From 4cc20ad21179dbf61b078741cacf2d30de8d5d4c Mon Sep 17 00:00:00 2001
From: Neven Sajko <s@purelymail.com>
Date: Mon, 27 Nov 2023 22:46:39 +0100
Subject: [PATCH] Add an `operate` method for `abs` (#243)

---
 src/interface.jl  | 4 ++++
 test/interface.jl | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/interface.jl b/src/interface.jl
index 5b3452e..c825ddb 100644
--- a/src/interface.jl
+++ b/src/interface.jl
@@ -190,6 +190,10 @@ function operate end
 #     custom `operate` method.
 operate(::typeof(-), x) = -x
 
+# This is not efficient, as it may make unnecessary intermediate copies,
+# but seems like the best way to write a generic implementation.
+operate(::typeof(abs), x) = abs(copy_if_mutable(x))
+
 function operate(
     op::Union{
         typeof(+),
diff --git a/test/interface.jl b/test/interface.jl
index 0f3c4e3..9e3e654 100644
--- a/test/interface.jl
+++ b/test/interface.jl
@@ -97,7 +97,7 @@ end
 @testset "operate" begin
     @testset "$T" for T in (Int, BigInt, Rational{Int})
         x = T(7)
-        @testset "1-ary $op" for op in [+, *, gcd, lcm]
+        @testset "1-ary $op" for op in [+, *, gcd, lcm, abs]
             a = op(x)
             b = MA.operate(op, x)
             @test a == b