Add one for AbstractString (#19548)

Add `one` for AbstractString
JuliaLang · Dec 31, 2016 · 6484f4c · 6484f4c
1 parent de957a5
commit 6484f4c
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diff --git 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
@@ -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)
-Original file line number
+Diff line change
@@ Expand Up / @@ -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)
     """
@@ Expand Down @@