diff --git a/porcupine-core.cabal b/porcupine-core.cabal
--- a/porcupine-core.cabal
+++ b/porcupine-core.cabal
@@ -4,10 +4,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: f4672c1d7de06695f07c27b5c5621ceffb7e30abb9469d2c87f60c0dbf8a6fff
+-- hash: ec1ad6361b97225f0238ae406131c6d302b0bc6f952f27d26b360d357669d832
 
 name:           porcupine-core
-version:        0.1.0.0
+version:        0.1.0.1
 synopsis:       Express portable, composable and reusable data tasks and pipelines
 description:    porcupine is centered around the PTask datatype, which represents a
                 computation that will request access to some resources (both in read and write
@@ -16,18 +16,17 @@
                 pipeline of tasks. The resources and parameters are organized in a tree which
                 will be automatically exposed to the outside world. This makes the pipeline
                 self-documented, and makes it so any option or file required at some point by
-                any task can be visualized and set/remapped (via a combination of a YAML/JSON
-                config file and command-line arguments) before the pipeline will run. That
-                means that the PTasks are completely agnostic of their data inputs, and that
-                new data sources can be added without having to change any of the tasks' logic
-                or even their types. This is done via the LocationAccessor
+                any task can be visualized and set or remapped (via a combination of a YAML or
+                JSON config file and command-line arguments) before the pipeline will
+                run. That means that the PTasks are completely agnostic of their data inputs,
+                and that new data sources can be added without having to change any of the
+                tasks' logic or even their types. This is done via the LocationAccessor
                 typeclass. `porcupine-core` provides only access to local files (via
                 resourcet), other location accessors will be in separate packages. See for
-                instance the <https://hackage.haskell.org/package/porcupine-http
-                `porcupine-http`> package to access HTTP urls. PTasks also provide caching
-                thanks to the funflow package. See the README at
-                <https://github.com/tweag/porcupine#README.md> and the examples in
-                `porcupine-core` package.
+                instance the <https://hackage.haskell.org/package/porcupine-http> package to
+                access HTTP urls. PTasks also provide caching thanks to the funflow
+                package. See the README at <https://github.com/tweag/porcupine#README.md> and
+                the examples in `porcupine-core` package.
 category:       Data, Arrows, Combinators, Control, Pipes, Streaming, Numerical, JSON
 homepage:       https://github.com/tweag/porcupine#readme
 bug-reports:    https://github.com/tweag/porcupine/issues
@@ -41,6 +40,10 @@
   type: git
   location: https://github.com/tweag/porcupine
 
+flag useMonadBayes
+  manual: True
+  default: False
+
 library
   exposed-modules:
       Control.Arrow.FoldA
@@ -197,6 +200,10 @@
     , vinyl
     , yaml
     , zlib
+  if flag(useMonadBayes)
+    buildable: True
+  else
+    buildable: False
   default-language: Haskell2010
 
 executable example0