From 316432856808c238a57508810d05d4fec5231821 Mon Sep 17 00:00:00 2001
From: Schrottkatze <git@schrottkatze.de>
Date: Wed, 23 Oct 2024 10:52:44 +0200
Subject: [PATCH] implement multiple members, member_values and trailing
 commata

---
 crates/json-pawarser/src/grammar.rs      | 21 +++++++++++++++++--
 crates/json-pawarser/src/lib.rs          | 26 ------------------------
 crates/json-pawarser/src/syntax_error.rs |  2 ++
 crates/json-pawarser/src/syntax_kind.rs  |  3 +++
 4 files changed, 24 insertions(+), 28 deletions(-)

diff --git a/crates/json-pawarser/src/grammar.rs b/crates/json-pawarser/src/grammar.rs
index 466f22c..b7afe02 100644
--- a/crates/json-pawarser/src/grammar.rs
+++ b/crates/json-pawarser/src/grammar.rs
@@ -33,9 +33,23 @@ mod object {
         }
 
         member(p);
+        while p.at(SyntaxKind::COMMA) {
+            // not always an error, later configurable
+            let potential_unexpected_comma = p.start("potential_unexpected_comma");
+            p.eat(SyntaxKind::COMMA);
 
-        p.eat(SyntaxKind::BRACE_CLOSE);
-        Some(obj_start.complete(p, SyntaxKind::OBJECT))
+            if member(p).is_none() {
+                potential_unexpected_comma.complete(p, SyntaxKind::TRAILING_COMMA);
+            } else {
+                potential_unexpected_comma.abandon(p);
+            }
+        }
+
+        Some(if !p.eat(SyntaxKind::BRACE_CLOSE) {
+            obj_start.error(p, SyntaxError::UnclosedObject)
+        } else {
+            obj_start.complete(p, SyntaxKind::OBJECT)
+        })
     }
 
     fn member(p: &mut Parser) -> Option<CompletedMarker> {
@@ -56,9 +70,12 @@ mod object {
             todo!("handle wrong tokens")
         }
 
+        let member_value_start = p.start("member_value_start");
         if value(p) {
+            member_value_start.complete(p, SyntaxKind::MEMBER_VALUE);
             Some(member_start.complete(p, SyntaxKind::MEMBER))
         } else {
+            member_value_start.abandon(p);
             let e = member_start.error(p, SyntaxError::MemberMissingValue);
             Some(
                 e.precede(p, "member but failed already")
diff --git a/crates/json-pawarser/src/lib.rs b/crates/json-pawarser/src/lib.rs
index 05c529e..89160be 100644
--- a/crates/json-pawarser/src/lib.rs
+++ b/crates/json-pawarser/src/lib.rs
@@ -1,29 +1,3 @@
 mod grammar;
 mod syntax_error;
 mod syntax_kind;
-
-#[cfg(test)]
-mod test {
-    use pawarser::parser::ParserBuilder;
-
-    use crate::{
-        grammar::{value, Parser},
-        syntax_kind::{lex, SyntaxKind},
-    };
-
-    #[test]
-    fn test() {
-        const TEST_DATA: &str = r#"{"hello_world": "meow"}"#;
-        let toks = lex(TEST_DATA);
-
-        let mut p: Parser = ParserBuilder::new(toks)
-            .add_meaningless(SyntaxKind::WHITESPACE)
-            .add_meaningless(SyntaxKind::NEWLINE)
-            .build();
-
-        value(&mut p);
-
-        let out = p.finish();
-        assert_eq!("", format!("{:#?}", out))
-    }
-}
diff --git a/crates/json-pawarser/src/syntax_error.rs b/crates/json-pawarser/src/syntax_error.rs
index 45bb5bd..b607be1 100644
--- a/crates/json-pawarser/src/syntax_error.rs
+++ b/crates/json-pawarser/src/syntax_error.rs
@@ -2,7 +2,9 @@ use crate::syntax_kind::SyntaxKind;
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum SyntaxError {
+    UnclosedObject,
     DisallowedKeyType(SyntaxKind),
     MemberMissingValue,
+    UnexpectedTrailingComma,
 }
 impl pawarser::parser::SyntaxError for SyntaxError {}
diff --git a/crates/json-pawarser/src/syntax_kind.rs b/crates/json-pawarser/src/syntax_kind.rs
index dfaab13..8713b2d 100644
--- a/crates/json-pawarser/src/syntax_kind.rs
+++ b/crates/json-pawarser/src/syntax_kind.rs
@@ -24,6 +24,9 @@ pub enum SyntaxKind {
     ARRAY,
     ELEMENT,
 
+    // SyntaxKinds for future json5/etc support
+    TRAILING_COMMA,
+
     // Tokens
     // Regexes adapted from [the logos handbook](https://logos.maciej.codes/examples/json_borrowed.html)
     #[token("true")]