lex ;

components/lox-ir/src/syntax.rs

@@ -57,3 +57,9 @@ impl<'db> salsa::DebugWithDb<dyn crate::Db + 'db> for Expr {
         }
     }
 }
+
+
+pub enum Stmt {
+    // expression statement, like `1 + 2;`
+    Expr(Expr),
+}

components/lox-ir/src/token.rs

@@ -31,6 +31,9 @@ pub enum Token {
     // String
     String(Word),
 
+    // Semicolon
+    Semicolon,
+
     // Unkown token
     Unknown(char),
 }
@@ -52,6 +55,7 @@ impl<'db> DebugWithDb<dyn crate::Db + 'db> for Token {
             Token::Tree(tree) => f.debug_tuple("Tree").field(tree).finish(),
             Token::String(word) => write!(f, "String({})", word.as_str(db)),
             Token::Unknown(ch) => write!(f, "Unknown({})", ch),
+            Token::Semicolon => write!(f, "Semicolon"),
         }
     }
 }
@@ -66,6 +70,7 @@ impl Token {
             Token::Comment(s) => *s,
             Token::Tree(tree) => tree.span(db).len(),
             Token::String(s) => s.as_str(db).len() as u32,
+            Token::Semicolon => 1,
         }
     }
 

components/lox-lex/src/lex.rs

@@ -88,6 +88,9 @@ where
                 ' ' => {
                     push_token(Token::Whitespace(ch));
                 }
+                ';' => {
+                    push_token(Token::Semicolon);
+                }
                 _ => {
                     if ch.is_whitespace() {
                         push_token(Token::Whitespace(ch))

components/lox-parse/src/parser.rs

@@ -3,7 +3,7 @@ use lox_ir::{
     input_file::InputFile,
     kw::Keyword,
     span::Span,
-    syntax::{Expr, Op},
+    syntax::{Expr, Op, Stmt},
     token::Token,
     token_tree::TokenTree,
 };
@@ -42,6 +42,12 @@ impl<'me> Parser<'me> {
         exprs
     }
 
+    // fn expr_stmt(&mut self) -> Option<Stmt> {
+    //     let expr = self.parse_expr()?;
+    //     self.eat(Token::Semicolon);
+    //     Some(Stmt::Expr(expr))
+    // }
+
     // expression     → equality ;
     // equality       → comparison ( ( "!=" | "==" ) comparison )* ;
     // comparison     → term ( ( ">" | ">=" | "<" | "<=" ) term )* ;

lox_tests/string.lox

@@ -1 +1 @@
-"hello" + " world"
+"hello" + " world";

lox_tests/string.syntax

@@ -3,3 +3,15 @@ BinaryOp {
     op: Plus,
     right: StringLiteral( world),
 }
+Diagnostic {
+    severity: Error,
+    span: @14..@15,
+    message: "extra tokens after expression",
+    labels: [
+        Label {
+            span: @14..@15,
+            message: "here",
+        },
+    ],
+    children: [],
+}

lox_tests/string.token

@@ -1,10 +1,11 @@
 TokenTree {
-    source text: "\"hello\" + \" world\"",
+    source text: "\"hello\" + \" world\";",
     tokens: [
         String(hello),
         Whitespace(' '),
         Op(+),
         Whitespace(' '),
         String( world),
+        Semicolon,
     ],
 }