrintTrait for IsNode {
         tab(tabs, line.clone(), end);
         println!("IsNode");
         self.expr.print(tabs + 1, false, line.clone());
-        self.ty.print(tabs + 1, true, line.clone());
+        self.target_type.print(tabs + 1, true, line.clone());
     }
 }

src/ast/node/control.rs

@@ -7,9 +7,16 @@ use crate::ast::pltype::PriType;
 use internal_macro::node;
 
 #[node(comment)]
+/// IfNode is consisted by a 'if' clause and a 'else' clause.
+/// the 'else' clause is allowed to embed another IfNode
 pub struct IfNode {
+    /// condition is the bool expression for the if keyword
+    /// there is no type check in the AST stage, but we did check it when lowering ast
     pub cond: Box<NodeEnum>,
+    /// then is the logic to be executed if the cond is true
     pub then: Box<StatementsNode>,
+    /// els stands for the left part of the condition clause
+    /// it might be another IfNode or a statement
     pub els: Option<Box<NodeEnum>>,
 }
 
@@ -159,6 +166,20 @@ impl Node for WhileNode {
 }
 
 #[node(comment)]
+/// ForNode is consisted by four parts: pre,cond, opt and body in the format of `for pre;cond;opt body`.
+///
+/// The pre and opt are optional, but the semi-colons are compulsory.
+///
+/// For example:
+/// ```pi
+/// for let i = 0; i < 5; i = i + 1{
+///  // ^pre       ^cond  ^opt        
+///  
+///  println!(i)
+///  // ^body
+/// }
+///
+/// ```
 pub struct ForNode {
     pub pre: Option<Box<NodeEnum>>,
     pub cond: Box<NodeEnum>,

src/ast/node/function.rs

@@ -452,14 +452,21 @@ fn handle_ret<'a, 'b>(
 }
 #[node]
 pub struct FuncDefNode {
+    /// id is the function identifier
     pub id: Box<VarNode>,
+    /// paralist is the parameter lists
     pub paralist: Vec<Box<TypedIdentifierNode>>,
+    /// ret is the return type of the function
     pub ret: Box<TypeNodeEnum>,
+    /// docs is the documentation of the structure started with `///`
     pub doc: Vec<Box<NodeEnum>>,
+    /// pre_comments is the comments above a structure
     pub pre_comments: Vec<Box<NodeEnum>>,
-    pub declare: bool,
+    /// is_declaration_only refers whether this function is a declaration only, which means it has no body
+    pub is_declaration_only: bool,
     pub generics: Option<Box<GenericDefNode>>,
     pub body: Option<StatementsNode>,
+    /// modifier indicates whether the trait is decorated by a keyword `pub`
     pub modifier: Option<(TokenType, Range)>,
     pub generics_size: usize, // the size of generics except the generics from impl node
     pub trait_bounds: Option<Vec<Box<TraitBoundNode>>>,
@@ -531,7 +538,7 @@ impl TypeNode for FuncDefNode {
                 param_names: param_name,
                 range: self.id.range(),
                 doc: self.doc.clone(),
-                llvmname: if self.declare {
+                llvmname: if self.is_declaration_only {
                     if self.id.name.starts_with('|') {
                         return Err(self
                             .range
@@ -562,7 +569,7 @@ impl TypeNode for FuncDefNode {
                 node: Some(Box::new(self.clone())),
                 body_range: self.range,
                 in_trait: self.in_trait_def,
-                is_declare: self.declare,
+                is_declare: self.is_declaration_only,
             };
             if self.generics.is_none() {
                 builder.get_or_insert_fn_handle(&fnvalue, child);