From 6484f4cebfc38cc6dc6934dd6eb4d8b544c27e59 Mon Sep 17 00:00:00 2001
From: Benjamin Deonovic <bdeonovic@gmail.com>
Date: Sat, 31 Dec 2016 15:22:10 -0600
Subject: [PATCH] Add `one` for AbstractString (#19548)

Add `one` for AbstractString
---
 base/strings/basic.jl | 2 ++
 test/strings/basic.jl | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/base/strings/basic.jl b/base/strings/basic.jl
index daa3c8c057a52..876743eead9ec 100644
--- a/base/strings/basic.jl
+++ b/base/strings/basic.jl
@@ -106,6 +106,8 @@ julia> "Hello " * "world"
 """
 (*)(s1::AbstractString, ss::AbstractString...) = string(s1, ss...)
 
+one{T<:AbstractString}(::Union{T,Type{T}}) = convert(T, "")
+
 length(s::DirectIndexString) = endof(s)
 
 """
diff --git a/test/strings/basic.jl b/test/strings/basic.jl
index 60636e1cdd3ff..d7556f339826e 100644
--- a/test/strings/basic.jl
+++ b/test/strings/basic.jl
@@ -416,6 +416,10 @@ foobaz(ch) = reinterpret(Char, typemax(UInt32))
 @test ["b","c"].*"a" == ["ba","ca"]
 @test ["a","b"].*["c" "d"] == ["ac" "ad"; "bc" "bd"]
 
+@test one(String) == ""
+@test prod(["*" for i in 1:3]) == "***"
+@test prod(["*" for i in 1:0]) == ""
+
 # Make sure NULL pointers are handled consistently by String
 @test_throws ArgumentError unsafe_string(Ptr{UInt8}(0))
 @test_throws ArgumentError unsafe_string(Ptr{UInt8}(0), 10)