Support do-block syntax for redirect_std*

README.md

@@ -144,6 +144,8 @@ Currently, the `@compat` macro supports the following syntaxes:
 
 * [`normalize`](http://docs.julialang.org/en/latest/stdlib/linalg/?highlight=normalize#Base.normalize) and [`normalize!`](http://docs.julialang.org/en/latest/stdlib/linalg/?highlight=normalize#Base.normalize!), normalizes a vector with respect to the p-norm ([#13681](https://github.com/JuliaLang/julia/pull/13681))
 
+* `redirect_stdout`, `redirect_stderr`, and `redirect_stdin` take an optional function as a first argument, `redirect_std*(f, stream)`, so that one may use `do` block syntax (as first available for Julia 0.6).
+
 ## Renamed functions
 
 * `pointer_to_array` and `pointer_to_string` have been replaced with `unsafe_wrap(Array, ...)` and `unsafe_wrap(String, ...)` respectively.

src/Compat.jl

@@ -1452,4 +1452,15 @@ else
     end
 end
 
+import Base: redirect_stdin, redirect_stdout, redirect_stderr
+if VERSION < v"0.6.0-dev.374"
+    for (F,S) in ((:redirect_stdin, :STDIN), (:redirect_stdout, :STDOUT), (:redirect_stderr, :STDERR))
+        @eval function $F(f::Function, stream)
+            STDOLD = $S
+            $F(stream)
+            try f() finally $F(STDOLD) end
+        end
+    end
+end
+
 end # module

test/runtests.jl

@@ -1354,3 +1354,30 @@ let n=5, a=rand(n), incx=1, b=rand(n), incy=1
           &n, a, &incx, b, &incy)
     @test a == b
 end
+
+# do-block redirect_std*
+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")
+    ret = open(filename) do f
+        redirect_stdin(f) do
+            readline()
+        end
+    end
+    @test contains(ret, "WARNING: hello")
+    rm(filename)
+end