From 665279aedb18501938c934d46aa593a26a506b3e Mon Sep 17 00:00:00 2001
From: Simeon Schaub <simeondavidschaub99@gmail.com>
Date: Fri, 23 Oct 2020 23:08:28 +0200
Subject: [PATCH] =?UTF-8?q?add=20'=E1=B5=80=20postfix=20operator=20for=20t?=
 =?UTF-8?q?ranspose=20(#38062)?=
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---
 NEWS.md                              |  1 +
 base/exports.jl                      |  1 +
 base/operators.jl                    |  1 +
 stdlib/LinearAlgebra/src/adjtrans.jl | 12 ++++++++++++
 test/operators.jl                    |  3 +++
 5 files changed, 18 insertions(+)

diff --git a/NEWS.md b/NEWS.md
index a8401633fe11a..0b7cbb37205ba 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -106,6 +106,7 @@ New library features
   inserting or consuming the first dimension depending on the ratio of `sizeof(T)` and `sizeof(S)`.
 * New `append!(vector, collections...)` and `prepend!(vector, collections...)` methods accept multiple
   collections to be appended or prepended ([#36227]).
+* The postfix operator `'ᵀ` can now be used as an alias for `transpose` ([#38043]).
 
 Standard library changes
 ------------------------
diff --git a/base/exports.jl b/base/exports.jl
index 287866ca59503..3e7e6ce7647e4 100644
--- a/base/exports.jl
+++ b/base/exports.jl
@@ -466,6 +466,7 @@ export
 # linear algebra
     var"'", # to enable syntax a' for adjoint
     adjoint,
+    var"'ᵀ",
     transpose,
     kron,
     kron!,
diff --git a/base/operators.jl b/base/operators.jl
index bdf1735bad884..55de805671a5f 100644
--- a/base/operators.jl
+++ b/base/operators.jl
@@ -547,6 +547,7 @@ end
 function kron! end
 
 const var"'" = adjoint
+const var"'ᵀ" = transpose
 
 """
     \\(x, y)
diff --git a/stdlib/LinearAlgebra/src/adjtrans.jl b/stdlib/LinearAlgebra/src/adjtrans.jl
index c9f7326116bff..456441163f9de 100644
--- a/stdlib/LinearAlgebra/src/adjtrans.jl
+++ b/stdlib/LinearAlgebra/src/adjtrans.jl
@@ -136,6 +136,7 @@ julia> x'x
 adjoint(A::AbstractVecOrMat) = Adjoint(A)
 
 """
+    A'ᵀ
     transpose(A)
 
 Lazy transpose. Mutating the returned object should appropriately mutate `A`. Often,
@@ -145,6 +146,9 @@ that this operation is recursive.
 This operation is intended for linear algebra usage - for general data manipulation see
 [`permutedims`](@ref Base.permutedims), which is non-recursive.
 
+!!! compat "Julia 1.6"
+    The postfix operator `'ᵀ` requires Julia 1.6.
+
 # Examples
 ```jldoctest
 julia> A = [3+2im 9+2im; 8+7im  4+6im]
@@ -156,6 +160,14 @@ julia> transpose(A)
 2×2 Transpose{Complex{Int64}, Matrix{Complex{Int64}}}:
  3+2im  8+7im
  9+2im  4+6im
+
+julia> x = [3, 4im]
+2-element Vector{Complex{Int64}}:
+ 3 + 0im
+ 0 + 4im
+
+julia> x'ᵀx
+-7 + 0im
 ```
 """
 transpose(A::AbstractVecOrMat) = Transpose(A)
diff --git a/test/operators.jl b/test/operators.jl
index fb0af5b552047..a806c5cead5df 100644
--- a/test/operators.jl
+++ b/test/operators.jl
@@ -243,3 +243,6 @@ end
     @test gt5(6) && !gt5(5)
     @test lt5(4) && !lt5(5)
 end
+
+a = rand(3, 3)
+@test transpose(a) === a'ᵀ