fix deprecations of foldl and mapfoldl (#49)

Author: bicycle1885

src/stream.jl

@@ -135,9 +135,17 @@ end
 # Check that mode is valid.
 macro checkmode(validmodes)
     mode = esc(:mode)
-    quote
-        if !$(foldr((x, y) -> :($(mode) == $(QuoteNode(x)) || $(y)), false, eval(validmodes)))
-            throw(ArgumentError(string("invalid mode :", $(mode))))
+    if VERSION ≥ v"0.7.0-beta.210"
+        quote
+            if !$(foldr((x, y) -> :($(mode) == $(QuoteNode(x)) || $(y)), eval(validmodes), init=false))
+                throw(ArgumentError(string("invalid mode :", $(mode))))
+            end
+        end
+    else
+        quote
+            if !$(foldr((x, y) -> :($(mode) == $(QuoteNode(x)) || $(y)), false, eval(validmodes)))
+                throw(ArgumentError(string("invalid mode :", $(mode))))
+            end
         end
     end
 end

src/testtools.jl

@@ -83,7 +83,11 @@ function test_chunked_read(Encoder, Decoder)
     initialize(encoder)
     for _ in 1:500
         chunks = [rand(alpha, rand(0:100)) for _ in 1:rand(1:100)]
-        data = mapfoldl(x->transcode(encoder, x), vcat, UInt8[], chunks)
+        if VERSION ≥ v"0.7.0-beta.210"
+            data = mapfoldl(x->transcode(encoder, x), vcat, chunks, init=UInt8[])
+        else
+            data = mapfoldl(x->transcode(encoder, x), vcat, UInt8[], chunks)
+        end
         buffer = NoopStream(IOBuffer(data))
         ok = true
         local stream