From c2bfc9ec52c5cdcfa37dd6e39e4fd5c032568a62 Mon Sep 17 00:00:00 2001
From: Alex Orlenko <zxteam@protonmail.com>
Date: Mon, 19 Jun 2023 23:28:08 +0100
Subject: [PATCH] Implement `PartialEq<[T]>` for tables

---
 src/table.rs   | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/table.rs | 49 +++++++++++++++----------------------------------
 2 files changed, 65 insertions(+), 34 deletions(-)

diff --git a/src/table.rs b/src/table.rs
index fdcbfe7..e87ecc9 100644
--- a/src/table.rs
+++ b/src/table.rs
@@ -797,6 +797,56 @@ impl<'lua> AsRef<Table<'lua>> for Table<'lua> {
     }
 }
 
+impl<'lua, T> PartialEq<[T]> for Table<'lua>
+where
+    T: IntoLua<'lua> + Clone,
+{
+    fn eq(&self, other: &[T]) -> bool {
+        let lua = self.0.lua;
+        let state = lua.state();
+        unsafe {
+            let _sg = StackGuard::new(state);
+            assert_stack(state, 4);
+
+            lua.push_ref(&self.0);
+
+            let len = ffi::lua_rawlen(state, -1) as usize;
+            for i in 0..len {
+                ffi::lua_rawgeti(state, -1, (i + 1) as _);
+                let val = lua.pop_value();
+                if val == Nil {
+                    return i == other.len();
+                }
+                match other.get(i).map(|v| v.clone().into_lua(lua)) {
+                    Some(Ok(other_val)) if val == other_val => continue,
+                    _ => return false,
+                }
+            }
+        }
+        true
+    }
+}
+
+impl<'lua, T> PartialEq<&[T]> for Table<'lua>
+where
+    T: IntoLua<'lua> + Clone,
+{
+    #[inline]
+    fn eq(&self, other: &&[T]) -> bool {
+        self == *other
+    }
+}
+
+impl<'lua, T, const N: usize> PartialEq<[T; N]> for Table<'lua>
+where
+    T: IntoLua<'lua> + Clone,
+{
+    #[inline]
+    fn eq(&self, other: &[T; N]) -> bool {
+        self == &other[..]
+    }
+}
+
 /// An extension trait for `Table`s that provides a variety of convenient functionality.
 pub trait TableExt<'lua>: Sealed {
     /// Calls the table as function assuming it has `__call` metamethod.
diff --git a/tests/table.rs b/tests/table.rs
index c71b5a3..69c7ede 100644
--- a/tests/table.rs
+++ b/tests/table.rs
@@ -57,6 +57,7 @@ fn test_table() -> Result<()> {
             .collect::<Result<Vec<i64>>>()?,
         vec![1, 2, 3, 4, 5]
     );
+    assert_eq!(table1, [1, 2, 3, 4, 5]);
 
     assert_eq!(table2.len()?, 0);
     assert_eq!(
@@ -66,12 +67,10 @@ fn test_table() -> Result<()> {
             .collect::<Result<Vec<(i64, i64)>>>()?,
         vec![]
     );
-    assert_eq!(
-        table2.sequence_values().collect::<Result<Vec<i64>>>()?,
-        vec![]
-    );
+    assert_eq!(table2, [0; 0]);
 
     // sequence_values should only iterate until the first border
+    assert_eq!(table3, [1, 2]);
     assert_eq!(
         table3.sequence_values().collect::<Result<Vec<i64>>>()?,
         vec![1, 2]
@@ -116,17 +115,12 @@ fn test_table_push_pop() -> Result<()> {
     // Test raw access
     let table1 = lua.create_sequence_from(vec![123])?;
     table1.raw_push(321)?;
-    assert_eq!(
-        table1
-            .clone()
-            .raw_sequence_values::<i64>()
-            .collect::<Result<Vec<_>>>()?,
-        vec![123, 321]
-    );
+    assert_eq!(table1, [123, 321]);
     assert_eq!(table1.raw_pop::<i64>()?, 321);
     assert_eq!(table1.raw_pop::<i64>()?, 123);
     assert_eq!(table1.raw_pop::<Value>()?, Value::Nil); // An extra pop should do nothing
     assert_eq!(table1.raw_len(), 0);
+    assert_eq!(table1, [0; 0]);
 
     // Test access through metamethods
     let table2 = lua
@@ -144,6 +138,13 @@ fn test_table_push_pop() -> Result<()> {
         .eval::<Table>()?;
     table2.push(345)?;
     assert_eq!(table2.len()?, 2);
+    assert_eq!(
+        table2
+            .clone()
+            .raw_sequence_values::<i64>()
+            .collect::<Result<Vec<_>>>()?,
+        vec![]
+    );
     assert_eq!(table2.pop::<i64>()?, 345);
     assert_eq!(table2.pop::<i64>()?, 234);
     assert_eq!(table2.pop::<Value>()?, Value::Nil);
@@ -205,29 +206,9 @@ fn test_table_sequence_from() -> Result<()> {
 
     let get_table = lua.create_function(|_, t: Table| Ok(t))?;
 
-    assert_eq!(
-        get_table
-            .call::<_, Table>(vec![1, 2, 3])?
-            .sequence_values()
-            .collect::<Result<Vec<i64>>>()?,
-        vec![1, 2, 3]
-    );
-
-    assert_eq!(
-        get_table
-            .call::<_, Table>([1, 2, 3].as_ref())?
-            .sequence_values()
-            .collect::<Result<Vec<i64>>>()?,
-        vec![1, 2, 3]
-    );
-
-    assert_eq!(
-        get_table
-            .call::<_, Table>([1, 2, 3])?
-            .sequence_values()
-            .collect::<Result<Vec<i64>>>()?,
-        vec![1, 2, 3]
-    );
+    assert_eq!(get_table.call::<_, Table>(vec![1, 2, 3])?, [1, 2, 3]);
+    assert_eq!(get_table.call::<_, Table>([4, 5, 6])?, [4, 5, 6]);
+    assert_eq!(get_table.call::<_, Table>([7, 8, 9].as_slice())?, [7, 8, 9]);
 
     Ok(())
 }