Add Char * String and Char * Char (JuliaLang#22532)

base/strings/basic.jl

@@ -59,20 +59,21 @@ sizeof(s::AbstractString) = error("type $(typeof(s)) has no canonical binary rep
 eltype(::Type{<:AbstractString}) = Char
 
 """
-```
-*(s::AbstractString, t::AbstractString)
-```
+    *(s::Union{AbstractString, Char}, t::Union{AbstractString, Char}...)
 
-Concatenate strings. The `*` operator is an alias to this function.
-
-# Example
+Concatenate strings and/or characters, producing a [`String`](@ref). This is equivalent
+to calling the [`string`](@ref) function on the arguments.
 
+# Examples
 ```jldoctest
 julia> "Hello " * "world"
 "Hello world"
+
+julia> 'j' * "ulia"
+"julia"
 ```
 """
-(*)(s1::AbstractString, ss::AbstractString...) = string(s1, ss...)
+(*)(s1::Union{Char, AbstractString}, ss::Union{Char, AbstractString}...) = string(s1, ss...)
 
 one(::Union{T,Type{T}}) where {T<:AbstractString} = convert(T, "")
 

test/strings/basic.jl

@@ -484,3 +484,10 @@ Base.endof(x::CharStr) = endof(x.chars)
 # issue #12495: check that logical indexing attempt raises ArgumentError
 @test_throws ArgumentError "abc"[[true, false, true]]
 @test_throws ArgumentError "abc"[BitArray([true, false, true])]
+
+@test "ab" * "cd" == "abcd"
+@test 'a' * "bc" == "abc"
+@test "ab" * 'c' == "abc"
+@test 'a' * 'b' == "ab"
+@test 'a' * "b" * 'c' == "abc"
+@test "a" * 'b' * 'c' == "abc"