add pipe (fix #47)

README.md

@@ -60,6 +60,8 @@ Currently, the `@compat` macro supports the following syntaxes:
 
 * `beginswith` is now `startswith` [#9583](https://github.com/JuliaLang/julia/pull/9583)
 
+* `|>`, `>>`, `.>`, and `.>>` are now `pipe` [#10211](https://github.com/JuliaLang/julia/pull/10211)
+
 ## New macros
 
 * `@inline` and `@noinline` have been added. On 0.3, these are "no-ops," meaning they don't actually do anything.

src/Compat.jl

@@ -80,6 +80,29 @@ if VERSION < v"0.4.0-dev+2014"
     export sizehint!
 end
 
+if VERSION < v"0.4.0-dev+3413"
+    # based on pipe in base/process.jl:
+    function pipe(src::AbstractCmd; stdin=nothing, stdout=nothing, stderr=nothing, append::Bool=false)
+        if append && stdout === nothing && stderr === nothing
+            error("append set to true, but no output redirections specified")
+        end
+        if stdin !== nothing
+            cmd = stdin |> cmd
+        end
+        if stdout !== nothing
+            cmd = append ? cmd >> stdout : cmd |> stdout
+        end
+        if stderr !== nothing
+            cmd = append ? cmd .>> stderr : cmd .> stderr
+        end
+        return cmd
+    end
+    pipe(cmd::AbstractCmd, dest) = pipe(cmd, stdout=dest)
+    pipe(src::Union(Redirectable,AbstractString), cmd::AbstractCmd) = pipe(cmd, stdin=src)
+    pipe(a, b, c, d...) = pipe(pipe(a,b), c, d...)
+    export pipe
+end
+
 function rewrite_dict(ex)
     length(ex.args) == 1 && return ex
 

test/runtests.jl

@@ -93,3 +93,6 @@ end
 @test CartesianTest.f(1,2,3) == (1,2,3)
 @test CartesianTest.f(1,2,3,4) == (1,2,3,4)
 @test CartesianTest.f(1,2,3,4,5) == (1,2,3,4,5)
+
+@test readall(pipe(`echo hello`, `sort`)) == "hello\n"
+@test success(pipe(`true`, `true`))