Setting ans to a expression in REPLBlocks. (#926)

* fix #923: setting ans to a expression in REPLBlocks.

(cherry picked from commit 8d17f68)

src/DocTests.jl

@@ -158,27 +158,19 @@ function eval_repl(block, sandbox, meta::Dict, doc::Documents.Document, page)
             result.hide = REPL.ends_with_semicolon(str)
             (value, success, backtrace, text) = Utilities.withoutput() do
                 disable_color() do
-                    Core.eval(sandbox, ex)
+                    Core.eval(sandbox, Expr(:(=), :ans, ex))
                 end
             end
             result.value = value
             print(result.stdout, text)
-            if success
-                # Redefine the magic `ans` binding available in the REPL.
-                __ans__!(sandbox, result.value)
-            else
+            if !success
                 result.bt = backtrace
             end
         end
         checkresult(sandbox, result, meta, doc)
     end
 end
 
-function __ans__!(m::Module, value)
-    isdefined(m, :__ans__!) || Core.eval(m, :(__ans__!(value) = global ans = value))
-    return Core.eval(m, Expr(:call, () -> m.__ans__!(value)))
-end
-
 function eval_script(block, sandbox, meta::Dict, doc::Documents.Document, page)
     # TODO: decide whether to keep `# output` syntax for this. It's a bit ugly.
     #       Maybe use double blank lines, i.e.

src/Expanders.jl

@@ -548,7 +548,7 @@ function Selectors.runner(::Type{REPLBlocks}, x, page, doc)
         input  = droplines(str)
         (value, success, backtrace, text) = Utilities.withoutput() do
             cd(dirname(page.build)) do
-                Core.eval(mod, :(ans = $(Core.eval(mod, ex))))
+                Core.eval(mod, Expr(:(=), :ans, ex))
             end
         end
         result = value

test/examples/src/index.md

@@ -351,6 +351,11 @@ ex = :(1 + 5)
 eval(ex)
 ```
 
+```@example
+a = 1
+:(a + 1)
+```
+
 # Issue #793
 ```jldoctest
 julia> write("issue793.jl", "\"Hello!\"");