Don't use MacroTools for macro mt_out_of_order

MacroTools turns `(a[i] = b;)` into `a[i] = b`.
We don't want that in @mt_out_of_order, since the user's intent would be
to run `(a[i] = b;)` in parallel, not just `b`.

Author: oschulz

Project.toml

@@ -4,7 +4,6 @@ version = "0.4.1"
 
 [deps]
 Distributed = "8ba89e20-285c-5b6f-9357-94700520ee1b"
-MacroTools = "1914dd2f-81c6-5fcd-8719-6d5c9610ff09"
 
 [compat]
 MacroTools = "0.5"

src/ParallelProcessingTools.jl

@@ -7,8 +7,6 @@ module ParallelProcessingTools
 using Base.Threads
 using Distributed
 
-using MacroTools
-
 include("threadsafe.jl")
 include("threadlocal.jl")
 include("onthreads.jl")

src/onthreads.jl

@@ -225,7 +225,6 @@ end
 export @mt_async
 
 
-using MacroTools
 """
     @mt_out_of_order begin expr... end
 
@@ -254,8 +253,9 @@ macro mt_out_of_order(ex)
     tasks = gensym(:tasks)
     handle_results = Vector{Expr}()
     for i in idxs
-        trg = nothing; val = nothing;
-        if @capture(exprs[i], trg_ = val_)
+        if exprs[i] isa Expr && exprs[i].head == :(=)
+            trg = exprs[i].args[1]
+            val = exprs[i].args[2]
             if val isa Expr
                 exprs[i] = :(push!($tasks, @mt_async($(esc(val)))))
                 push!(handle_results, :($(esc(trg)) = fetch(popfirst!($tasks))))