Decl using the ast macro

parser/src/lib.rs

@@ -66,6 +66,10 @@ macro_rules! _ast_ti {
         $val::try_from($inner.next().unwrap())
     };
 
+    ($inner:ident, ? $val:ident) => {
+        $inner.next().map($val::try_from).transpose()
+    };
+
     ($inner:ident, ? ($rule:path)) => {
         $crate::parser::listen_rule(&mut $inner, $rule)
     };

parser/src/parser/common/decl.rs

@@ -13,11 +13,12 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for VarDeclStmt {
             Rule::var_decl_statement => {
                 let mut inner = pair.into_inner();
 
-                let decl = VarDecl::try_from(inner.next().unwrap()).get()?;
+                Ok(ast_expr!(
-
+                    inner@VarDeclStmt {
-                let init = inner.next().map(Expression::try_from).transpose().get()?;
+                        decl: @VarDecl,
-
+                        init: ?Expression
-                Ok(VarDeclStmt { decl, init })
+                    }
+                ))
             }
 
             _ => unimplemented!(),
@@ -33,11 +34,12 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for FieldDeclStmt {
             Rule::class_field => {
                 let mut inner = pair.into_inner();
 
-                let decl = FieldDecl::try_from(inner.next().unwrap()).get()?;
+                Ok(ast_expr!(
-
+                    inner@FieldDeclStmt {
-                let init = inner.next().map(Expression::try_from).transpose().get()?;
+                        decl: @FieldDecl,
-
+                        init: ?Expression
-                Ok(FieldDeclStmt { decl, init })
+                    }
+                ))
             }
 
             _ => unimplemented!(),
@@ -53,7 +55,8 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for VarDecl {
             Rule::var_decl => {
                 let mut inner = pair.into_inner();
 
-                Ok(ast_expr!(inner@VarDecl {
+                Ok(ast_expr!(
+                    inner@VarDecl {
                         type_: & (inner
                             .next()
                             .and_then(|pair| {
@@ -68,7 +71,8 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for VarDecl {
                         mutable: ?(Rule::mutable),
 
                         name: @Pattern
-                }))
+                    }
+                ))
             }
 
             _ => unimplemented!("{:?}", pair.as_rule()),
@@ -84,11 +88,13 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for FieldDecl {
             Rule::field => {
                 let mut inner = pair.into_inner();
 
-                Ok(ast_expr!(inner@FieldDecl {
+                Ok(ast_expr!(
+                    inner@FieldDecl {
                         visibility: !Visibility,
                         type_: @TypeExpr,
                         name: @Identifier
-                }))
+                    }
+                ))
             }
 
             _ => unimplemented!("{:?}", pair.as_rule()),