Add do-block support for redirect_std[out,err]

In particular, these simplify testing for warnings

base/stream.jl

@@ -955,6 +955,34 @@ for (x, writable, unix_fd, c_symbol) in
  end
 end
 
+for (F,S) in ((:redirect_stdout, :STDOUT), (:redirect_stderr, :STDERR))
+ @eval function $F(f::Function, stream)
+ STDOLD = $S
+ local ret
+ $F(stream)
+ try
+ ret = f()
+ finally
+ $F(STDOLD)
+ end
+ ret
+ end
+end
+
+"""
+ redirect_stdout(f::Function, stream)
+
+Run the function `f` while redirecting `STDOUT` to `stream`. Upon completion, `STDOUT` is restored to its prior setting.
+"""
+redirect_stdout(f::Function, stream)
+
+"""
+ redirect_stderr(f::Function, stream)
+
+Run the function `f` while redirecting `STDERR` to `stream`. Upon completion, `STDERR` is restored to its prior setting.
+"""
+redirect_stderr(f::Function, stream)
+
 mark(x::LibuvStream) = mark(x.buffer)
 unmark(x::LibuvStream) = unmark(x.buffer)
 reset(x::LibuvStream) = reset(x.buffer)

doc/stdlib/io-network.rst

@@ -350,12 +350,24 @@ General I/O
 
  Replace ``STDOUT`` by stream for all C and Julia level output to ``STDOUT``\ . Note that ``stream`` must be a TTY, a ``Pipe`` or a ``TCPSocket``\ .
 
+.. function:: redirect_stdout(f::Function, stream)
+
+ .. Docstring generated from Julia source
+
+ Run the function ``f`` while redirecting ``STDOUT`` to ``stream``\ . Upon completion, ``STDOUT`` is restored to its prior setting.
+
 .. function:: redirect_stderr([stream])
 
  .. Docstring generated from Julia source
 
  Like ``redirect_stdout``\ , but for ``STDERR``\ .
 
+.. function:: redirect_stderr(f::Function, stream)
+
+ .. Docstring generated from Julia source
+
+ Run the function ``f`` while redirecting ``STDERR`` to ``stream``\ . Upon completion, ``STDERR`` is restored to its prior setting.
+
 .. function:: redirect_stdin([stream])
 
  .. Docstring generated from Julia source

test/show.jl

@@ -318,6 +318,26 @@ let oldout = STDOUT, olderr = STDERR
  end
 end
 
+let filename = tempname()
+ ret = open(filename, "w") do f
+ redirect_stdout(f) do
+ println("hello")
+ [1,3]
+ end
+ end
+ @test ret == [1,3]
+ @test chomp(readstring(filename)) == "hello"
+ ret = open(filename, "w") do f
+ redirect_stderr(f) do
+ warn("hello")
+ [2]
+ end
+ end
+ @test ret == [2]
+ @test contains(readstring(filename), "WARNING: hello")
+ rm(filename)
+end
+
 # issue #12960
 type T12960 end
 let
@@ -576,4 +596,4 @@ end
 # Test compact printing of homogeneous tuples
 @test repr(NTuple{7,Int64}) == "NTuple{7,Int64}"
 @test repr(Tuple{Float64, Float64, Float64, Float64}) == "NTuple{4,Float64}"
-@test repr(Tuple{Float32, Float32, Float32}) == "Tuple{Float32,Float32,Float32}"
+@test repr(Tuple{Float32, Float32, Float32}) == "Tuple{Float32,Float32,Float32}"