Merge pull request #204 from JuliaSymbolics/s/par

Par for parallelism

Author: shashi

src/code.jl

@@ -3,7 +3,8 @@ module Code
 using StaticArrays, LabelledArrays, SparseArrays
 
 export toexpr, Assignment, (←), Let, Func, DestructuredArgs, LiteralExpr,
-       SetArray, MakeArray, MakeSparseArray, MakeTuple, AtIndex
+       SetArray, MakeArray, MakeSparseArray, MakeTuple, AtIndex,
+       Par, Multithreaded
 
 import ..SymbolicUtils
 import SymbolicUtils: @matchable, Sym, Term, istree, operation, arguments
@@ -461,6 +462,24 @@ function toexpr(a::MakeTuple, st)
     :(($(toexpr.(a.elems, (st,))...),))
 end
 
+struct Multithreaded end
+"""
+    Par(exprs, reduce)
+
+"""
+struct Par{Typ}
+    exprs::Vector
+    combine
+end
+
+function toexpr(p::Par{Multithreaded}, st)
+    spawns = map(p.exprs) do thunk
+        :(Base.Threads.@spawn $(toexpr(thunk, st)))
+    end
+    quote
+        $(toexpr(p.combine, st))(map(fetch, ($(spawns...),))...)
+    end
+end
 
 """
     LiteralExpr(ex)

test/code.jl

@@ -121,8 +121,10 @@ test_repr(a, b) = @test repr(Base.remove_linenums!(a)) == repr(Base.remove_linen
 
     test_repr(toexpr(MakeSparseArray(spvec)),
               :(SparseVector(10, $(spvec.nzind), [a])))
-
     test_repr(toexpr(MakeTuple((a, b, a+b))),
               :((a,b,$(+)(a,b))))
+
+    @test Par{Multithreaded}([1,2],vcat)|>toexpr|>eval == [1,2]
+    @test @elapsed(Par{Multithreaded}([:(sleep(.3)),:(sleep(.6))],vcat)|>toexpr|>eval) < 0.8
 end