Ast expression macro

parser/src/error.rs

@@ -10,10 +10,10 @@ pub enum ParseError<'a, T> {
 
 #[derive(Debug, Clone)]
 pub struct AstError<'a, T> {
-    span: pest::Span<'a>,
-    error_code: ErrorCode,
-    error_message: String,
-    recovered: Option<T>,
+    pub span: pest::Span<'a>,
+    pub error_code: ErrorCode,
+    pub error_message: String,
+    pub recovered: Option<T>,
 }
 
 #[derive(Debug, Clone)]
@@ -89,7 +89,7 @@ where
             span: ast_err.span,
             error_code: ast_err.error_code,
             error_message: ast_err.error_message,
-            recovered: None,
+            recovered: Some(items),
         }),
         None => Ok(items),
     }

parser/src/lib.rs

@@ -26,3 +26,51 @@ pub fn parse<'a>(source: &'a str) -> Result<Vec<TopLevel>, ParseError<'a, Vec<To
 
     Ok(statements)
 }
+
+#[macro_export]
+macro_rules! ast_expr {
+    ($inner:tt@$item:path { $($name:ident $t:tt $val:tt $($val2:tt)?),*}) => {{
+        $(
+            let $name = $crate::_ast_t!($t $crate::_ast_ti!($inner, $val $($val2)?));
+        )*
+
+        $item { $($name,)* }
+    }};
+}
+
+#[macro_export]
+macro_rules! _ast_t {
+    (: $val:expr) => {
+        $val.get()?
+    };
+
+    (? $val:expr) => {
+        $val.or_else(|e| {
+            if let Some(recovered) = e.recovered {
+                Ok(recovered)
+            } else {
+                Err(e)
+            }
+        })
+        .get()?
+    };
+}
+
+#[macro_export]
+macro_rules! _ast_ti {
+    ($inner:ident, ! $val:ident) => {
+        $val::try_from(&mut $inner)
+    };
+
+    ($inner:ident, @ $val:ident) => {
+        $val::try_from($inner.next().unwrap())
+    };
+
+    ($inner:ident, ? ($rule:path)) => {
+        $crate::parser::listen_rule(&mut $inner, $rule)
+    };
+
+    ($inner:ident, & $val:expr) => {
+        $val
+    };
+}

parser/src/parser/common/decl.rs

@@ -1,8 +1,8 @@
 use crate::{
     Rule,
     ast::*,
+    ast_expr,
     error::{AstError, GetParseError},
-    parser::listen_rule,
 };
 
 impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for VarDeclStmt {
@@ -53,27 +53,22 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for VarDecl {
             Rule::var_decl => {
                 let mut inner = pair.into_inner();
 
-                let type_ = inner
-                    .next()
-                    .and_then(|pair| {
-                        if pair.as_str().trim() == "var" {
-                            None
-                        } else {
-                            Some(TypeExpr::try_from(pair))
-                        }
-                    })
-                    .transpose()
-                    .get()?;
+                Ok(ast_expr!(inner@VarDecl {
+                    type_: & (inner
+                        .next()
+                        .and_then(|pair| {
+                            if pair.as_str().trim() == "var" {
+                                None
+                            } else {
+                                Some(TypeExpr::try_from(pair))
+                            }
+                        })
+                        .transpose()),
 
-                let mutable = listen_rule(&mut inner, Rule::mutable);
+                    mutable: ?(Rule::mutable),
 
-                let name = Pattern::try_from(inner.next().unwrap()).get()?;
-
-                Ok(VarDecl {
-                    mutable,
-                    name,
-                    type_,
-                })
+                    name: @Pattern
+                }))
             }
 
             _ => unimplemented!("{:?}", pair.as_rule()),
@@ -89,15 +84,11 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for FieldDecl {
             Rule::field => {
                 let mut inner = pair.into_inner();
 
-                let visibility = Visibility::try_from(&mut inner).get()?;
-                let type_ = TypeExpr::try_from(inner.next().unwrap()).get()?;
-                let name = Identifier::try_from(inner.next().unwrap()).get()?;
-
-                Ok(FieldDecl {
-                    visibility,
-                    type_,
-                    name,
-                })
+                Ok(ast_expr!(inner@FieldDecl {
+                    visibility: !Visibility,
+                    type_: @TypeExpr,
+                    name: @Identifier
+                }))
             }
 
             _ => unimplemented!("{:?}", pair.as_rule()),

parser/src/parser/common/expr.rs

@@ -1,7 +1,7 @@
 use crate::{
     Rule,
     ast::*,
-    error::{AstError, AstResult},
+    error::{AstError, AstResult, GetParseError},
 };
 
 impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for Expression {
@@ -72,7 +72,7 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for Postfix {
         Ok(match rule {
             Rule::postfix => Postfix::try_from(inner.next().unwrap())?,
 
-            Rule::field_px => Postfix::FieldAccess(Identifier::try_from(inner.next().unwrap())?),
+            Rule::field_px => Postfix::FieldAccess(Identifier::try_from(inner.next().unwrap()).get()?),
 
             Rule::call_px => Postfix::Call(inner.map(Expression::try_from).collect::<AstResult<
                 'a,

parser/src/parser/mod.rs

@@ -1,9 +1,12 @@
 pub mod common;
 pub mod items;
 
-use crate::Rule;
+use crate::{Rule, error::AstResult};
 
-pub fn listen_rule(pairs: &mut pest::iterators::Pairs<'_, Rule>, rule: Rule) -> bool {
+pub fn listen_rule<'a>(
+    pairs: &mut pest::iterators::Pairs<'_, Rule>,
+    rule: Rule,
+) -> AstResult<'a, bool> {
     let consumed = pairs
         .peek()
         .map(|p| p.as_rule() == rule)
@@ -13,7 +16,7 @@ pub fn listen_rule(pairs: &mut pest::iterators::Pairs<'_, Rule>, rule: Rule) ->
         pairs.next();
     }
 
-    consumed
+    Ok(consumed)
 }
 
 pub fn consume_rule<'a>(