diff --git a/src/Compat.jl b/src/Compat.jl
index 1a40bc175066b..928e2aec3be0d 100644
--- a/src/Compat.jl
+++ b/src/Compat.jl
@@ -400,4 +400,30 @@ if VERSION < v"0.4.0-dev+2861"
     export muladd
 end
 
+if VERSION < v"0.4.0-dev+4734"
+    function is_valid_utf32(str::Union(Vector{Char}, Vector{UInt32}))
+        for i=1:length(str)
+            @inbounds if !is_valid_char(reinterpret(UInt32, str[i])) ; return false ; end
+        end
+        return true
+    end
+    is_valid_utf32(str::UTF32String) = is_valid_utf32(str.data)
+    export is_valid_utf32
+end
+
+if VERSION < v"0.4.0-dev+4939"
+    import Base.isvalid
+    isvalid(ch::Char)         = is_valid_char(ch)
+    isvalid(str::ASCIIString) = is_valid_ascii(str)
+    isvalid(str::UTF8String)  = is_valid_utf8(str)
+    isvalid(str::UTF16String) = is_valid_utf16(str)
+    isvalid(str::UTF32String) = is_valid_utf32(str)
+    isvalid(::Type{Char}, ch)         = is_valid_char(ch)
+    isvalid(::Type{ASCIIString}, str) = is_valid_ascii(str)
+    isvalid(::Type{UTF8String},  str) = is_valid_utf8(str)
+    isvalid(::Type{UTF16String}, str) = is_valid_utf16(str)
+    isvalid(::Type{UTF32String}, str) = is_valid_utf32(str)
+    export isvalid
+end
+
 end # module
diff --git a/test/runtests.jl b/test/runtests.jl
index 203b7ef2a4104..ec9f1d01c87f0 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -298,3 +298,25 @@ end
 
 # fma and muladd
 @test fma(3,4,5) == 3*4+5 == muladd(3,4,5)
+
+# is_valid_utf32
+s = utf32("abc")
+@test is_valid_utf32(s)
+s = utf32(UInt32[65,0x110000])
+@test !is_valid_utf32(s)
+
+# isvalid
+let s = "abcdef", u8 = "abcdef\uff", u16 = utf16(u8), u32 = utf32(u8),
+    bad32 = utf32(UInt32[65,0x110000]), badch = Char[0x110000][1]
+
+    @test !isvalid(bad32)
+    @test !isvalid(badch)
+    @test isvalid(s)
+    @test isvalid(u8)
+    @test isvalid(u16)
+    @test isvalid(u32)
+    @test isvalid(ASCIIString, s)
+    @test isvalid(UTF8String,  u8)
+    @test isvalid(UTF16String, u16)
+    @test isvalid(UTF32String, u32)
+end