From 9e9c7d6b1afef22fbbfcd255f70543291223dea2 Mon Sep 17 00:00:00 2001
From: TEC <git@tecosaur.net>
Date: Mon, 29 Apr 2024 21:44:58 +0800
Subject: [PATCH] Implement eval-able AnnotatedString 2-arg show

The generic/fallback AbstractString 2-arg show omits the annotations,
meaning that eval(Meta.parse(repr(::AnnotatedString))) doesn't
round-trip.

The resolution to this is fairly simple, we just need to implement a
specialised show method. The implementation is fairly obvious, we're
just also able to get away with hiding the vector type annotation since
the constructor is fine without it.
---
 base/strings/annotated.jl | 12 ++++++++++++
 test/strings/annotated.jl |  2 ++
 2 files changed, 14 insertions(+)

diff --git a/base/strings/annotated.jl b/base/strings/annotated.jl
index 2a331c5133f838..5d4c09391a9ef8 100644
--- a/base/strings/annotated.jl
+++ b/base/strings/annotated.jl
@@ -159,6 +159,18 @@ function getindex(s::AnnotatedString, i::Integer)
     end
 end
 
+# To make `AnnotatedString`s repr-evaluable, we need to override
+# the generic `AbstractString` 2-arg show method.
+
+function show(io::IO, s::A) where {A <: AnnotatedString}
+    show(io, A)
+    print(io, '(')
+    show(io, s.string)
+    print(io, ", ")
+    show(IOContext(io, :typeinfo => typeof(annotations(s))), annotations(s))
+    print(io, ')')
+end
+
 ## AbstractChar interface ##
 
 ncodeunits(c::AnnotatedChar) = ncodeunits(c.char)
diff --git a/test/strings/annotated.jl b/test/strings/annotated.jl
index b70a2350757a27..96a494933f648c 100644
--- a/test/strings/annotated.jl
+++ b/test/strings/annotated.jl
@@ -58,6 +58,8 @@
                              (3:3, :val => 2)])),
              Base.AnnotatedString("abc", [(1:2, :val => 1),
                                   (2:3, :val => 2)]))
+    @test chopprefix(sprint(show, str), "Base.") ==
+        "AnnotatedString{String}(\"some string\", , [(1:4, :thing=>0x01), (6:11, :other=>0x02), (1:11, :all=>0x03)])"
 end
 
 @testset "AnnotatedChar" begin