Update: Function #65

crates/parser/src/ast/top_level.rs

@@ -97,7 +97,7 @@ pub struct FunctionDecl {
     pub name: Identifier,
     pub generics: GenericsDecl,
     pub params: ParamList,
-    pub return_type: TypeExpr,
+    pub return_type: Option<TypeExpr>,
     pub body: Option<Block>,
 }
 

crates/parser/src/grammar.pest

@@ -192,7 +192,7 @@ attributes = {
 // DECLARATION HELPERS
 // ======================================================
 var_decl = {
-    "let" ~ WHITESPACE ~ pattern ~ type_expr?
+    "let" ~ pattern ~ type_expr?
 }
 
 field = {
@@ -323,7 +323,7 @@ trait_decl = {
 // ======================================================
 
 function_decl = {
-    visibility? ~ type_expr ~ identifier ~ generics_decl? ~ "(" ~ method_args ~ ")" ~ (block | semicolon)
+    visibility? ~ "fn" ~ identifier ~ generics_decl? ~ "(" ~ method_args ~ ")" ~ type_expr? ~ (block | semicolon)
 }
 
 // ======================================================

crates/parser/src/parser/items/function.rs

@@ -13,7 +13,6 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for FunctionDecl {
         ast_ensure!(pair, Rule::function_decl => {
         let mut inner = pair.into_inner();
             let visibility = Visibility::try_from(&mut inner);
-            let return_type = TypeExpr::try_from(inner.next().unwrap());
             let name = Identifier::try_from(inner.next().unwrap());
 
             let generics = consume_rule(&mut inner, Rule::generics_decl)
@@ -51,6 +50,10 @@ impl<'a> TryFrom<pest::iterators::Pair<'a, Rule>> for FunctionDecl {
                 })
                 .unwrap_or_else(|| Ok(ParamList(self_param.into_iter().collect())));
 
+            let return_type = consume_rule(&mut inner, Rule::type_expr)
+                .map(TypeExpr::try_from)
+                .transpose();
+
             let body = inner.next().map(Block::try_from).transpose();
 
             ast_expr!(Self {