From 007bd83a2ab18efcf1aeace499674b4127ebeb7c Mon Sep 17 00:00:00 2001
From: rocky <rb@dustyfeet.com>
Date: Mon, 30 Sep 2024 22:14:06 -0400
Subject: [PATCH] Start CheckAbort[] builtin function

Just basic implementation. Right now, we don't handle options.
---
 CHANGES.rst                   |  5 +++--
 mathics/builtin/procedural.py | 30 ++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/CHANGES.rst b/CHANGES.rst
index e8a99c4bc..e7b23fa00 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -6,6 +6,7 @@ CHANGES
 New Builtins
 ++++++++++++
 
+* ``CheckAbort``
 * ``SetEnvironment``
 
 Compatibility
@@ -22,9 +23,9 @@ Operator precedence has been gone over and is picked up in tables from the Mathi
 Performance
 -----------
 
-* `Blank*` patterns without arguments are now singletons.
+* ``Blank*`` patterns without arguments are now singletons.
+
 
-  
 7.0.0
 -----
 
diff --git a/mathics/builtin/procedural.py b/mathics/builtin/procedural.py
index 9d1eef551..daff081d8 100644
--- a/mathics/builtin/procedural.py
+++ b/mathics/builtin/procedural.py
@@ -152,6 +152,36 @@ def eval_with_form_and_fn(self, expr, form, f, evaluation):
         return ret
 
 
+class CheckAbort(Builtin):
+    """
+    <url>:WMA link:
+    https://reference.wolfram.com/language/ref/CheckAbort.html</url>
+
+    <dl>
+      <dt>'CheckAbort[$expr$, $failexpr$]'
+        <dd>evaluates $expr, returning $failexpr$ if an abort occurs.
+    </dl>
+
+    >> CheckAbort[Abort[]; 1, 2] + x
+     = 2 + x
+
+    >> CheckAbort[1, 2] + x
+     = 1 + x
+    """
+
+    attributes = A_HOLD_ALL | A_PROTECTED
+
+    summary_text = "catch an Abort[] exception"
+
+    def eval(self, expr, failexpr, evaluation):
+        "CheckAbort[expr_, failexpr_]"
+
+        try:
+            return expr.evaluate(evaluation)
+        except AbortInterrupt:
+            return failexpr
+
+
 class CompoundExpression(BinaryOperator):
     """
     <url>:WMA link: