From 10331cd262f58f442bef8d3db981cb36b4d98c3c Mon Sep 17 00:00:00 2001
From: Stanislav <vissi@vissi.su>
Date: Fri, 16 Oct 2026 02:33:03 +0400
Subject: [PATCH] Add Release, the obsolete form of Evaluate

Release was superseded by Evaluate and ReleaseHold in Version 2.0, but
WMA still knows it, and old packages use it, for instance to build the
left-hand side of a definition from a variable:
Format[Release[name][k_]] := Subscript[name, k]. Here it simply
evaluates to its argument.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 SYMBOLS_MANIFEST.txt            |  1 +
 mathics/builtin/evaluation.py   | 27 +++++++++++++++++++++++++++
 test/builtin/test_evaluation.py |  9 +++++++++
 3 files changed, 37 insertions(+)

diff --git a/SYMBOLS_MANIFEST.txt b/SYMBOLS_MANIFEST.txt
index 7bab8ea8b6..370cd33b8a 100644
--- a/SYMBOLS_MANIFEST.txt
+++ b/SYMBOLS_MANIFEST.txt
@@ -1023,6 +1023,7 @@ System`Refine
 System`RegularExpression
 System`RegularPolygon
 System`RegularPolygonBox
+System`Release
 System`ReleaseHold
 System`Remove
 System`RemoveDiacritics
diff --git a/mathics/builtin/evaluation.py b/mathics/builtin/evaluation.py
index f4ea135c82..8c469fa93c 100644
--- a/mathics/builtin/evaluation.py
+++ b/mathics/builtin/evaluation.py
@@ -213,6 +213,33 @@ class Evaluate(Builtin):
     summary_text = "evaluate the element, disregarding Hold attributes"
 
 
+class Release(Builtin):
+    """
+    <url>:WMA link:https://reference.wolfram.com/language/ref/Release.html</url>
+
+    <dl>
+      <dt>'Release'[$expr$]
+      <dd>evaluates $expr$. This is an obsolete symbol, superseded by \
+          'Evaluate' and 'ReleaseHold'; it is kept so that old packages \
+          can be read.
+    </dl>
+
+    >> x = 1 + 1; Release[x]
+     = 2
+
+    Old packages use it to build the left-hand side of a definition from \
+    a variable:
+    >> With[{name = h}, Format[Release[name][k_]] := {name, k}]; ToString[h[3]]
+     = {h, 3}
+    #> Clear[x, h]
+    """
+
+    rules = {
+        "Release[x___]": "x",
+    }
+    summary_text = "obsolete form of Evaluate"
+
+
 class Unevaluated(Builtin):
     """
     <url>:WMA link:https://reference.wolfram.com/language/ref/Unevaluated.html</url>
diff --git a/test/builtin/test_evaluation.py b/test/builtin/test_evaluation.py
index 1d635991d8..a73717c5d0 100644
--- a/test/builtin/test_evaluation.py
+++ b/test/builtin/test_evaluation.py
@@ -62,6 +62,15 @@
             None,
         ),
         ("ClearAll[f];", None, None, None),
+        # Release, the obsolete form of Evaluate
+        ("x = 1 + 1; Release[x]", None, "2", None),
+        (
+            "With[{name = h}, f[Release[name][k_]] := {name, k}]; f[h[3]]",
+            None,
+            "{h, 3}",
+            "Release in the left-hand side of a definition",
+        ),
+        ("ClearAll[f, h, x];", None, None, None),
     ],
 )
 def test_evaluation(str_expr, msgs, str_expected, fail_msg):